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
RSRI
RA
+
=
*
Table 1. SP6656EB BILL OF MATERIALS
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
