2
FIGURE 2. SP6651A
1.5V OUTPUT
EVALUATION BOARD SCHEMATIC
USING THE EVALUATION BOARD
1) Powering up the SP6651A Circuit & Programming the UVLO threshold
The SP6651A Evaluation Board
can be powered from a single Li-Ion battery or a +2.7 to
+6.5V power supply. Connect with short leads directly to the “Vin” and “Gnd” posts.
Note the SP6651A 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
0
0
Shutdown. All internal circuitry is disabled and the power switches are opened.
0
1
Device enabled, falling UVLO threshold = 2.70V
1
0
Device enabled, falling UVLO threshold = 2.85V
1
1
Device enabled, falling UVLO threshold = 3.00V
2) VOUT PROGRAMMING
The SP6651A requires 2 feedback resistors to control the output voltage. Connect the
appropriate resistors RF and RI (Table 2) from pin 6 SP6651A 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
3
Vout 1.5V 800mA
Vin 2.7 - 6.5VDC
3
1
RVIN
10.0
D0
RI
261K
SP6651A
U1
1
2
3
4
5
6
7
8
9
10
PVin
Vin
BLON
D1
D0
FB
Vout
GND
PGND
LX
J2
J1
COUT
22uF
CF
22pF
L1
10uH
CVIN
1.0uF
2
RF
226K
2
BLON
CIN
22uF
1
D1