4
FN7317.2
February 4, 2005
Pin Descriptions I = Input, O = Output, S = Supply
PIN NUMBER PIN NAME PIN TYPE PIN FUNCTION
1 SS I Soft-Start input: a capacitor determines the current limit ramp time.
2 FBB I Voltage feedback input determines the value of V
BOOST
.
3 EN I Starts internal power sequencing of V
BOOST
, V
OFF
, V
COM
and V
ON
outputs
(See Applications Information) ; active HIGH input.
4 VDDB P Positive supply for V
BOOST
DC/DC controller.
5 LX1 O Boost inductor saturating MOSFET #1.
6 LX2 O Boost inductor saturating MOSFET #2.
7 VSSN* P Ground return for V
OFF
regulator.
8 DRVN O Pump capacitor driver for V
OFF
regulator.
9 VDDN P Positive supply for V
OFF
regulator.
10 FBN I Voltage feedback input determines the value of V
OFF
.
11 DP I An external capacitor increases V
ON
power up delay time.
12 INC I V
COM
Buffer input.
13 VDDC P Positive supply for V
COM
Buffer.
14 VCOM O V
COM
Buffer output.
15 VSSC* P Ground return for V
COM
Buffer.
16 FBP I Voltage feedback input determines the value of V
ON
.
17 VDDP P Positive supply for V
ON
regulator.
18 DRVP O Pump capacitor driver for V
ON
regulator.
19 VSSP* P Ground return for V
ON
regulator.
20 PGND* P Ground return for MOSFET #1.
21 PGND* P Ground return for MOSFET #2.
22 VREF O Voltage reference for V
OFF
feedback .
23 ROSC I An external resistor sets the DC/DC switching frequency.
24 VSSB* P Ground return for V
BOOST
DC/DC controller.
NOTE: *VSSB, VSSC, VSSN, VSSP, and PGND (2) are shorted internally to the device substrate.
EL7584
