Rev 10/17/05

SP6655 Evaluation Board Manual

2

1) Powering up the SP6656 Circuit

The SP6656 Evaluation Board can be powered from a single Li-Ion battery or a +2.7 to

+5.0V power supply. Connect with short leads directly to the “Vin” and “Gnd” posts.

Note the SP6656 will remain in “shutdown” until the EN Jumper J1 is applied to the Vin

or position 1 to 2.

2) VOUT PROGRAMMING

The SP6656 has a dynamically programmable output voltage using the OVSI and

OVSO pins. This requires 2 feedback resistors to control the output voltage as well as

an Rs resistor for the dynamically programmed output voltage. Connect the appropriate

resistors RF and RI (Table 1) from pin 6 SP6656 FB to Vout and to the GND.

For Vout Low, select OVSI = L and use the formula below to set the output voltage:

RI

Vout

RF

•













−

=

1

8

.

0

For Vout High, select OVSI = L, and the RS resistor will be switched in to change the

output voltage from the previously set voltage to a larger output voltage, determined by

the following equation:

RA

Vout

RF

•













−

=

1

8

.

0

where

RS

RI

RS

RI

RA

+

=

*

Table 1. SP6656EB BILL OF MATERIALS

Component

Vo = 1.8V

L1

10uH, Murata LQH32CN100K11, 0.3ohm, 0.45A, 1210

CIN

10uF, TDK C2012X5R0J106M, 0.005ohm, 6.3V, X5R, 0805

COUT

10uF, TDK C2012X5R0J106M, 0.005ohm, 6.3V, X5R, 0805

RVIN

10 Ohm 5%, 0603

CVIN

1uF, TDK C1608X5R0J105M, 0.03ohm, .3V, X5R, 0603

RI

200k 1%, 0603

RF

249k 1%, 0603

RF

200k 1%, 0603

CF

22pF ceramic, 0603