Document
4-Channel Programmable LED Current Sink
PAM2810
Features
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Description
The PAM2810 provides 4 regulated current sinks, capable of sinking up to 40mA current to accommodate 4 white LEDs. It requires no charge pump, has no noise and EMI, and significantly improves the efficiency in Li bettery range. LED brightness can be controlled by PWM techniques. The constant current sink is set with an external sense resistor. Alternatively, a PWM signal applied to the EN pin can vary the anticipated brightness of the LED. The device is in shut down mode when the EN input is logic low. The PAM2810 is available in SOT23-8 and DFN 2 mmX2mm Packages.
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Cost Effective LED Driver Support up to 4 White LEDs Output Current up to 40mA per LED Low Dropout Voltage Ultra Low Quiescent Supply Current: 65 μ A (typ) No Noise and EMI Shutdown Current Less than 1 μ A Over Temperature Protection Small Packages : SOT23-8 and DFN 2mmx2mm Pb-free Package
Applications
n White LED for LCD Display Backlights n White LED Keypad Backlights n 1-Cell Li-Ion Battery-operated Equipment Including PDAs, Hand-held PCs, Cellular Phone
Typical Application Circuit
VIN C1 0.1μF 4 VIN 2 EN
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LED1 8
1
LED2 7 PAM2810 LED3 6 LED4 5 GND 3
ISET
R1 6.2 k
Power Analog Microelectronics , Inc
www.poweranalog.com 08/2008 Rev 1.1
1
4-Channel Programmable LED Current Sink
PAM2810
Typical Application Circuit
V BAT VIN C1 0.1μF 4 VIN 2 LED1 EN PAM2810 1 ISET LED4 GND R1 6.2kΩ 3
R1 6.2k Ω VIN C1 0.1μF 4 VIN 2 LED1 EN PAM2810 1 ISET LED4 GND 3 LED2 LED3
8 7 6 5
8 7 6 5 NC
LED2 LED3
Block Diagram
VIN
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VIN C IN 0.1 μ F
1.22V Ref
LED1 LED2 LED3 LED4
EN ISET
Current Setting Current Sinks
RSET
GND
Power Analog Microelectronics , Inc
www.poweranalog.com 08/2008 Rev 1.1
2
4-Channel Programmable LED Current Sink
PAM2810
Pin Configuration
Top View DFN 2mmX2mm Top View SOT23-8
VIN GND EN ISET
1 2 3 4
8 7 6 5
LED1 LED2 LED3 LED4
ISET EN GND VIN
1
EJXYW
8 7 6 5
LED1 LED2 LED3 LED4
2 3 4
EJ: Product Code X: Internal Code Y: Year W: Week
Pin Number DFN2x2 1 2 3 4 5 6 7 8 SOT23-8 4 3 2 1 5 6 7 8
EJX YW
Name VIN GND EN ISET LED4 LED3 LED2 LED1
Description Input Voltage Ground Enable, Allow PWM Brightness Control, Active High LED Current Adjustment Pin LED4 Cathode Terminal LED3 Cathode Terminal LED2 Cathode Terminal LED1 Cathode Terminal
www.DataSheet4U.com
Power Analog Microelectronics , Inc
www.poweranalog.com 07/2008 Rev 1.1
3
4-Channel Programmable LED Current Sink
PAM2810
Absolute Maximum Ratings
These are stress ratings only and functional operation is not implied . Exposure to absolute maximum ratings for prolonged time periods may affect device reliability . All voltages are with respect to ground . Input Voltage Range............................-0.3V to 6V Operation Junction Temperature.....-40°C to 125 °C PWM Pin voltage............... -0.3V to (VIN+0.3V)/6V Storage Temperature.....................-65 °C to 150 °C Maximum Junction Temperature..................150°C Soldering Temperature....................... 300°C,5sec
Recommended Operating Conditions
Input Voltage Range.......................... 2.7V to 5.5V Operation Temperature Range.........-40 °C to 85 °C
Thermal Information
Parameter Thermal Resistance (Junction to Ambient) Thermal Resistance (Junction to Case) Symbol Package SOT23-8 θJA DFN SOT23-8 θJC DFN 20 102 ºC/W 130 Maximum 250 Unit
Electrical Characteristic
T A=25°C, V IN=3.6V, R SET=5.1k Ω, V LEDX=0.5V, unless otherwise noted.
PARAMETER Input Voltage
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Symbol V IN ILEDX ILED-MATCH VDROPOUT V SET ILEDX/ISET IQ ISHDN VHI V LO IEN
CONDITIONS
MIN Vf+V LED (Note)
TYP 3.6
MAX 5.5 40 ±5
UNITS V mA % V V
Output Current
VDD=5V
Current Matching Between Any Two Outputs Current Sink Dropout ISET PIN Voltage Output Current to Current Set Ratio Quiescent Supply Current Shutdown Supply Current EN Input Logic High EN Input Logic Low EN Pin Current
Rset=3kΩ,ILEDX=40mA 1.22 100 Rset=10MΩ,with no loads EN=logic low 1.4 65 0.1
0.25
80 1 0.4
μA μA V V μA μA
V(EN) = 1.5V V(EN) = 0V
0.1 0.1
1 1
Note: Vf: LED forward voltage; V LED: voltage of LEDx pins.
Power Analog Microelectronics , Inc
www.poweranalog.com 07/2008 Rev 1.1
4
4-Channel Programmable LED Current Sink
PAM2810
Typical Performance Characteristics
T A=25°C, V IN=3.6V, R SET=5.1k Ω, V LEDX=0.5V, unless otherwise noted.
LED Current VS LED Pin Voltage 45 40
LED Current (mA)
45 40 35 LED Curent VS Input Voltage
35 30 25 20 15 10 5 0 0 0.3 0.6 0.9 1.2 1.5 LED Pin Voltage(V)
R=12.7KΩ R=4.3KΩ R=6.2KΩ R=3.2KΩ
LED Curent(mA)
30 25 20 15 10 5 0 3 3.5 4 4.5 5 5.5 Input Voltage(V)
R=12.7KΩ R=4.3KΩ R=6.2KΩ R=3.2KΩ
VIset VS Input Voltage 1.2135 1.2125
LED Current VS Rset 50 45 40
LED Current(mA)
1.2115
Viset(V)
35 30 25 20 15 10 5 0
1.2105 1.2095 1.2085
www.DataSheet4U.com 1.2075
3
3.5
4
4.5
5
5.5
0
5
10 Rset(kΩ)
15
20
Input Voltage(V)
Efficiency VS Input Voltage 100 9.