4
Rev. 1.7
07/16/02
IRU3004
www.irf.com
PIN DESCRIPTIONS
This pin programs the oscillator frequency in the range of 50KHz to 500KHz with an
external capacitor connected from this pin to the ground.
This pin controls the gate of an external transistor for either the GTL+ linear regulator or
Clock 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 is an open collector output that switches LO when the output of the converter is
not within ±10% (typical) of the nominal output voltage. When Power Good pin switches
LO the sat 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
provides the negative sensing for the internal current sensing circuitry.
This pin is connected to the Drain of the power MOSFET of the Core supply and it
provides the positive sensing for the internal current sensing circuitry. An external resis-
tor programs the CS threshold depending on the RDS of the power MOSFET. An external
capacitor is placed in parallel with the programming resistor to provide high frequency
noise filtering.
Output driver for the high-side power MOSFET.
This pin serves as the ground pin and 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 synchronous power MOSFET.
This pin is connected to the 12 V 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 ground pin in order to supply the peak current to the power MOSFET duringthe transi-
tions.
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 input 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 selects a range of output voltages for the DAC. When in the LOW state the
range is 1.3V to 2.05V. For VID codes of all "1" the IRU3004 keeps all the outputs on.
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.
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.
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.
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.
This pin controls the gate of an external transistor for either the GTL+ linear regulator or
Clock 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
Ct
Lin1
VFB1
VFB2
V5
PGd
CS-
CS+
HDrv
Gnd
LDrv
V12
SS
VFB3
D4
D3
D2
D1
D0
Lin2
