IRU3021MCWTR International Rectifier, IRU3021MCWTR Datasheet - Page 5

• Manufacturer Part Number: IRU3021MCWTR
• Description: IC CTRL/REG SYNC BUCK 28-SOIC
• Manufacturer: International Rectifier

Specifications of IRU3021MCWTR

• Applications: Controller, Intel Processor
• Voltage - Input: 5V, 12V
• Number Of Outputs: 4
• Voltage - Output: 1.3 ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

PIN#
Rev. 1.5
07/17/02
10
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
11
9
PIN SYMBOL
Fault / Rt
OCSet
Select
Phase
UGate
Drive4
Drive3
LGate
V
V
V
V
PGnd
Gnd
V12
SD
SS
NC
V5
SEN
SEN
SEN
Fb
SEN
2
4
3
1
This pin provides shutdown for all the regulators. A TTL compatible, logic level high applied
to this pin disables all the outputs and discharges the soft-start capacitor. The SD signal
turns off the synchronous MOSFET allowing body diode to conduct and discharge the
output capacitor.
This pin provides the feedback for the AGP linear regulator. The Select pin when con-
nected to the "Type Detect" pin of the AGP slot automatically selects the right voltage for
the AGP V
This pin provides automatic voltage selection for the AGP switching regulator. When it is
pulled LO, the voltage is 1.5V and when left open or pulled to HI, the voltage is 3.3V.
This pin provides the soft-start for all the regulators. An internal current source charges an
external capacitor that is connected from this pin to ground which ramps up the outputs of
the regulators, preventing the outputs from overshooting as well as limiting the input cur-
rent. The second function of the Soft-Start cap is to provide long off time (HICCUP) for the
synchronous MOSFET during current limiting.
This pin has dual function. It acts as an output of the over-voltage protection circuitry or it
can be used to program the frequency using an external resistor. When used as a fault
detector, if any of the switcher outputs exceed the OVP trip point, the Fault pin switches
to 12V and the soft-start cap is discharged. If the Fault pin is to be connected to any
external circuitry, it needs to be buffered.
This pin provides the feedback for the linear regulator that its output drive is Drive4.
This pin controls the gate of an external MOSFET for the 1.8V chip set linear regulator.
This pin is not connected internally.
This pin serves as the ground pin and must be connected directly to the ground plane.
This pin controls the gate of an external transistor for the 1.5V GTL+ linear regulator.
This pin provides the feedback for the linear regulator that its output drive is Drive3.
5V supply voltage. A high frequency capacitor (0.1 to 1mF) must be placed close to this
pin and connected from this pin to the ground plane for noise free operation.
This pin provides the feedback for the synchronous switching regulator. Typically this pin
can be connected directly to the output of the switching regulator. However, a resistor
divider is recommended to be connected from this pin to V
output voltage for any drop in the output voltage that is caused by the trace resistance.
The value of the resistor connected from V
This pin is internally connected to the under-voltage and over-voltage comparators sens-
ing the Vcore status. It must be connected directly to the Vcore supply.
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 resistor pro-
grams the current sense threshold depending on the R
external capacitor is placed in parallel with the programming resistor to provide high fre-
quency noise filtering.
This pin serves as the Power ground pin and must be connected directly to the ground
plane close to the source of the synchronous MOSFET. A high frequency capacitor (typi-
cally 1mF) must be connected from V12 pin to this pin for noise free operation.
Output driver for the synchronous power MOSFET for the Core supply.
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.
Output driver for the high side power MOSFET for the Core supply.
This pin is connected to the 12V supply and serves as the power Vcc pin for the output
drivers. A high frequency capacitor (typically 1mF) must be placed close to this pin and
PGnd pin and be connected directly from this pin to the ground plane for the noise free
operation.
PIN DESCRIPTION
DDQ
.
www.irf.com
OUT
1 to Fb1 must be less than 1000V.
DS
OUT
of the power MOSFET. An
1 and ground to adjust the
IRU3021M
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