Tiny Serial Digital Thermal Sensor Tc74 Microchip

User Manual: Marking of electronic components, SMD Codes U6, U6*, U6**. Datasheets BZX84J-C33, CZRF3V6B-HF, TC74A6-5.0VCT, XC6215B372NR.

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TC74

Tiny Serial Digital Thermal Sensor
Features

General Description

• Digital Temperature Sensing in SOT-23-5 or
TO-220 Packages
• Outputs Temperature as an 8-Bit Digital Word
• Simple SMBus/I2C™ Serial Port Interface
• Solid-State Temperature Sensing:
- ±2°C (max.) Accuracy from +25°C to +85°C
- ±3°C (max.) Accuracy from 0°C to +125°C
• Supply Voltage of 2.7V to 5.5V
• Low Power:
- 200 µA (typ.) Operating Current
- 5 µA (typ.) Standby Mode Current

The TC74 is a serially accessible, digital temperature
sensor particularly suited for low cost and small formfactor applications. Temperature data is converted from
the onboard thermal sensing element and made
available as an 8-bit digital word.

Applications
• Thermal Protection for Hard Disk Drives
and other PC Peripherals
• PC Card Devices for Notebook Computers
• Low Cost Thermostat Controls
• Power Supplies
• Thermistor Replacement

Package Types

Communication with the TC74 is accomplished via a 2wire SMBus/I2C compatible serial port. This bus also
can be used to implement multi-drop/multi-zone
monitoring. The SHDN bit in the CONFIG register can
be used to activate the low power Standby mode.
Temperature resolution is 1°C. Conversion rate is a
nominal 8 samples/sec. During normal operation, the
quiescent current is 200 µA (typ). During standby
operation, the quiescent current is 5 µA (typ).
Small size, low installed cost and ease of use make the
TC74 an ideal choice for implementing thermal
management in a variety of systems.

Functional Block Diagram

Internal Sensor
(Diode)

TO-220

SOT-23
SDA

SCLK

5

4

SCLK

∆Σ Modulator

TC74

Control

Logic

TC74

123 45

NC
SDA
GND
SCLK
VDD

SDA
Serial Port
Interface

1

2

3

NC

GND

VDD

Temperature
Register

Note: The TO-220 tab is connected
to pin 3 (GND)

 2002 Microchip Technology Inc.

DS21462C-page 1

TC74
1.0

ELECTRICAL
CHARACTERISTICS

1.1

Absolute Maximum Ratings†

Supply Voltage (VDD) ............................................ +6V
Voltage On Any Pin ....... (GND – 0.3V) to (VDD + 0.3V)
Current On Any Pin .......................................... ±50 mA

† Notice: Stresses above those listed under "Maximum Ratings" may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions
above those indicated in the operation listings of this
specification is not implied. Exposure to maximum rating conditions for extended periods may affect device
reliability.

Operating Temperature (TA) ........ -40°C ≤ TA ≤ +125°C
Storage Temperature (TSTG) .............. -65°C to +150°C
Junction Temperature (TJ)................................ +150°C

DC CHARACTERISTICS
Electrical Specifications: Unless otherwise noted, VDD = 3.3V for TC74AX-3.3VXX and
VDD = 5.0V for TC74AX-5.0VXX, -40°C ≤ TA ≤ 125°C. Note 5
Parameters

Sym

Min

Typ

Max

Units

Conditions

Power-on Reset Threshold

VPOR

1.2

—

2.2

V

VDD Falling Edge or Rising
Edge

Supply Voltage

VDD

2.7

—

5.5

V

Note 5

Operating Current

IDD

—

200

350

µA

VDD = 5.5V, Note 1

IDD-STANDBY

—

5.0

10

µA

VDD = 3.3V
Serial Port Inactive, Note 4

TERR

-2.0
-3.0
—

—
—
±2.0

+2.0
+3.0
—

°C

+25°C 
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Modify Date                     : 2002:11:01 15:31:03-08:00
Create Date                     : 2002:11:01 11:51:40Z
Subject                         : TC74
Keywords                        : serial, digital, thermal, sensor
Page Count                      : 16
Creation Date                   : 2002:11:01 11:51:40Z
Mod Date                        : 2002:11:01 15:31:03-08:00
Producer                        : Acrobat Distiller 5.0 (Windows)
Author                          : Microchip Technology Inc.
Metadata Date                   : 2002:11:01 15:31:03-08:00
Creator                         : Microchip Technology Inc.
Title                           : Tiny Serial Digital Thermal Sensor
Description                     : TC74
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