4
Rev. 1.4
08/20/02
IRU3013
www.irf.com
PIN DESCRIPTIONS
This pin programs the oscillator frequency in the range of 50 KHz to 500KHz by means of
an external capacitor connected from this pin to the ground.
Controls the gate of an external MOSFET for the AGTL+ linear regulator or 1.8V supply.
This pin provides the feedback for the linear regulator that its output drive is Lin1 pin.
This pin provides the feedback for the linear regulator that its output drive is Lin2 pin.
5V supply voltage.
This pin provides an over voltage flag when the feedback pin VFB 3 voltage exceeds 17%(Typi-
cal) of the set point for the Vcore output.
This pin is an open collector output that switches LO when the output of the converter is
not within ±10% (typ) of the nominal output voltage. When PGd pin switches LO the
output saturation voltage is less than 0.4V at 3mA.
This pin is connected to the Source of the power MOSFET for the Core supply and it is
the negative input for the internal current sensing circuitry.
This pin is connected to the Drain of the power MOSFET of the Core supply. It provides the
positive sensing input for the internal current sensing circuitry. An external resistor pro-
grams the CS threshold depending on the RDS of the power MOSFET. An external capaci-
tor is placed in parallel with the programming resistor to provide high frequency noise
filtering.
Output driver for the high side power MOSFET.
This is the power ground pin and must be connected directly to the gnd plane close to the
source of the synchronous MOSFET. A high frequency capacitor (typically 1mF) must be
connected from V12 pin to this pin for noise free operation.
This pin must be connected directly to the ground plane. A high frequency capacitor (0.1
to 1mF) must be connected from V5 and V12 pins to this pin for noise free operation.
Output driver for the power MOSFET, which is used as a synchronous switched rectifier.
This pin is connected to the 12V supply and serves as the power Vcc pin for the output
drivers. A high frequency capacitor (0.1 to 1mF) must be connected directly from this pin
to Gnd pin in order to supply large instantaneous current pulses to the power MOSFET
during the transitions.
This pin provides the feedback for the linear regulator that its output drive is Lin4 pin.
This pin controls the gate of an external MOSFET for either the AGP Bus linear regulator
or can be used as Power good detector for 1.2V AGTL+ bus.
This pin provides the soft-start for the switching regulator. An internal current source
charges an external capacitor that is connected from this pin to the ground which ramps
up the outputs of the switching regulator, preventing the outputs from overshooting as well
as limiting the inrush current. The second function of the Soft-Start cap is to provide long
off time (HICCUP) for the synchronous MOSFET during current limiting.
This pin is connected directly to the output of the Core supply to provide feedback to the
Error comparator.
This pin programs the output voltage in 25mV steps based on the VID table. 40K internal
pull-up to Vcc.
MSB input to the DAC that programs the output voltage. This pin can be pulled-up exter-
nally by a 10K resistor to either 3.3V or 5V supply. 40K internal pull-up to Vcc.
Input to the DAC that programs the output voltage. This pin can be pulled-up externally by
a 10K resistor to either 3.3V or 5V supply. 40K internal pull-up to Vcc.
Input to the DAC that programs the output voltage. This pin can be pulled-up externally by
a 10KV resistor to either 3.3V or 5V supply. 40K internal pull-up to Vcc.
LSB input to the DAC that programs the output voltage. This pin can be pulled-up exter-
nally by a 10K resistor to either 3.3V or 5V supply. 40K internal pull-up to Vcc.
Controls the gate of an external MOSFET for the AGTL+ linear regulator or 1.8V supply.
PIN# PIN SYMBOL PIN DESCRIPTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Ct
Lin1
VFB1
VFB2
V5
OVP
PGd
CS-
CS+
HDrv
PGnd
Gnd
LDrv
V12
VFB4
Lin4
SS
VFB3
D25
D3
D2
D1
D0
Lin2
