4-Channel Programmable LED Current Sink
PAM2810
Features
n
n
n
n
n
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.
n
n
n
n
n
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
LED1 8
1
LED2 7
PAM2810
LED3 6
LED4
GND
5
ISET
R1
6.2
k
3
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
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
Power Analog Microelectronics
,
Inc
www.poweranalog.com
07/2008 Rev 1.1
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
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
θ
JA
DFN
SOT23-8
θ
JC
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
Output Current
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
Symbol
V
IN
I
LEDX
I
LED-MATCH
V
DROPOUT
V
SET
I
LEDX
/I
SET
I
Q
I
SHDN
V
HI
V
LO
I
EN
V(EN) = 1.5V
V(EN) = 0V
0.1
0.1
Rset=10MΩ,with no loads
EN=logic low
1.4
0.4
1
1
Rset=3kΩ,I
LEDX
=40mA
1.22
100
65
0.1
80
1
μA
μA
V
V
μA
μA
V
DD
=5V
CONDITIONS
MIN
Vf+V
LED
（Note）
TYP
3.6
MAX
5.5
40
±5
0.25
UNITS
V
mA
%
V
V
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
1.2075
3
3.5
4
4.5
5
5.5
Input Voltage(V)
0
5
10
Rset(kΩ)
15
20
Efficiency VS Input Voltage
100
90
80
Efficiency(%)
LED Current vs PWM Duty Cycle
30
25
LED Current (mA)
70
60
50
40
30
20
10
0
3
Rset=6.2k
20
15
10
5
0
3.25
3.5
3.75
4
4.25
4.5
0
20
40
60
80
100
Input Voltage(V)
PWM Duty Cycle (%)
Power Analog Microelectronics
,
Inc
www.poweranalog.com
07/2008 Rev 1.1
5
京公网安备 11010802033920号
EEWORLD
