Diodes PAM2805 User Manual

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3-MODES/ 3W WLED DRIVER WITH 1 OR 2 CELL BATTERY

Description

The PAM2805 is a step-up DC-DC WLED driver with 3 modes cycling function (100% brightness,25% brightness and 8.5Hz blinking).

The unique 3 modes cycling function can eliminate the needs of extra functional MCU or IC.

The PAM2805 can deliver up to 750mA output current by setting an external resistor.

The PAM2805 switches at a 1.0MHz constant frequency, allowing for the use of small value external inductor and ceramic capacitors.

A low 95mV feedback voltage reduces the power loss in the R better efficiency. With its internal 2A, 100m device can provide high efficiency even at heavy load.

The PAM2805 is available in TSOT26 package.

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Features

Diodes Incorporated

Pin Assignments

Applications

 White LED Torch (Flashlight)

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Top View

TSOT26

PAM2805

 3 Modes Cycling Function:

Power Off

<5S

Bright Dimming Blinking

 Reset to Bright Mode if Power Off time More Than 5S  Adjustable Output Current: Up to 750mA  8.5Hz Blinking Mode  Low Start-Up Voltage: 0.9V(typ)  Low SW on Resistance: 100m  Over Temperature Protection  Over Voltage Protection  TSOT26 Package  Pb-Free Package

Power Off

<5S

Power Off

<5S

Typical Applications Circuit

PAM2805

Document number: DSxxxxx Rev. 1 - 0

ILED + 95mV/R

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Pin Description

Number

1 2 3 4

5 VOUT Output Voltage 6 SW Connected to an internal NMOS switch

Name

VIN Input Voltage

GND Power Ground

BLK Connect A 1µF CAP for blinking

FB Feedback

Block Diagram

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Diodes Incorporated

PAM2805

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

Supply Voltage 6 Output Voltage 6 Storage Temperature Range -65 to +150 Lead Temperature (Soldering, 5 sec) 300

Recommended Operating Conditions (@T

Parameter Rating Unit

Operation Temperature Range -40 to +85 Junction Temperature Range -40 to +125

PAM2805

Document number: DSxxxxx Rev. 1 - 0

= +25°C, unless otherwise specified.)

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V

°C

= +25°C, unless otherwise specified.)

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PAM2805

Thermal Information

Parameter Symbol Package Max Unit

Thermal Resistance (Junction to Case) Thermal Resistance (Junction to Ambient)



JC



JA

Internal Power Dissipation @ TA = 25°C PD

TSOT26 130 TSOT26 250

°C/W

TSOT26 400 mW

Electrical Characteristics

(@TA = +25°C, L = 2.2µH, CIN = 10µF, C

Parameter Symbol Test Conditions Min Typ Max Units

Input Voltage Range

Feedback Voltage

Start-Up Voltage Hold Voltage Oscillator Frequency Over Temperature Shutdown OTS 150 °C

Over Temperature Hysteresis OTH 30 °C Maximum Output Current Range

Quiescent Current Switch On Resistance

Current Limit Over Voltage Protection (VOUT) Blinking Frequency

Note: 1. VF ---LED forward voltage

PAM2805

Document number: DSxxxxx Rev. 1 - 0

= 10µF, C

OUT

V

IN

V

FB

VIN: 0V 3V, I

V

START

VIN: 3V  0V, I

V

HOLD

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OSC

I

VIN = 2.4V

O(MAX)

I

Q

VO = 3.4V

R

DS(ON)

VO = 3.4V

I

LIM

V

OVP

F

C

BLK

= 1µF, V

BLK

= 3.4V unless otherwise specified.)

F

0.9

-0.2

V

F

(Note 1)

V

90 95 100 mV

= 200mA

LED

: 750mA  100mA

LED

0.9 V

0.7 V

0.85 1.0 1.15 MHz

750 mA

= 0mA, VO = 3.4V, Device Switching

I

LED

at 1MHz

1 3 mA

0.1 

2 A

4.5 V

BLK

= 1µF

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8.5 10 Hz

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