Diodes PAM2841 User Manual

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Description

The PAM2841 is a white LED driver, capable of driving 10 or more

WLEDs in series (depending on forward voltage of the LEDs) with a

range of input voltages from 2.7V to 5.5V.

The PAM2841 features over current protection, over voltage

protection, under voltage lockout and over temperature protection,

which prevent the device from damage.

LED dimming can be done by four methods as described in the

Application Information hereinafter.

Features

 Capable of Driving 10 or More WLEDs

 Chip Enable with Soft-Start

 Analog and PWM Dimming

 Peak Efficiency up to 90%

 Low Quiescent Current

 Fixed Frequency of 1MHz

 Over Current Protection

 Over Voltage Protection

 Thermal Protection

 UVLO

 Tiny Pb-Free Packages (RoHS Compliant):

MSOP-8 and DFN 2X2

Applications

 WLED Driver System

Typical Applications Circuit

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PAM2841

1.5A SW CURRENT, 40V PRECISION WLED DRIVER

Pin Assignments

PAM2841

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Typical Applications Circuit (cont.)

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PAM2841

Pin Descriptions

Number

1 PGND 2 VIN 3 ENA 4 Comp 5 GND 6 FB 7 OVP 8 SW

Name

Power Ground

Input Voltage

Chip Enable, Active High

Compensation Node

Chip Ground

Feedback

Over Voltage

Drain of Main Switch

Functional Block Diagram

Function

PAM2841

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PAM2841

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

Supply Voltage 6.0

I/O Pin Voltage Range

Maximum SW Pin Voltage 40

Storage Temperature -65 to +170

Maximum Junction Temperature 170

Soldering Temperature 300, 5sec

Recommended Operating Conditions (@T

Parameter Rating Unit

Supply Voltage Range 2.8 to 5.5 V

Operation Temperature Range -40 to +85

Junction Temperature Range -40 to +150

= +25°C, unless otherwise specified.)

A

GND -0.3 to V

+0.3

DD

= +25°C, unless otherwise specified.)

A

V

°C

Thermal Information

Parameter Package Symbol Max Unit

Thermal Resistance (Junction to Ambient)

Thermal Resistance (Junction to Case)

PAM2841

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MSOP-8

DFN2x2-8 80

MSOP-8

DFN2x2-8 30

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180

75

°C/W

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PAM2841

Electrical Characteristics (@T

Parameter Symbol Test Conditions Min Typ Max Units

Supply Voltae Range

Quiescent Current

Shutdown Current

Output Current

Output Voltage Range

Feedback Voltage

SW On-Resistance

SW Current Limit

SW Frequency

Maximum Duty Cycle DC 95 %

Over Voltage Protection Threshold OVP Open Load 1.2 V

Enable Threshold Voltage

Under Voltage Lockout UVLO

UVLO Hysterisis

Over Temperature Shutdown OTS 150 °C

Over Temperature Hysterisis OTH 30 °C

PAM2841

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= +25°C, VEN = V

A

V

I

SD

DD

No Switching

Q

V

ENA

R3 = 5.1Ω 40

I

R3 = 6.8Ω 30

O

R3 = 10Ω 20 R3 = 20Ω 10

O

V

FB

EL

ENA

I

SW

Switch On 1.5 A

0.7 1.0 1.3 MHz

Chip Shutdown 0.4

Chip On 1.2

V

IN

0.2 V

TH

V

R

DS(ON)

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V

VEH

V

LIM

SW

=5.0V, 10 LEDs, unless otherwise specified.)

DD

= low

= high

= 100mA

falling

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2.7 5.5 V

200 300 µA

1 µA

mA

x

V

IN

1.1

40 V

194 200 206 mV

0.35 0.5 Ω

V

2.0 2.2 2.4 V

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Typical Performance Characteristics (@T

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= +25°C, VDD = 5V, unless otherwise specified.)

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PAM2841

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