Rev 5/17/05

SP7648 Evaluation Board Manual

Copyright 2005 Sipex Corporation

DESCRIPTION

The SP7648 Evaluation Board is designed to help the user evaluate the performance of the

SP7648 for use as a single/dual cell Alkaline or single cell Li-Ion to drive 1W LED. The output of

the SP7648 is preset to +5V or can be adjusted from +2V to +5V by manipulating two external

resistors. The evaluation board is a completely assembled and tested surface mount board

which provides easy probe access points to all SP7648 Inputs and Outputs so that the user can

quickly connect and measure electrical characteristics and waveforms.

SP7648 EVALUATION BOARD SCHEMATIC

Mode Out (TP)

R6 1K

Vout

Vref

D1

Shorted

Important:

0.1uF Ceramic Cap at Vout Pin

needed for stable regulation

Flash: Iout = 0.3V/((R2//R4+Q1 RDSon)//R1)

Torch: Iout = 0.8V/R1

WURTH(744042004)

Q1

MOSFET N

Vin

Si1400DL

SC-70

0805

0805

RLIM1

OPEN

0603

R4

open

R3

open

SW1

ON / OFF

1

2

R5

1M

J3 FLASH

1

2

3

R2

0.33 Ohm

Flash: FLASH = H

Torch: FLASH = L

C2

10uF

SP7648

VBATT

1

FLASH

2

RLIM

4

SHDN

5

FB

6

GND

7

PGND

8

NC

3

LX

9

VOUT

10

D2

1W LED

C1

10uF

C3

470pF

R1

4.02 Ohm

Rc

0.33 Ohm

L1 4.7uH

RLIM

1K

C4

0.1uF

3.0-4.2V

0603

Easy Evaluation for the

SP7648 Single or Dual Cell

Alkaline to 2V to 5V Output

Provides 700mA output at

3.6V output for Li-Ion Input

High Efficiency: 94%

µSOIC Package & SMT

components for small, low

profile Power Supply

SP7648

Evaluation Board Manual