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720 Hardware User Guide

N720 Hardware User

Guide

Version 1.3

720 Hardware User Guide

is the trademark of Neoway Technology Co., Ltd.

All other trademarks and trade names mentioned in this document are the property of their

respective holders.

Remarks

This document is intended for system engineers (SEs), development engineers, and test

engineers.

The information in this document is subject to change without notice due to product version

update or other reasons.

Every effort has been made in preparation of this document to ensure accuracy of the

contents, but all statements, information, and recommendations in this document do not

constitute a warranty of any kind, express or implied.

Neoway provides customers complete technical support. If you have any question, please

contact your account manager or email to

Sales@neoway.com

Support@neoway.com

Website: http://www.neoway.com

720 Hardware User Guide

Revision Record

Version Changes Date

V1.0  Initial draft 2016-08

V1.1  Added bands information of different areas 2016-09

V1.2  Modified pin the description 2016-10

V1.3  Modify the UIM card part and delete the UIM2 part

 Improve band information

 Modify part of the pin definition (the original pin78 RING,

pin80 LIGHT are modified to pin13 RING, pin83 LIGHT.

Pin13 and pin83 are NC)

 Modify part of description

2016-12

720 Hardware User Guide

Contents

1 Introduction to N720 ........................................................................................................ 1

1.1 Overview ........................................................................................................................................... 1

1.2 Block Diagram .................................................................................................................................. 2

1.3 Features ............................................................................................................................................ 2

2 Application Interfaces ..................................................................................................... 5

2.1 Specifications and Pin Definition ................................................................................................... 5

2.2 Pin Description ................................................................................................................................. 6

2.3 Power Control Interfaces .............................................................................................................. 13

2.3.1 VBAT ...................................................................................................................................... 13

2.3.2 VDDIO_1P8 ........................................................................................................................... 17

2.3.3 ON/OFF ................................................................................................................................. 17

2.3.4 RESET ................................................................................................................................... 19

2.4 USB Interface ................................................................................................................................. 21

2.5 UIM Card Interface ........................................................................................................................ 22

2.6 GPIO ................................................................................................................................................ 24

1.1.1 UART ...................................................................................................................................... 24

2.6.2 ADC ........................................................................................................................................ 26

2.6.3 NET_LIGHT ........................................................................................................................... 26

2.6.4 DTR ........................................................................................................................................ 27

2.6.5 RING Signal Indicator .......................................................................................................... 27

2.7 Commissioning Interfaces ............................................................................................................ 28

2.7.1 FORCE_USB_BOOT ........................................................................................................... 28

3 RF Interface ...................................................................................................................... 29

3.1 2G/3G/4G RF Design and PCB Layout ...................................................................................... 29

3.2 GPS RF Design and PCB Layout ............................................................................................... 31

3.2.1 GPS Impedance ................................................................................................................... 31

3.2.2 Active GPS Antenna Design ............................................................................................... 31

4 Electric Feature and Reliability ................................................................................... 33

4.1 Electric Feature .............................................................................................................................. 33

4.2 Temperature.................................................................................................................................... 33

4.3 ESD Protection ............................................................................................................................... 34

5 RF Feature ........................................................................................................................ 35

5.1 Work Band ...................................................................................................................................... 35

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5.2 TX Power and RX Sensitivity ....................................................................................................... 36

6 Mechanical Feature ........................................................................................................ 37

6.1 Dimensions ..................................................................................................................................... 37

6.2 PCB Foot Print ............................................................................................................................... 38

7 Mounting and Packaging ............................................................................................. 39

7.1 Mounting the Module onto the Application Board ..................................................................... 39

7.2 Package .......................................................................................................................................... 39

8 SMT TemperatureCurve ................................................................................................ 40

9 Abbreviations .................................................................................................................. 41

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Table of Figures

Figure 1-1 N720 block diagram ........................................................................................................... 2

Figure 2-1 Top view of N720 ................................................................................................................ 5

Figure 2-2 Current peaks and voltage drops ................................................................................... 14

Figure 2-3 Capacitors used for the power supply ........................................................................... 14

Figure 2-4 Reference design of power supply control .................................................................... 15

Figure 2-5 Reference design of power supply controlled by p-MOSFET .................................... 15

Figure 2-6 Reference designs of separated power supply ............................................................ 17

Figure 2-7 Push switch controlling .................................................................................................... 18

Figure 2-8 MCU controlling ................................................................................................................ 18

Figure 2-9 N720 power-on/off sequence .......................................................................................... 18

Figure 2-10 N720 power-off sequence ............................................................................................. 19

Figure 2-11 Reset controlled by button ............................................................................................. 20

Figure 2-12 Reset circuit with triode separating .............................................................................. 20

Figure 2-13 N720 reset sequence ..................................................................................................... 20

Figure 2-14 USB circuit ....................................................................................................................... 21

Figure 2-15 Reference design of SIM card interface ...................................................................... 22

Figure 2-16 Encapsulation .................................................................................................................. 23

Figure 2-17 Reference design of the UART interface .................................................................... 25

Figure 2-18 Recommended level shifting circuit ............................................................................. 25

Figure 2-19 LED indicator driven by transistor ................................................................................ 26

Figure 2-20 RING indicator for incoming call ................................................................................... 28

Figure 2-21 RING indicator for SMS ................................................................................................. 28

Figure 2-22 Reference design of the fast boot interface ................................................................ 28

Figure 3-1 Reference of antenna matching design ......................................................................... 29

Figure 3-2 Recommended RF PCB design ..................................................................................... 30

Figure 3-3 Encapsulation specifications of Murata RF connector ................................................ 30

Figure 3-4 RF connections ................................................................................................................. 30

Figure 3-5 GPS RF structure ............................................................................................................. 31

Figure 3-6 Power supply reference for active antenna .................................................................. 32

Figure 6-1 Dimensions of N720 ......................................................................................................... 37

Figure 6-2 N720PCBFoot Print(Top View) ....................................................................................... 38

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Figure 8-1 Temperature curve ............................................................................................................ 40

720 Hardware User Guide

Table of Tables

Table 1-1 N720 baseband and wireless features ............................................................................. 2

Table 2-1 N720 dimensions ................................................................................................................. 5

Table 2-2 N720 pin description ............................................................................................................ 6

Table 2-3 GPIO .................................................................................................................................... 24

Table 4-1 N720 Electric Feature ........................................................................................................ 33

Table 4-2 Temperature Feature ......................................................................................................... 33

Table 4-3 N720 ESD feature .............................................................................................................. 34

Table 5-1 N720 work band ................................................................................................................. 35

Table 5-2 N720 RF power and RX sensitivity .................................................................................. 36

720 Hardware User Guide

1 Introduction to N720

1.1 Overview

N720 is an industrial 4G module that is developed on Qualcomm platform. Its dimensions are

30mm x 28 mm x 2.8mm and it is with industrial-grade high-performance: ultra-wide operating

temperature of -40 ℃ to +85 ℃, electrostatic capacity of 8KV. It is well applicable to electric

terminals, in-vehicle computers, POS, industrial routers, and other IoT terminals with the

following features:

 ARM Cortex-A7 processors, 1.2 GHz main frequency, 256 kB L2 cache, 28 nm

 GSM/GPRS/EDGE &WCDMA R99

 SIM/ADC/UART

N720 series include the following versions:

Band

Version

LTE

1 B2 B3 B4 B5 B

8B9 B1

CN ● ● ● ● ● ● ● ●

JP ● ● ● ● ●

EU ● ● ● ● ● ●

US ● ● ● ● ● ●

Band

Version

UMTS GSM

B1 B2 B4 B5 B8 B9 B19 850 900 1800 1900

CN ● ● ● ●

JP ● ● ● ●

EU ● ● ● ● ● ●

US ● ● ● ● ● ● ●

CN: China JP: Japan EU: Europe US：The United States

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1.2 Block Diagram

Figure 1-1 shows the block diagram of N720 Modular only,

Figure 1-1 N720 block diagram

1.3 Features

Table 1-1 N720 baseband and wireless features

Specifications Description

Power supply VBAT: 3.3V to 4.3V, TYP: 3.8 V

Current in sleep

mode 4mA

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Temperature

Operating temperature: -40°C to +85°C

Limited: -40°C to +85°C

Storage temperature: -40°Cto +85°C

Processor

ARM Cortex-A7 processor

Main frequency: 1.2 GHz

256kB L2 cache

Band

CN:

 GSM/GPRS/EDGE:900M/1800M

 TD_SCDMA:B34/B39

 UMTS:B1/B8

 LTE-FDD B1/B3/B5

 LTE-TDD B38/B39/B40/B41

JP:

 UMTS: B1/B8/B9/B19

 FDD-LTE: B1/B3/B8/B9/B19

EU:

 GSM/GPRS/EDGE:850M/ 900M/1800M/1900M

 UMTS: B1/B8

 FDD-LTE: B1/B3/B5/B7/B8/B20

 TDD-LTE: B40；

US:

 GSM/GPRS/EDGE: 850M/1900M

 UMTS: B2/B4/B5

 FDD-LTE: B2/B4/B5/B7/B12/B17

Rate

GSM:GPRS,EDGE

WCDMA:

LTE FDD: non-CA cat4, Max 150Mbps(DL)/Max 50Mbps(UL)

LTE TDD: non-CA cat4,Max 130Mbps(DL)/Max 35Mbps(UL)

Transmit power

GSM850: +34dBm (Power Class 4)

EGSM900: +34dBm (Power Class 4)

DCS1800: +31.5dBm (Power Class 1)

PCS1900: +31.5dBm (Power Class 1)

EDGE 850MHz: +28.5dBm (Power Class E2)

EDGE 900MHz: +28.5dBm (Power Class E2)

720 Hardware User Guide

EDGE1800MHz: +27.5dBm (Power Class E2)

EDGE1900MHz: +27.5dBm (Power Class E2)

UMTS: 24dBm (Power Class 3)

LTE: +23dBm (Power Class 3)

Antenna feature 50 impedance

UART At most 4 Mbps, 1 group

UIM 1 groups, 1.8V/3V dual-voltage adaptive

USB 1 group of USB2.0 high-speed interface

ADC 2 groups of 16-bit ADC, input voltage ranging from 0.1 to 1.7V

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2 Application Interfaces

N720 adopts 100-pins LGA encapsulation.

2.1 Specifications and Pin Definition

Table 2-1 N720 dimensions

Specifications N720

Dimensions 30mm*28 mm*2.8mm(H*W*D)

Weight 5.1g

Package 100-Pin LGA

Figure 2-1 Top view of N720

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2.2 Pin Description

IO: input/output

DI: Digital input

DO: Digital output

PI: Power input

PO: Power output

AI: Analog input

AO: Analog output

Table 2-2 N720 pin description

Name Pin I/O Function Level Feature (V) Power

Domain Remarks

Power Supply

VABT 27, 28, 29 PI Main power supply input Vmax=4.3V The power supply can

provide up to 3A current

VDDIO _1P8

45 PO 1.8 V power supply output Vnorm=1.8V;

Imax=100mA 1.8V

Supply power for IO level

shifting circuit. Leave it

disconnected if you do not

use it.

GND 1, 14, 17, 20, GND

720 Hardware User Guide

26, 30, 31,

44, 49, 74,

75, 77, 91,

93, 95, 97,

98, 99, 100

Power on/off and reset

RESET

32 DI Reset input

VIL min=-0V;

VIL max=0.5V;

VIH min=1.2V;

VIH max=2.1V;

1.8V

Low level triggers the ON

status and can control the

power off and reset.

PWRKEY 33 DI Power ON/OFF 1.8V

Low level triggers the ON

status.

It is pulled up by an internal

200 Kresistor.

PON_TRIG 34 DI PON_TRIG 1.8V

High level triggers the ON

status.

It is pulled up by an internal

200 Kresistor.

Ground it if you do not use it.

UART

UART2_TXD 46 DO UART data transmit VOL max=0.45V;

VOH min=1.35V; 1.8V Data communication

Leave them disconnected if

you do not use them.

UART2_RXD 47 DI UART data receive VIL min=-0.3V; 1.8V

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VIL max=0.45V;

VIH min=1.35V;

VIH max=2.1V

UART2_CTS 51 DI Clear to send VOL max=0.45V;

VOH min=1.35V; 1.8V Leave it disconnected if you

do not use it.

UART2_RTS 52 DO Request to send

VIL min=-0.3V;

VIL max=0.45V;

VIH min=1.35V;

VIH max=2.1V

1.8V Leave it disconnected if you

do not use it.

UIM

VUIM 35 PO UIM power supply output

1.8V USIM:

Vmax = 1.9V ;

Vmin = 1.7V;

3V USIM:

Vmax = 3.05V;

Vmin = 2.7V;

IO max =50mA

1.8V/3V

Compatible with 1.8/3V UIM

card

UIM_RESET 38 DO UIM reset

1.8V USIM:

VOL max = 0.45V;

VOH min = 1.35V;

3V USIM:

1.8V/3V

720 Hardware User Guide

VOL max = 0.4V;

VOH min = 2.6V;

Compatible with 1.8/3V UIM

card

UIM_DATA

36 IO UIM data input, output

1.8V USIM:

VIL max = 0.6V;

VIH min = 1.2V;

VOL max = 0.45V;

VOH min = 1.35V;

3V USIM:

VIL max = 0.8V

VIH min = 1.95V

VOL max = 0.45V

VOH min = 2.6V

1.8V/3V

UIM_CLK 37 DO UIM clock output

1.8V USIM:

VOL max = 0.45V

VOH min = 1.35V

3V USIM:

VOL max = 0.4V

VOH min = 2.6V

1.8V/3V

UIM_DETECT 39 DI UIM detect VIL min = -0.3V

VIL max = 0.63V 1.8V

USB

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USB_DM 41 IO USB data negative signal USB2.0 Used for firmware download

and data transmission

Differential trace for DM and

90 impedance resistance

USB_DP 42 IO USB data positive signal USB2.0

VBUS 40 PI USB voltage test 3.3V~5.2V, typically 5V

USB _ID 43 AI Identify host and device 1.8V Leave it disconnected if you

do not use it.

ADC

ADC2 88 AI

Analog-to-digital signal

conversion

Vmax=1.7V

Vmin=0.1V 1.8V

16-bit, detectable voltage

range: 0.1 V to 1.7 V

ADC1 89 AI

Analog-to-digital signal

conversion

Vmax=1.7V

Vmin=0.1V 1.8V

Network LED Indicator

NET_LIGHT 83 DO Indicate network status VOL max=0.45V;

VOH min=1.35V; 1.8V Leave it disconnected if you

do not use it.

Sleep Mode Control

DTR 79 DI Sleep mode control

VIL min=-0.3V;

VIL max=0.45V;

VIH min=1.35V;

VIH max=2.1V

1.8V Leave it disconnected if you

do not use it.

RING

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RING 13 DO Incoming call ring VOL max=0.45V;

VOH min=1.35V; 1.8V Leave it disconnected if you

do not use it.

Other Pins

FORCE_USB_BOOT 48 DI Force to download and

upgrade control pin

VIL min=-0.3V;

VIL max=0.45V;

VIH min=1.35V;

VIH max=2.1V

1.8V Leave it disconnected if you

do not use it.

ANT_MAIN 76 Main antenna 50  impedance

ANT_GPS 92 GPS antenna 50  impedance

ANT_AUX 94 4Gdiversity aerial 50  impedance

2、3、4、5、

6、7、8、9、

10、11、12、

15、16、18、

19、21、22、

23、24、25、

50、53、54、

55、56、57、

58、59、60、

61、62、63、

64、65、66、

67、68、69、

70、71、72、

NC Leave them disconnected.

Do not use them.

720 Hardware User Guide

73、78、80、

81、82、84、

85、86、87、

90、96

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2.3 Power Control Interfaces

Name Pin I/O Function Remarks

VABT 17/18/1

9 P Main power supply

input 3.3 V to 4.3 V (TYP: 3.8 V )

VDDIO_1P8 45 P 1.8 V power supply

output

Supply power for IO level shifting

circuit.

Load capability: <100 mA

Advise to add ESD to protect while

using.

RESET 32 DI Reset input Low level

PON_TRIG 34 DI PON_TRIG High level triggers the ON status

PWRKEY 33 DI Power ON/OFF Low level triggers the ON status

2.3.1 VBAT

VBAT is the power supply input pin of the module. Its input voltage ranges from 3.3 V to 4.3 V and

the preferable value is 3.8V. In addition to baseband, it supplies power for RF power amplifier.

The performance of the VBAT power supply is a critical path to module's performance and

stability. The peak input current at the VBAT pin can be up to3A when the signal is weak and the

module works at the maximum transmitting power. The voltage will encounter a drop in such a

situation. The module might restart if the voltage drops lower than 3.3 V.

720 Hardware User Guide

Figure 2-2 Current peaks and voltage drops

Figure 2-3 shows the reference design of the VRTC power supply.

Figure 2-3 Capacitors used for the power supply

In Figure 2-3, you can use TVS at D1 to enhance the performance of the module during a burst.

SMF5.0AG (Vrwm=5V&Pppm=200W) is recommended. A large bypass tantalum capacitor (220

F or 100 F) or aluminum capacitor (470 F or 1000 F) is expected at C1 to reduce voltage

drops during bursts together with C2 (10-F ceramics capacitor). It is recommended that you add

0.1 F, 100 pF, and 33 pF filter capacitors to enhance the stability of the power supply.

The module might fail to reset or power on/offin remote or unattended applications, or in an

environment with great electromagnetic interference (EMI). A controllable power supply is

720 Hardware User Guide

preferable if used in harsh conditions. You can use the EN pin on the LDO or DC/DC chipset to

control the switch of the power supply as shown inFigure 2-4if a 5V power supply is used.

MIC29302WU in Figure 2-4 is an LDO and outputs 3 A current to ensure the performance of the

module.

Figure 2-4 Reference design of power supply control

The alternative way is to use an enhancement mode p-MOSFET to control the module's power,

as shown inFigure 2-5. When the external MCU detects the exceptions such as no response

from the module or the disconnection of GPRS, power off/on can rectify the module exceptions.

InFigure 2-5, the module is turned on when PWR_EN is set to high level.

Figure 2-5 Reference design of power supply controlled by p-MOSFET

720 Hardware User Guide

Q2 is added to eliminate the need for a high enough voltage level of the host GPIO. In case that

the GPIO can output a high voltage greater than VCCIN - |VGS(th)|, where VGS(th) is the Gate

Threshold Voltage, Q2 is not needed.

Reference components:

 Q1 can be IRML6401 or low Rds(on) pMOSFET, which has higher, withstand voltage and

drain current.

 Q2: a common NPN tripolar transistor, e.g. MMBT3904; or a digital NPN tripolar transistor,

e.g. DTC123. If digital tripolar transistor is used, delete R1 and R2.

 C3: 470-F tantalum capacitor rated at 6.3V, or 1000 F aluminum capacitor. If lithium

battery is used to supply power, C3 can be 220-F tantalum capacitor.

Power Supply Protection

Add TVS diodes (VRWM=5 V) on the VBAT power supply, especially in automobile applications.

For some stable power supplies, Zener diodes can decrease the power supply overshoot.

SMF5.0AG from ONSEMI is an option.

Line Rules

The width of primary loop lines for VBAT on PCB must be able to support the safe transmission of

2 A current and ensure no obvious loop voltage decrease. Therefore, the loop line width of VBAT

is required 2 mm and the ground level should be as complete as possible.

Separation

The module works in burst mode that generates voltage drops on power supply. Furthermore,

this results in a 217Hz TDD noise through power (One of the way generating noise. Another way

is through RF radiation). Analog parts, especially the audio circuits, are subjected to this noise,

known as a "buzz noise" in GSM systems. To prevent other parts from being affected, it is better

to use separated power supplies. The module shall be supplied by an independent power, like a

DC/DC or LDO. SeeFigure 2-6.

DC/DC or LDO should output rated peak current larger than 2 A.

The inductor used in Reference Design (b), should be a power inductor and have a very low

resistance. The value of 10 H, with average current ability greater than 1.2A and low DC

resistance, is recommended.

720 Hardware User Guide

Figure 2-6 Reference designs of separated power supply

Never use a diode to make the drop voltage between a higher input and module power.

Otherwise, Neoway will not provide warranty for product issues caused by this. In this situation,

the diode will obviously decrease the module performances, or result in unexpected restarts, due

to the forward voltage of diode will vary greatly in different temperature and current.

EMC Considerations for Power Supply

Place transient overvoltage protection components like TVS diode on power supply, to absorb

the power surges. SMAJ5.0A/C could be a choice.

2.3.2 VDDIO_1P8

VDDIO_1P8 supports output voltages of 1.8V. It is recommended that VDDIO_1.8V@100mAbe

used only for interface level shifting and to add ESD to protect while using.

2.3.3 ON/OFF

Power-On

After powering on the VBAT pin, you can use PWRKEY to start the module by inputting low-level

pulse for 100 ms (200 ms is recommended). This pin is pulled up by 200 internally. Its typical

high-level voltage is 1.8 V. The following circuit Figure 2-7 or Figure 2-8 is recommended to

control PWRKEY.

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Figure 2-7 Push switch controlling

Figure 2-8 MCU controlling

If the module is powered on but the power-on sequence has not been completed, the states of

each pin are uncertain. The power-on sequence of the module is shown in Figure 2-9.

Figure 2-9 N720 power-on/off sequence

If your application does not require ON/OFF control, you can pull the PWRKEY pin down to GND

through 1.5K resistor. Then the module can start automatically after it is powered on. If you do

720 Hardware User Guide

not use the PWRKEY pin, it must be left disconnected. The PON_TRIG pin can trigger the ON

status of the module by high level.

Power-off

Power off can be achieved through two methods, one is to use PWRKEY input pin; the other is to

use RESET pin.

1. Use PWRKEY pin. Low-level pulse input for 2 seconds can trigger the power-off status of the

module. This pin is pulled up internally. Its typical high-level voltage is 1.8 V. Leave this pin

disconnected if you do not use it.

2. Use RESET pin. Input more than 900ms low pulse when the module is at working status can

trigger the module power off.

If 2.8V / 3.3V IO system is used, it is recommended to use external triode isolation. For details,

refer to Section 2.3.4 RESET Pin Descriptions. Figure 2-10 shows the hard power-off sequence.

Figure 2-10 N720 power-off sequence

2.3.4 RESET

The RESET pin is used to reset and power off the module. It triggers module reset when you

input low-level pulse less than 900ms and the module will power off when input low-level pulse

more than 900ms. (One second is recommended.). This pin is pulled up internally. Its typical

720 Hardware User Guide

high-level voltage is 1.8 V. Leave this pin disconnected if you do not use it. If you use a 2.8V/3.3V

IO system, it is recommended that you add a triode to separate it. Refer to the following design.

Figure 2-11 Reset controlled by button

Figure 2-12 Reset circuit with triode separating

In a circuit shown in Figure 2-12, VDD_EXT=2.8V/3.3V/3.0V, R2=4.7K, R3=47K. Figure 2-13

shows the reset sequence.

Figure 2-13 N720 reset sequence

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2.4 USB Interface

Name Pin I/O Function Remarks

VBUS 40 P USB voltage test 3.3V~5.2V, typically 5V

USB_DM 41 IO USB data negative

signal USB2.0, used for firmware

download and data transmission

USB_DP 42 IO USB data positive

signal

You can download programs for N720 and establish data communication for commissioning

through the USB interface. If the module is used only as USB Device, the recommended USB

circuit is shown in Figure 2-14.

Figure 2-14 USB circuit

Micro USB

VBUS

22PF

ESD9X5VU

PESD5V0S1BL

DNI-18PF

0Ω

USB_DM

USB_DP

1UF

Parallel a 1F and 22pF filter capacitors to the VBUS pin as close to the pin as possible. TVS

components are required for the VBUS power line. The junction capacitance of the TVS

protection diodes for USB_DP and USB_DM should be lower than 12pF as possible. USB data

720 Hardware User Guide

lines adopt differential trace design, in which the differential impedance is limited to 90 

characteristics impedance. Isolate the traces from other signal traces.

2.5 UIM Card Interface

Name Pin I/O Function Remarks

VUIM 35 PO UIM power supply output Compatible with 1.8/3 V

UIM card

UIM_DATA 36 IO UIMdata I/O

A 10K resistor is required

between VUIM and

UIM-DATA.

UIM_CLK 37 DO UIMclock output

UIM_RESET 38 DO UIMreset

UIM_DETECT 39 DI UIM detect Advise to use a pull-up

resistor

N720 supports 1.8V/3V UIM cards.. VUIM is the power supply pin of the UIM card and its

maximum load is 30 mA. The UIM_DATA pin is not pulled up internally, so you need to reserve

external pull-up resistor in your design. UIM_CLK is the clock signal pin, supporting 3.25 GHz of

clock frequency. Figure 2-15 shows the reference design of the UIM card interface.

Figure 2-15 Reference design of SIM card interface

720 Hardware User Guide

ESD protectors, such as ESD diodes or ESD varistors (with a junction capacitance of less than

33 pF), are recommended to be added on the SIM signals, especially in automotive electronics or

other applications with badly ESD. Replace the ESD diodes with 27 pF to 33 pF capacitors

connecting to GND in common applications. The ESD diodes or small capacitors should be close

to UIM card.

N720 supports SIM card detection. UIM_DETECT is 1.8V interrupt pins. Low level means UIM

card detected while high level mean no UIM card detected.

If you apply N720 to some electric terminals, MUP-C713(H2.8) is recommended.

Figure 2-16 Encapsulation

The antenna should be installed far away from the UIM card and UIM card traces, especially to

the build-in antenna.

The UIM traces on the PCB should be as short as possible and shielded with GND copper.

The ESD protection diodes or small capacitors should be close to UIM card on the PCB.

720 Hardware User Guide

2.6 GPIO

N720supports UART. You can configure the GPIO to meet your requirements for connecting to

different devices. For the open multi-function GPIO interface, please inquiry our technical support

engineers. The level of the module interface is 1.8 V. Table 2-3lists GPIO pins.

Table 2-3 GPIO

Name Pin I/O Function Remarks

UART2_TXD 46 DO UART data transmit

Data communication

UART2_RXD 47 DI UART data receive

UART2_CTS 51 DI Clear to send

UART2_RTS 52 DO Request to send

ADC2 88 AI ADC2input 16-bit, detectable voltage

range: 0.1 V to 1.7 V

ADC1 89 AI ADC1input

NET_LIGHT 83 DO Indicate network status

DTR 79 DI Sleep mode control

RING 13 DO Incoming call ring

1.1.1 UART

N720 provides one group of UART interfaces, which support hardware flow control and 4Mbps at

most. The high level is 1.8V. Figure 2-17 shows the reference design of the UART interface.

720 Hardware User Guide

Figure 2-17 Reference design of the UART interface

If the UART does not match the logic voltage of the MCU, it is recommended that you add a level

shifting circuit outside of the module as shown in Figure 2-18.

Figure 2-18 Recommended level shifting circuit

720 Hardware User Guide

Components:

R2/R4: 2K-10K. The greater the UART baud rate is, the lower the R2 value is.

R1/R3: 4.7K-10K The greater the UART baud rate is, the lower the R3 value is.

Q1: MMBT3904 or MMBT2222 High-speed transistor is better.

MCU_UTXD and MCU_URXD are respectively the TX and RX ports of the MCU while TXD and

RXD are respectively the TX and RX ports of the module.

Voltage at VCC_IO is the voltage at the UART of the MCU while voltage at VDDIO_1V8 is the

voltage at the UART of the module.

2.6.2 ADC

N720 provides two ADC channels, and the input voltage ranges from 0.1 to 1.7V. ADC pin

supports highest precision of 16-bit and it can be used for temperature and other check. If you

apply this pin to SIM card temperature check on electric terminals, refer to Neoway GPRS

Module ADC User Guide.

2.6.3 NET_LIGHT

NET_LIGHT can output 1.8 V high level and is forbidden to be used to drive the LED indicator.

Users can drive the LED with a transistor instead, as shown in Figure 2-18.

Figure 2-19 LED indicator driven by transistor

720 Hardware User Guide

When the module is running, the LED indicator is driven by the NET_LIGHT pin to indicate

different module status with its various blink behaviors. N720 supports multiple blink style and

you can configure it using AT commands.

2.6.4 DTR

Generally, DTR is used to control sleep mode together with AT commands. Enable the sleep

mode function by AT command. Then pulling DTR low will bring the module into sleep mode if the

module is idle. In this mode, the idle current is less than 4 mA, depending on the DRX setting of

network.

In sleep mode, the module can respond to the incoming call, SMS, and GPRS data. The host

MCU can also control the module to exit sleep mode by controlling DTR.

Process of entering sleep mode:

1. Keep DTR high level in normal working mode. Activate the sleep mode by using the

AT+ENPWRSAVE=1 command.

2. Pull DTR low, and the module will enter sleep mode, but only after process and pending data

finished.

3. In sleep mode, the external MCP can pull DTR high so that the module will exit from sleep

mode actively. Then the module can transmit data and initiate calls. After processing is

finished, pull DTR low again to take the module back to sleep mode.

4. In sleep mode, the module can be woken up by the events of incoming voice call, received

data, or SMS. Meanwhile the module will send out the unsolicited messages through the

UART.

Upon receipt of the unsolicited messages, the host MCU should pull DTR high firstly,

otherwise the module will resume sleep mode in two minutes after the service processing.

Then the host MCU can process the voice call, received data, or SMS. After processing is

finished, pull DTR low again to put the module into sleep mode.

2.6.5 RING Signal Indicator

 Calling: Once a voice call is incoming, UART outputs "RING" character strings and

meanwhile the RING pin outputs 30 ms low pulses at 5s period. After the call is answered,

the high level restores.

720 Hardware User Guide

Figure 2-20 RING indicator for incoming call

 SMS: Upon receipt of SMS, the module outputs one 35 ms low pulse.

Figure 2-21 RING indicator for SMS

2.7 Commissioning Interfaces

To facilitate software update and commissioning, reserve the commissioning interfaces.

2.7.1 FORCE_USB_BOOT

The module can enter the fastboot mode by short connecting the FORCE_USB_BOOT pin and

VDDIO_1P8V during the startup. This is the last method to troubleshoot the abnormality that the

module cannot start or operation properly.

Figure 2-22 Reference design of the fast boot interface

30 ms 30 ms

35 ms

720 Hardware User Guide

3 RF Interface

Name Pin I/O Function Remarks

ANT_MAIN 76 AI/O 2G/3G/4G main antenna

50 characteristic

impedance

ANT_GPS 92 AI GPS antenna

ANT_AUX 94 AI 4Gdiversity aerial

3.1 2G/3G/4G RF Design and PCB Layout

ANT_MAIN and ANT_AUX is the antenna pin of N720. A 50  antenna is required. VSWR

ranges from 1.1 to 1.5. The antenna should be well matched to achieve best performance. It

should be installed far away from high-speed logic circuits, DC/DC power, or any other strong

disturbing sources.

A 50  antenna is required. VSWR ranges from 1.1 to 1.5. The antenna should be well matched

to achieve best performance.

For multiple-layer PCB, the trace between the antenna pad of module and the antenna connector,

should have a 50  characteristic impedance, and be as short as possible. The trace should be

surrounded by ground copper. Place plenty of via holes to connect this ground copper to main

ground plane, at the copper edge.

For dual-layer PCB, the width of recommended impedance trace is 0.8 mm to 1 mm and the

grounding copper should away from the trace for 1 to 1.5 time of the trace width.

If the trace between the module and connector has to be longer, or built-in antenna is used, a

-type matching circuit is needed, as shown in Figure 3-1.

Figure 3-1 Reference of antenna matching design

720 Hardware User Guide

Big RF solder pad can result in great parasitic capacitance, which will affect the antenna

performance. Remove the copper on the first and second layers under the RF solder pad.

Figure 3-2 Recommended RF PCB design

If you adopt RF antenna connections, the GSC RF connector MM9329-2700RA1 from Murata is

recommended..Figure 3-3shows the encapsulation specifications.

Figure 3-3 Encapsulation specifications of Murata RF connector

RF antenna can also be connected to the module by soldering. In this manner, you must ensure

proper soldering in case of damage that lowers RF performance. Figure 3-4shows the pictures of

these two connections.

Figure 3-4 RF connections

720 Hardware User Guide

3.2 GPS RF Design and PCB Layout

3.2.1 GPS Impedance

The 92nd pin is the GPS interface of the module, which also requires a 50 . The PCB layout for

GPS is similar to that for GPRS. For details, refer to the previous section. Figure 3-5 shows the

internal structure of the GPS RF.

Figure 3-5 GPS RF structure

In addition to the basic rules, the GPS routing has higher requirements because the air wireless

GPS signal has lower strength, which results in weaker electrical signal after the antenna

receives. Weaker signals are more susceptible to interference. Therefore, active antenna are

commonly used for GPS. The active GPS antenna amplifies the weak signals received to

stronger signals through the low-noise amplifier (LNA) and then transmits the signals through the

feeder.

If you use a passive antenna, add LNA near the feeder because the module does not embed

one.

If the antenna and layout are not designed reasonably, the GPS will be insensitive, resulting in

long time on positioning or inaccurate position.

Keep the GPRS and GPS far away from each other in layout and antenna layout.

3.2.2 Active GPS Antenna Design

Ceramic GPS chip antenna is monly used. In general, it is recommended that you use the active

ceramic antenna. After the antenna receives GPS satellite signals, the LNA amplifies them first

and then they are transmitted to the 92nd pin (GPS_ANT) through the feeder and PCB traces.

50 resistance is required for both the feeder and PCB traces and the traces should be as short

720 Hardware User Guide

as possible. The power supply of the active antenna is fed by the 100 nH inductance through the

signal traces.

Common active antenna requires 3.3V to 5V power supply. Though the active antenna has a low

power consumption, it requires stable and clean power supply. You are advised to use

high-performance LDO to supply power for the antenna through a 100 nH inductance, as shown

inFigure 3-6.

Figure 3-6 Power supply reference for active antenna

It is recommended that you add an ESD protection diode to the antenna interface in an

environment with great electromagnetic interference and other applications with badly ESD. The

ESD protection diode must have ultra-low capacitance (lower than 0.5 pF). Otherwise, it will

affect the impedance of the RF loop or result in attenuation of RF signals. RCLAMP0521P from

Semtech or ESD5V3U1U from Infineon is recommended.

On the PCB, keep the RF signals and RF components away from high-speed circuits, power

supplies, transformers, great inductors, the clock circuit of single-chip host, etc.

720 Hardware User Guide

4 Electric Feature and Reliability

4.1 Electric Feature

Table 4-1 N720 Electric Feature

Module Status Minimum Value Typical Value Maximum Value

VBAT

Vin 3.3V 3.8V 4.3V

Iin / / 3A

If the voltage is too low, the module might fail to start. If the voltage is too high or there is a

voltage burst during the startup, the module might be damaged permanently.

If you use LDO or DC-DC to supply power for the module, ensure that it output at least 3 A

current.

4.2 Temperature

Table 4-2 Temperature Feature

Module Status Minimum Value Typical Value Maximum Value

Work -40°C 25°C 85°C

Limit -40°C 85°C

Storage -40°C 85°C

If the module works in temperature exceeding the thresholds, its RF performance might be worse

but it can still work properly.

720 Hardware User Guide

4.3 ESD Protection

Electronics need to pass sever ESD tests. The following table shows the ESD capability of key

pins of our module. It is recommended that you add ESD protection to those pins in accordance

to the application to ensure your product quality when designing your products.

Humility: 45%Temperature: 25°C

Table 4-3 N720 ESD feature

Testing Point Contact Discharge Air Discharge

VBAT ±8KV ±15KV

GND ±8KV ±15KV

ANT ±8KV ±15KV

Cover ±8KV ±15KV

Others ±2KV ±4KV

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5 RF Feature

5.1 Work Band

Table 5-1 N720 work band

Work band Uplink Downlink

GSM850 824~849MHz 869~894MHz

PCS1900 1850~1910MHz 1805~1880MHz

UMTS B2 1850~1910MHz 1805~1880MHz

UMTS B4 1710~1755MHz 2110~2155MHz

UMTS B5 824~849MHz 869~894MHz

LTE-FDD B2 1850~1910MHz 1805~1880MHz

LTE-FDD B4 1710~1755MHz 2110~2155MHz

LTE-FDD B5 824~849MHz 869~894MHz

LTE-FDD B7 2500~2570MHz 2620~2690MHz

LTE-FDD B12 699.7 – 715.3 MHz 729.7– 745.3 MHz

LTE-FDD B17 704~716MHz 734~746MHz

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5.2 TX Power and RX Sensitivity

Table 5-2 N720 RF power and RX sensitivity

Band Transmitting Power Receiving Sensitivity

GSM850 34 dBm <-108 dBm

PCS1900 31.5 dBm <-108 dBm

UMTS B2 24 dBm <-108 dBm

UMTS B4 24 dBm <-108 dBm

UMTS B5 24 dBm <-108 dBm

LTE-FDD B2 23 dBm <-95 dBm

LTE-FDD B4 23 dBm <-97 dBm

LTE-FDD B5 23 dBm <-95 dBm

LTE-FDD B7 23 dBm <-95 dBm

LTE-FDD B12 23 dBm <-95 dBm

LTE-FDD B17(10MHz) 23 dBm <-95 dBm

All the values above are obtained in the lab environment. In your actual applications, there

might be a difference because of the network environment.

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6 Mechanical Feature

6.1 Dimensions

Figure 6-1 Dimensions of N720

720 Hardware User Guide

6.2 PCB Foot Print

Figure 6-2 N720PCBFoot Print(Top View)

A test point is reserved at the Silk Area. It is recommended that you add a layer of white ink in

case short circuit. Do not lay out any trace under the JTAG pin.

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7 Mounting and Packaging

7.1 Mounting the Module onto the Application Board

N720 is compatible with industrial standard reflow profile for lead-free SMT process.

The reflow profile is process dependent, so the following recommendation is just a start point

guideline:

 Only one flow is supported.

 Quality of the solder joint depends on the solder volume. Minimum of 0.12 mm to 0.15stencil

thickness is recommended.

 Use bigger aperture size of the stencil than actual pad size.

 Use a low-residue, no-clean type solder paste.

For information about cautions in N720 storage and mounting, refer to Neoway Module Reflow

Manufacturing Recommendations.

When you maintain and manually solder it, use heat guns with great opening, adjust the

temperature to 250 degrees (depending on the type of the solder paste), and heat the module till

the solder paste is melt. Then remove the module using tweezers. Do not shake the module in

high temperature when you remove it. Otherwise, the components inside the module might be

misplaced.

7.2 Package

N720 modules are packaged in sealed bags on delivery to guarantee a long shelf life. Package

the modules again in case of opening for any reasons.

If exposed in air for more than 48 hours at conditions not worse than 30°C/60% RH, a baking

procedure should be done before SMT. Or, if the indication card shows humidity greater than

20%, the baking procedure is also required. Do not bake modules with the package tray directly.

720 Hardware User Guide

8 SMT TemperatureCurve

Figure 8-1 Temperature curve

X: Time (s) Y Temperature (°C)

Technicalparameters:



Ramp up rate: 1to 4°C/sec; Ramp down rate: -3 to-1°C/sec



Soaking zone: 150-180°CTime: 60-100s



Reflow zone:>220°CTime: 40-90s



Peak temperature: 235-250°C

It is not recommended that you use the kind of solder paste different from our module technique.



The melting temperature of solder paste with lead is 35°Clower than that of solder paste

without lead. It is easy to cause faulty joints for BGA inside the module after second reflow

soldering.



If you can use only solder pastes with lead, please ensure that the reflow temperature is kept

at 220°C for more than 45 seconds and the peak temperature reaches 240°C.

Neoway will not provide warranty for heat-responsive element abnormalities caused by improper

temperature control.

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9 Abbreviations

nalog-Digital Converter

CPU Central Processing Unit

DTR Data Terminal Ready

EGSM Enhanced GSM

ESD Electronic Static Discharge

GPRS General Packet Radio Service

GSM Global Standard for Mobile Communications

IMEI International Mobile Equipment Identity

LED Light Emitting Diode

PCB Printed Circuit Board

RF Radio Frequency

SIM Subscriber Identification Module

UART Universal asynchronous receiver-transmitter

N720 Hardware User Guide

FCC Information

This equipment has been tested and found to comply with the limits for a Class B digital device,

pursuant to part 15 of the FCC rules. These limits are designed to provide residential protection

against harmful interference in a residential installation. This equipment generates, uses and can

radiate radio frequency energy and, if not installed and used in accordance with the instructions,

may cause harmful interference to radio communications. However, there is no guarantee that

interference will not occur in a particular installation. If this equipment does cause harmful

interference to radio or television reception, which can be determined by turning the equipment

off and on. The user is encouraged to try to correct the interference by one or more of the

following measures:

Reorient or relocate the receiving antenna.

Increase these paration between the equipment and receiver.

Connect the equipment into an outlet on the circuit different from that to which the receiver is

connected.

Consult the dealer or an experienced radio/TV technician for help.

CAUTION!

The manufacturer is not responsible for any radio or TV interference caused by unauthorized

modifications to this equipment. Such modifications could void the user authority to operate the

equipment.

If the FCC identification number is not visible when the module is installed inside another device,

then the outside of the device into which the module is installed must also display a label

referring to the enclosed module. This exterior label can use wording such as the following:

“Contains Transmitter Module FCC ID: PJ7-1705 Or Contains FCC ID: PJ7-1705”

FCC RADIATION EXPOSURE STATEMENT

This equipment complies with FCC RF radiation exposure limits set for an uncontrolled

environment. This transmitters must not be co-located or operating in conjunction with any other

antenna or transmitter. This device complies with part 15 of the FCC rules. Operation is subject

to the following two conditions: (1)This device may not cause harmful interference, and (2) This

device must accept any interference, including interference that may cause undesired operation.

The distance between user and product include antenna should be no less than 25 cm.

The maximum permissible antenna gain is 0 dBi for each band, and under no conditions may

an antenna gain be used that would exceed the ERP and EIRP power limits as specified in

Parts 22, 24 and 27.

Neoway Technology 1705 LTE Module User Manual

Shenzhen Neoway Technology Co., Ltd LTE Module

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