Diodes PAM2803 User Manual
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Description
The PAM2803 is a set-up DC-DC converter that delivers a regulated
output current. The device switches at a 1.0MHz constant frequency,
allowing for the use of small value external inductor and ceramic
capacitors.
The PAM2803 is targeted to be used for driving loads up to 1A from a
two-cell alkaline battery. The LED current can be programmed by the
external current sense resistor, R
pin (FB) and ground. A low 95mV feedback voltage reduces the
power loss in the Rs for better efficiency. With its internal 2A, 100m
NMOS switch, the device can provide high efficiency even at heavy
load. During the shutdown mode, the feedback resistor R
load are completely disconnected and the current consumption is
reduced to less than 1µA.
The PAM2803 is available in the 6-lead TSOT26 package.
, connected between the feedback
S
and the
S
Features
LED Power Efficiency: up to 90%
Current Accuracy: 5%(V
Low Start-Up Voltage: 0.9V (I
Low Hold Voltage: 0.75 (I
1MHz Switching Frequency
Uses Small, Low Profile External Components
Low R
Over Temperature Protection
Low Profile TSOT26 Package
Pb-Free Package
: 100m (typ)
DS(ON)
= 3.6V to 1.8V @VF = 3.7V)
IN
= 270mA)
LED
= 200mA)
LED
Typical Applications Circuit
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3W HIGH POWER WHITE LED DRIVER
Pin Assignments
Top View
TSOT26
Applications
White LED Torch (Flashlight)
White LED Camera Flash
DSC(Digital Still Camera)Flash
Cellular Camera Phone Flash
PDA Camera Flash
Camcorder Torch(Flashlight) Lamp
PAM2803
= 750mA, RS = 0.127Ω
I
LED
PAM2803
Document number: DSxxxxx Rev. 1 - 1
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Pin Description
Pin
Number
1
2
3
4
5 VOUT Output
6 VIN Input
Pin
Name
SW Switch
GND Ground
FB Feedback
SHDN Shut Down
Block Diagram
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PAM2803
Function
Absolute Maximum Ratings (@T
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.
Parameter Rating Unit
Input Pin Voltage -0.3 to +6
SW Pin Voltage -0.3 to +6
SHDN, FB Pin Voltage -0.3 to +6
Operating Temperature Range -40 to +85
Storage Temperature Range -65 to +125
Lead Temperature (Soldering, 5 sec) 300
Recommended Operating Conditions (@T
Parameter Rating Unit
Junction Temperature -40 to +125
Ambient Temperature -40 to +85
PAM2803
Document number: DSxxxxx Rev. 1 - 1
= +25°C, unless otherwise specified.)
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V
°C
= +25°C, unless otherwise specified.)
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°C
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PAM2803
Thermal Information
Parameter Symbol Package Max Unit
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
Internal Power Dissipation
JC
JA
P
D
TSOT26 130
TSOT26 250
°C/W
TSOT26 400 mW
Electrical Characteristics
(@TA = +25°C, VIN = 2.4V, I
Parameter Symbol Test Conditions Min Typ Max Units
Input Voltage Range
Feedback Voltage
Start-Up Voltage
Hold Voltage
Oscillator Frequency
SHDN Input High
SHDN Input Low
Over Temperature Shutdown OTS 150 °C
Over Temperature Hysteresis OTH 15 °C
Maximum Output Current Range
Quiescent Current
Shutdown Current
Switch On Resistance
Current Limit
Efficiency
Note: 1. VF – LED forward voltage.
PAM2803
Document number: DSxxxxx Rev. 1 - 1
= 750mA, V
LED
= VIN, L = 2.2µH, CIN = 10µF, CO = 10µF, unless otherwise specified.)
SHDN
V
IN
V
FB
V
VIN: 0V – 3V, I
START
VIN: 3V – 0V, I
V
HOLD
F
OSC
VIN = 1.8V
V
SH
V
VIN = 1.8V
SL
I
O(MAX)
I
Q
I
SD
VO = 3.4V
R
DS(ON)
VO = 3.4V
I
LIM
0.9
-0.2
V
F
(Note 1)
V
90 95 100 mV
= 370mA
LED
: 750mA – 200mA
LED
0.9 V
0.75 V
0.85 1.0 1.15 MHz
1.0 V
0.4 V
750 mA
= 0mA, VO = 3.4V,
I
LED
Device Switching @ 1MHz
1 3 mA
Shutdown Mode 1 µA
0.1
2 A
= 750mA
I
LED
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90 %
July 2013
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