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Data Sheet

4-CH Linear Constant Current Sink With Matching AP2502

Oct. 2010 Rev 1. 1 BCD Semiconductor Manufacturing Limited

General Description

The AP2502 is a 4-channel independent linear

current sink with low dropout voltage and perfect

match between each channel. Each channel can

provide 20mA continuous constant current.

In application, there is only one 0.1µF ceramic

capacitor required, and there is no any EMI and

switching noise issue. It is perfect choice for

hand-hold portable system especially based on

Li-ion/Polymer battery powered display module.

The brightness can be controlled and/or adjustable

via simple PWM signal applied to EN pin.

The AP2502 is available with SOT-23-6 and

TSOT-23-6 packages.

Features

• Current Matching Between Each Channel: ±1%

• Low Dropout Voltage: 65mV (Typ.) @ I

LED

20mA

• Maximum Output Current on Each Channel:

20mA

• Ultra-low Quiescent Current: 125µA (Typ.)

• Ultra-low Shutdown Current: 1µA (Max.)

• None EMI and Switching Noise Issue

• Permitted PWM Dimming Frequency up to

• 150kHz

• OTSD Protection

Applications

• Mobile Phone, Smart Phone, PDA

• MP3, MP4, PMP

• Small Size Backlight Module

Figure 1. Package Types of AP2502

SOT-23-6 TSOT-23-6

Summary of content (12 pages)

PAGE 1
Data Sheet 4-CH Linear Constant Current Sink With Matching General Description Features The AP2502 is a 4-channel independent linear current sink with low dropout voltage and perfect match between each channel. Each channel can provide 20mA continuous constant current. • • In application, there is only one 0.1µF ceramic capacitor required, and there is no any EMI and switching noise issue.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Pin Configuration K/KT Package (SOT-23-6/TSOT-23-6) Figure 2. Pin Configuration of AP2502 (Top View) Pin Descriptions P in Number Pin Name Description 1 EN Chip enable pin, active high to permit PWM signal input for brightness control by changing duty cycle 2 GND 3, 4, 5, 6 LED4 to LED1 Oct. 2010 GND LED cathode terminal for channel number Rev 1.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Functional Block Diagram Figure 3. Functional Block Diagram of AP2502 Oct. 2010 Rev 1.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Ordering Information AP2502 - Circuit Type G1: Green Package K: SOT-23-6 KT: TSOT-23-6 TR: Tape & Reel Package Temperature Range SOT-23-6 TSOT-23-6 -40 to 85°C -40 to 85°C Part Number AP2502KTR-G1 AP2502KTTR-G1 Marking ID GEE L7E Packing Type Tape & Reel Tape & Reel BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant and Green.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Recommended Operating Conditions Parameter Symbol Value Min Max Unit Enable Input Voltage VEN 2.0 6.0 V Operating Temperature Range TA -40 85 °C Sink Current ILED 20 mA Electrical Characteristics VIN=3.6V, VF_LED=3.2V, TA = 25°C, unless otherwise specified.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Typical Performance Characteristics 200 200 190 180 170 160 150 140 130 120 110 100 90 80 o 160 TC=25 C 150 o TC=85 C 140 130 120 110 100 90 80 70 70 60 50 -40 LED Open o TC=-40 C 180 Quiescent Current (µA) Quiescent Current (µA) 170 190 LED Open VEN=3V 60 -20 0 20 40 60 80 100 120 140 1 2 3 o Figure 4. Quiescent Current vs. Case Temperature 5 6 7 Figure 5. Quiescent Current vs. Enable Voltage 21.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 120 1.0 110 0.8 100 0.6 90 Current Matching (%) Dropout Voltage (mV) Typical Performance Characteristics (Continued) 80 70 60 50 0.4 0.2 0.0 -0.2 -0.4 40 -0.6 30 -0.8 20 -40 -20 0 20 40 60 80 100 120 VEN=3V VLED=300mV -1.0 -40 140 -20 0 20 o 40 60 80 100 120 140 o Case Temperature ( C) Case Temperature ( C) Figure 8. Dropout Voltage vs. Case Temperature Figure 9. Current Matching vs.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Typical Performance Characteristics (Continued) VEN 2V/div I1 VEN 2V/div I2 ILED 10mA/div ILED 10mA/div Time 2ms/div Time 400µs/div Figure 12. LED Current (Note 2) (VIN=4V, VEN=0 to 3.6V, Duty cycle=50%, fPWM=1kHz) Figure 13. Internal Oscillator Working at Low Frequency (VIN=4V, VEN=0 to 3.6V, Duty cycle=50%, fPWM=0.1kHz) Note 2: Chopper offset-canceling technology is adopted to get good current matching, ILED=[(I1+I2)/2]*duty.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Typical Application Figure 14. AP2502 Typical Application Oct. 2010 Rev 1.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Mechanical Dimensions SOT-23-6 Unit: mm(inch) 0° 2.820(0.111) 8° 3.020(0.119) 0.300(0.012) 0.400(0.016) 6 0.200(0.008) 5 0.300(0.012) 0.600(0.024) 4 Pin 1 Dot by Marking 1 2 3 0.700(0.028)REF 0.950(0.037)TYP 0.000(0.000) 0.150(0.006) 1.800(0.071) 2.000(0.079) 0.100(0.004) 0.200(0.008) 0.900(0.035) 1.450(0.057) MAX 1.300(0.051) Oct. 2010 Rev 1.
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Data Sheet 4-CH Linear Constant Current Sink With Matching AP2502 Mechanical Dimensions (Continued) TSOT-23-6 2.800(0.110) 3.000(0.118) 1.500(0.059) 1.700(0.067) Unit: mm(inch) R0.100(0.004) MIN 0° 8° 2.600(0.102) 3.000(0.118) Pin 1 Dot by Marking 0.370(0.015) MIN 0.950(0.037) BSC 0.100(0.004) 0.250(0.010) 1.900(0.075) BSC 0.250(0.010) BSC GAUGE PLANE 0.700(0.028) 0.900(0.035) 1.000(0.039) MAX 0.000(0.000) 0.100(0.004) Oct. 2010 0.350(0.014) 0.510(0.020) Rev 1.
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BCD Semiconductor Manufacturing Limited http://www.bcdsemi.com IMPORTANT NOTICE IMPORTANT NOTICE BCD Semiconductor BCD Semiconductor Manufacturing Manufacturing Limited Limited reserves reserves the the right right to to make make changes changes without without further further notice notice to to any any products products or or specifispecifications herein. cations herein.