Data Sheet No. PD94140
IRU3004
5-BIT PROGRAMMABLE SYNCHRONOUS BUCK
CONTROLLER IC WITH DUAL LDO CONTROLLER
DESCRIPTION
The IRU3004 controller IC is specifically designed to meet
Intel specifications for Pentium III™ microprocessor
applications as well as the next generation P6 family
processors. The IC provides a single chip controller IC
for the Vcore, GTL+ and clock supplies required for the
Pentium III applications. The IRU3004 features a pat-
ented topology, that in combination with a few external
components as shown in the typical application circuit,
will provide in excess of 20A of output current for an on-
board DC-DC converter while automatically providing the
right output voltage via the 5-bit internal DAC meeting
the latest VRM specification. The IRU3004 also features
loss-less current sensing by using the R
DS(on)
of the high
side power MOSFET as the sensing resistor and a Power
Good window comparator that switches its open collec-
tor output low when the output is outside of a
±10%
window. Other features of the device are: under-voltage
lockout for both 5V and 12V supplies, an external pro-
grammable soft-start function as well as programming
the oscillator frequency by using an external capacitor.
FEATURES
Meets latest VRM 8.4 specification for PentiumIII
Provides single chip solution for Vcore, GTL+ and
clock supply
On-Board DAC programs the output voltage from
1.3V to 3.5V. The IRU3004 remains on for VID code
of (11111)
Dual linear regulator controller on-board for 1.5V
GTL+ and 2.5V clock supplies
Loss-less Short Circuit Protection
Synchronous operation allows maximum efficiency
Patented architecture allows fixed frequency opera-
tion as well as 100% duty cycle during dynamic
load
Minimum Part Count, No External Compensation
Soft-Start Function
High current totem pole driver for direct driving of the
external power MOSFET
Power Good Function
APPLICATIONS
Pentium III & next generation processor DC to DC
converter application
Low Cost Pentium with AGP
TYPICAL APPLICATION
5V
L1
C5
C13
C3
R2
R1
Q1
L2
R16
C7
Q2
R4
R3
R12
R13
R17
C16
Note:
Pentium III is trademark of Intel Corp.
V
OUT
3
C10
3.3V
C4
C6
Q3
C11
V12
Ct
C1
SS
C2
D4
D3
D2
D1
D0
V
FB2
PGd
V5
CS+
HDrv
CS-
LDrv
Gnd
V
FB3
R11
Lin1
R7
V
OUT
1
12V
R18
IRU3004
V
FB1
Lin2
3.3V
C9
Q4
C15
R8
V
OUT
2
C12
R14
VID4
VID3
VID2
VID1
VID0
C8
R5
R9
C14
R15
Power Good
Figure 1 - Typical application of the IRU3004.
PACKAGE ORDER INFORMATION
T
A
(8C)
0 To 70
0 To 70
Rev. 1.7
07/16/02
DEVICE
IRU3004CW
IRU3004CF
PACKAGE
20-Pin Plastic SOIC (W)
20-Pin Plastic TSSOP (F)
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1
IRU3004
ABSOLUTE MAXIMUM RATINGS
V5 Supply Voltage ....................................................
V12 Supply Voltage ..................................................
Storage Temperature Range ......................................
Operating Junction Temperature Range .....................
10V
20V
-65°C To 150°C
0°C To 125°C
PACKAGE INFORMATION
20-PIN WIDE BODY PLASTIC SOIC (W)
TOP VIEW
Ct 1
Lin1 2
V
FB1
3
V
FB2
4
V5 5
PGd 6
CS- 7
CS+ 8
HDrv 9
Gnd 10
20 Lin2
19 D 0
18 D 1
17 D 2
16 D 3
15 D 4
14 V
FB3
13 SS
12 V12
11 LDrv
Ct 1
Lin1 2
V
FB1
3
V
FB2
4
V5 5
PGd 6
CS- 7
CS+ 8
HDrv 9
Gnd 10
20-PIN PLASTIC TSSOP (F)
TOP VIEW
20 Lin2
19 D 0
18 D 1
17 D 2
16 D 3
15 D 4
14 V
FB3
13 SS
12 V12
11 LDrv
u
JA
=858C/W
u
JA
=908C/W
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over V12=12V, V5=5V and T
A
=0 to 70°C. Typical values refer
to T
A
=25°C. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient
temperature.
PARAMETER
VID Section
DAC Output Voltage (Note 1)
DAC Output Line Regulation
DAC Output Temp Variation
VID Input LO
VID Input HI
VID Input Internal Pull-Up
Resistor to V5
Power Good Section
Under-Voltage lower trip point
Under-Voltage upper trip point
UV Hysteresis
Over-Voltage upper trip point
Over-Voltage lower trip point
OV Hysteresis
Power Good Output LO
Power Good Output HI
Soft-Start Section
Soft-Start Current
SYM
TEST CONDITION
MIN
0.98Vs
TYP
Vs
MAX
1.02Vs
0.1
0.5
0.4
UNITS
V
%
%
V
V
KV
2
27
V
OUT
Ramping Down
V
OUT
Ramping Up
V
OUT
Ramping Up
V
OUT
Ramping Down
R
L
=3mA
R
L
=5K Pull-Up to 5V
CS+=0V, CS-=5V
0.89Vs
0.015Vs
1.09Vs
0.015Vs
4.8
0.90Vs
0.92Vs
0.02Vs
1.10Vs
1.08Vs
0.02Vs
0.91Vs
0.025Vs
1.11Vs
0.025Vs
0.4
V
V
V
V
V
V
V
V
mA
10
2
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Rev. 1.7
07/16/02
IRU3004
PARAMETER
UVLO Section
UVLO Threshold-12V
UVLO Hysteresis-12V
UVLO Threshold-5V
UVLO Hysteresis-5V
Error Comparator Section
Input Bias Current
Input Offset Voltage
Delay to Output
Current Limit Section
CS Threshold Set Current
CS Comp Offset Voltage
Hiccup Duty Cycle
Supply Current
Operating Supply Current
SYM
TEST CONDITION
Supply Ramping Up
Supply Ramping Up
MIN
9.2
0.3
4.1
0.2
TYP
10
0.4
4.3
0.3
MAX
10.8
0.5
4.5
0.4
2
+2
100
200
240
+5
2
UNITS
V
V
V
V
mA
mV
ns
mA
mV
%
-2
V
DIFF
=10mV
160
-5
Css=0.1mF
C
L
=3000pF:
V5
V12
C
L
=3000pF
C
L
=3000pF
C
L
=3000pF
Ct=150pF
20
14
70
70
200
220
V5
1.455
1.500
50
1.545
2
100
130
300
260
0.2
mA
Output Drivers Section
Rise Time
Fall Time
Dead Band Time
Oscillator Section
Osc Frequency
Osc Valley
Osc Peak
LDO Controller Section
V
FB1
& V
FB2
Input Bias Current
Lin1 or Lin2 Drive Current
100
160
ns
ns
ns
KHz
V
V
V
mA
mA
Note 1:
Vs refers to the set point voltage given in Table 1.
D4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D3
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
D2
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
D1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
D0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
Vs
1.30
1.35
1.40
1.45
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
1.95
2.00
2.05
D4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
D3
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
D2
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
D1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
D0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
Vs
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
Table 1 - Set point voltage vs. VID codes.
Rev. 1.7
07/16/02
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IRU3004
PIN DESCRIPTIONS
PIN#
1
2
3
4
5
6
PIN SYMBOL
Ct
Lin1
V
FB1
V
FB2
V5
PGd
PIN DESCRIPTION
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 R
DS
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.
7
8
CS-
CS+
9
10
HDrv
Gnd
11
12
LDrv
V12
13
SS
14
15
16
17
18
19
20
V
FB3
D4
D3
D2
D1
D0
Lin2
4
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Rev. 1.7
07/16/02
IRU3004
BLOCK DIAGRAM
14
Enable
V12
Vset
Enable
9
V
FB3
HDrv
V12
V5
12
UVLO
5
+
Vset
PWM
Control
V12
11
D0
D1
D2
D3
D4
19
18
17
16
15
Enable
Slope
Comp
LDrv
CS-
CS+
5Bit
DAC,
Ctrl
Logic
Osc
7
Over
Current
8
Soft
Start &
Fault
Logic
200uA
Enable
1
Ct
SS
V
FB2 4
13
Lin2
20
1.1Vset
6
PGd
1.5V
Lin1
V
FB1
2
0.9Vset
3
10
Gnd
Figure 2 - Simplified block diagram of the IRU3004.
Rev. 1.7
07/16/02
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