USING THE EVALUATION BOARD

1) Powering up the SP6655 Circuit & Programming the UVLO threshold

The SP6655 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 SP6655 will remain in “shutdown” until D0 or D1 of the Jumpers J1 or J2 are

applied to the Vin or position 1 to 2. See Table 1 for UVLO threshold programming and

D1 and D0 pin definition.

Table 1. Operating Mode Definition

D1

D0

Definition

00

Shutdown. All internal circuitry is disabled and the power switches are opened.

01

Device enabled, falling UVLO threshold = 2.70V

10

Device enabled, falling UVLO threshold = 2.85V

11

Device enabled, falling UVLO threshold = 3.00V

2) VOUT PROGRAMMING

The SP6655 requires 2 feedback resistors to control the output voltage. Connect the

appropriate resistors RF and RI (Table 2) from pin 6 SP6655 FB to Vout and to the

GND.

For Vout different from that shown in the Table 2, use equation:

RI

Vout

RF

•













−

=

1

8

.

0

Table 2. SP6655UEB BILL OF MATERIALS

Component

Vo = 1.8V

L1

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

CIN

22uF, TDK C2012X5R0J106M, 0.005ohm, 6.3V, X5R, 0805

COUT

22uF, 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

CF

22pF ceramic, 0603

U1

SP6655ER, 10 pin DFN