Package Pin Description
PACKAGE PIN #
PIN SYMBOL
FUNCTION
16L SO Narrow & PDIP
1,2,3,4
VID0 – VID3
Voltage ID DAC input pins. These pins are internally pulled up to 5V
providing logic ones if left open. The DAC range is 2.14V to 3.54V with
100mV increments. VID0 - VID3 select the desired DAC output voltage.
Leaving all 4 DAC input pins open results in a DAC output voltage of
1.244V, allowing for adjustable output voltage, using a traditional resis-
tor divider.
5
SS
Soft Start Pin. A capacitor from this pin to LGnd in conjunction with
internal 60µA current source provides soft start function for the con-
troller. This pin disables fault detect function during Soft Start. When a
fault is detected, the soft start capacitor is slowly discharged by internal
2µA current source setting the time out before trying to restart the IC.
Charge/discharge current ratio of 30 sets the duty cycle for the IC when
the regulator output is shorted.
6, 12
7
NC
COFF
No connection.
A capacitor from this pin to ground sets the time duration for the on
board one shot, which is used for the constant off time architecture.
8
VFFB
Fast feedback connection to the PWM comparator. This pin is connected
to the regulator output. The inner feedback loop terminates on time.
9
10
11
VCC2
VGATE
PGnd
Boosted power for the gate driver.
MOSFET driver pin capable of 1.5A peak switching current.
High current ground for the IC. The MOSFET driver is referenced to this
pin. Input capacitor ground and the anode of the Schottky diode should
be tied to this pin.
13
14
15
VCC1
LGnd
COMP
Input power for the IC.
Signal ground for the IC. All control circuits are referenced to this pin.
Error amplifier compensation pin. A capacitor to ground should be pro-
vided externally to compensate the amplifier.
16
VFB
Error amplifier DC feedback input. This is the master voltage feedback
which sets the output voltage. This pin can be connected directly to the
output or a remote sense trace.
4
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
