RT9246
Functional Pin Description
VID4 (Pin 1), VID3 (Pin 2), VID2 (Pin 3), VID1 (Pin 4),
VID0 (Pin 5)
DAC voltage
identification inputs for K8. These pins are
internally pulled to 2.4V if left open.
VOSS (Pin 14)
SS2 (Pin 6)
DAC O/P ramping speed control for K8. Connect this pin
to GND with a capacitor to set the rising/falling time at
VID jump.
SGND (Pin 7)
V
CORE
differential sense negative input.
FB (Pin 8)
Inverting input of the internal error amplifier.
COMP (Pin 9)
Output of the error amplifier and input of the PWM
comparator.
PGOOD (Pin 10)
Power good open-drain output.
DVD (Pin 11)
Programmable power UVLO
detection or converter enable
input.
SS (Pin 12)
Connect this SS pin to GND with a capacitor to set the
soft-start time interval.
450
400
350
300
RT (Pin 13)
Switching frequency setting. Connect this pin to GND with
a resistor to set the frequency.
V
CORE
initial value offset. Connect this pin to GND with a
resistor to set the offset value.
IMAX (Pin 15)
Over-Current protection set.
VSEN (Pin 16)
V
CORE
differential sense positive input.
VDIF (Pin 17)
V
CORE
differential sense output.
ADJ (Pin 18)
Current sense output for active droop adjust. Connect a
resistor from this pin to GND to set the load droop.
GND (Pin 19)
IC ground.
ISN23 (Pin 20)
R
DS(ON)
current sense inputs from converter 2
nd
& 3
rd
phase
channel sense components' GND node.
ISP1 (Pin 23), ISP2 (Pin 22), ISP3 (Pin 21)
R
DS(ON)
current sense inputs for individual converter
channels. Tie this pin to the component's sense node.
ISN1 (Pin 24)
R
DS(ON)
current sense inputs from converter 1
st
channel
sense component's GND node.
Frequency vs. R
RT
f
OSC
(kHz)
250
200
150
100
50
0
0
10
20
30
40
50
60
70
PWM1 (Pin 27), PWM2 (Pin 26), PWM3 (Pin 25)
PWM outputs for each driven channel. Connect these pins
to the PWM input of the MOSFET driver. For systems
which use 2 channels, connect PWM3 high.
VCC (Pin 28)
IC power supply. Connect this pin to a 5V supply.
R
RT
(k
Ω)
DS9246-06 March 2007
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
