AX995 Datasheet. Www.s Manuals.com. R1.1 Axelite
User Manual: Datasheets AX995, AX995SA.
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AX995 1.6X Linear Fan Driver with VO Fully On Control GENERAL DESCRIPTION The AX995 is a low dropout linear regulator which is designed to power a DC fan and delivers up to 600mA output current. The output voltage follows the 1.6 times of VSET voltage and typical dropout voltage is only 150mV (typical) at 600mA output current. The VSET voltage must be larger than 1V to guarantee V O 1.6 times of VSET. A FON pin turns VO output fully on when given low. The features of current limit (with fold back current) and over temperature protection protect the device against current over-loads and over temperature. The AX995 is available in a SOP-8 package. FEATURES - Low Dropout Voltage: 150mV@0.6A VO Follows 1.6 times of VSET - FON Pin to Turn VO Fully On Stable with Low ESR Ceramic Capacitors Current-Limit and Thermal Shutdown Protection SOP-8 Pb-Free Package BLOCK DIAGRAM VO VIN Current Limit and Short Protection - + Error Amp Thermal Shutdown FON VO Fully On Logic GND VSET 1/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 AX995 PIN ASSIGNMENT AX995 The package of AX995 is SOP-8L; the pin assignment is given by: Name Description ( Top View ) GND GND pin VIN IC power supply pin FON 1 8 GND Output Pin. Its voltage is 1.6 times of VO VSET 7 GND VIN 2 This pin sets the output voltage. Its 6 GND VSET voltage must be larger than 1V to VO 3 guarantee VO 1.6 times of VSET 5 GND VSET 4 FON Input. Pulling this pin below 0.4V FON turns the regulator fully on. Internally SOP-8L pulled high. ORDER/MARKING INFORMATION Order Information AX995 X X Package Type S : SOP-8L Top Marking 9 9 5 AX Y Y WW X Logo Part number ID code:internal Packing WW: 01~52 Year: 10=2010 11=2011 Blank : Tube A : Taping ABSOLUTE MAXIMUM RATINGS (at TA=25°C) Characteristics Symbol Rating Unit VIN Supply Voltage VIN -0.3 to 6.5 V FON Input Voltage VFON -0.3 to VIN V VSET Voltage VSET -0.3 to VIN V Power Dissipation PD Internally limited W Storage Temperature Range TST -65 to +150 °C Junction Temperature Range TJ -40 to 125 °C Operating Temperature Range Thermal Resistance from Junction to case TOP θJC -40 to +85 20 °C °C/W Thermal Resistance from Junction to ambient θJA 60 °C/W Note: θJA is measured with the PCB copper area approximately 1.5 in2 (Multi-layer) 2/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 AX995 ELECTRICAL CHARACTERISTICS (VSET=2V, VIN=5V, IOUT= 0.5A, CIN=COUT=2.2uF, TA=25°C unless otherwise specified) Characteristics Symbol VIN Supply Voltage Range VIN Quiescent Current ICCQ Output Voltage/VSET Voltage VO/VSET Line Regulation Load Regulation Output Resistance RDS(ON) Current Limit ILimt Short Circuit Current IShort Minimum VSET Voltage VSET Pin Current FON Pin Logic Threshold Voltage Conditions VO=5V, No Load VIN=5.5V, VSET=1V~3.2V VIN=4.5V to 5.5V IOUT =10mA ~ 0.6A IOUT=0.6A, VSET=3.4V 4.5 - 5.5 V - 70 - uA 1.552 1.6 1.648 V/V - 0.2 0.5 % - 0.2 0.5 % - 240 320 mΩ - 1 - A - 0.5 - A VSET - 1 - V ISET - 80 200 Vo<0.6V nA VFON-H Normal Operating 2.0 - - VFON-L Regulator Fully On - - 0.8 - 1 5 uA - 140 - °C - 30 - °C FON Pin Bias Current IFON Thermal shutdown Temp TSD FON =0V Thermal Shutdown Hysteresis Min Typ Max Units V APPLICATION CIRCUIT U1 VIN=5V 2 VSET C1 2.2uF FON 4 1 VIN VO Vo=1.6 X VSET 3 VSET FON GND 5,6,7,8 C2 2.2uF FAN AX995 3/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 AX995 FUNCTION DESCRIPTIONS Output Voltage Regulation The Output Voltage is set by VSET voltage. VO output voltage follows the 1.6 times of VSET voltage until it reaches VIN voltage. Fully-On Control If the FON pin logic level smaller than 0.8V, the output voltage can be promoted near to VIN voltage. Otherwise, VOUT is normal operating by FON larger than 2.0V. Current-Limit The AX995 monitors the current via the output PMOS and limits the maximum current to prevent load and AX995 from damages during overload or short circuit conditions. Short Current Protection When the output voltage drops below 0.6V (typical), which is caused by over load or short circuit, the fold back current limit circuitry limits the output current to 500mA. The fold back current limit is used to reduce the power dissipation during short circuit condition. Thermal Shutdown A thermal shutdown circuit limits the junction temperature of AX995. When the junction temperature exceeds +140°C, a thermal sensor turns off the output PMOS, allowing the device to cool down. The regulator regulates the output again through initiation of a new soft-start cycle after the junction temperature cools by 30°C, resulting in a pulsed output during continuous thermal overload conditions. 4/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 AX995 APPLICATION INFORMATION Capacitor Selection Normally, use a 2.2µF capacitor on the input and a 2.2µF capacitor on the output of the AX995. In order to insure the circuit stability, the proper output capacitor value should be larger than 1uF. With X5R and X7R dielectrics, 2.2uF is sufficient at all operating temperatures. Thermal Considerations The AX995 series can deliver a current of up to 500mA over the full operating junction temperature range. However, the maximum output current must be dated at higher ambient temperature to ensure the junction temperature does not exceed 125°C. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Power dissipation can be calculated based on the output current and the voltage drop across regulator. PD = (VIN - VO) IO The final operating junction temperature for any set of conditions can be estimated by the following thermal equation: PD (MAX) = (TJ (MAX) - TA) / θJA Where TJ (MAX) is the maximum junction temperature of the die (125°C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance (θJA) for SOP-8L package at recommended minimum footprint is 60°C/W. Visit our website in which “Recommended Footprints for Soldering Surface Mount Packages” for detail. PCB Layout 1. Please place the input capacitors close to the V IN 2. Ceramic capacitors for load must be placed near the load as close as possible 3. To place AX995 and output capacitors near the load is good for performance. 4. Large current paths that VIN and Output lines must have wide tracks. 5. GND connect large copper area can reduced IC temperature. 5/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 AX995 TYPICAL CHARACTERISTICS VSET VS ICCQ ICCQ (uA) ICCQ (uA) VIN VS ICCQ 200 180 160 140 120 100 80 60 40 20 0 IOUT=0A 3 3.5 4 4.5 5 VIN (V) 5.5 200 180 160 140 120 100 80 60 40 20 0 0 6 4 VOUT (V) VOUT (V) 5 3 2 1 IOUT=100A VIN=5.5 0 1 1.5 2 2.5 1 1.5 3 3.5 4 4 0℃ 25℃ 50℃ 75℃ 100℃ 125℃ Temperaute VS FON Voltage FON Voltage (V) Output Resistance (m Ω) 3.5 VSET=1V IOUT=200mA -40℃ -25℃ Temperaute VS Output Resistance VIN=5V VSET=3.5V IOUT=500mA 25℃ 50℃ 3 Temperature(℃) 500 450 400 350 300 250 200 150 100 50 0 0℃ 2.5 1.70 1.68 1.66 1.64 1.62 1.60 1.58 1.56 1.54 1.52 1.50 VSET (V) -40℃ -25℃ 2 Temperaute VS VOUT VSET VS VOUT 0.5 0.5 VSET (V) 6 0 IOUT=0A 75℃ 100℃ 125℃ Temperature(℃) 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 VFON-H VFON-L -40℃ -25℃ 0℃ 25℃ 50℃ 75℃ 100℃ 125℃ Temperature(℃) 6/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 AX995 TYPICAL CHARACTERISTICS (CONTINUOUS) Power ON Power ON Fully-On Fully-On(VIN Drop) Load Transient Load Transient (VIN Drop) 7/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 AX995 H PACKAGE OUTLINES E θ L DETAIL A b D e y A1 C A A2 7 (4X) Dimensions in Millimeters Min. Nom. Max. A 1.75 A1 0.1 0.25 A2 1.25 C 0.1 0.2 0.25 D 4.7 4.9 5.1 E 3.7 3.9 4.1 H 5.8 6 6.2 L 0.4 1.27 b 0.31 0.41 0.51 e 1.27 BSC y 0.1 O θ 0 8O Mold flash shall not exceed 0.25mm per side JEDEC outline: MS-012 AA Symbol DETAIL A Dimensions in Inches Min. Nom. Max. 0.069 0.04 0.1 0.049 0.0075 0.008 0.01 0.185 0.193 0.2 0.146 0.154 0.161 0.228 0.236 0.244 0.015 0.05 0.012 0.016 0.02 0.050 BSC 0.004 O 0 8O 8/8 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.1 Aug.25, 2010 www.s-manuals.com
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