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FN7298 Rev 1.00 Page 1 of 19
October 25, 2004
FN7298
Rev 1.00
October 25, 2004
EL7571
Programmable PWM Controller
DATASHEET
The EL7571 is a flexible, high efficiency, current mode,
PWM step down controller. It incorporates five bit DAC
adjustable output voltage control which conforms to the Intel
Voltage Regulation Module (VRM) Specification for
Pentium® II and Pentium® Pro class processors. The
controller employs synchronous rectification to deliver
efficiencies greater than 90% over a wide range of supply
voltages and load conditions. The on-board oscillator
frequency is externally adjustable, or may be slaved to a
system clock, allowing optimization of RFI performance in
critical applications. In single supply operation, the high side
FET driver supports boot-strapped operation. For maximum
flexibility, system operation is possible from either a 5V rail,
a single 12V rail, or dual supply rails with the controller
operating from 12V and the power FETs from 5V.
Pinout
Features
• Pentium® II Compatible
• 5 bit DAC Controlled Output Voltage
• Greater than 90% Efficiency
• 4.5V to 12.6V Input Range
• Dual NMOS Power FET Drivers
• Fixed frequency, Current Mode Control
• Adjustable Oscillator with External Sync. Capability
• Synchronous Switching
• Internal Soft-Start
• User Adjustable Slope Compensation
• Pulse by Pulse Current Limiting
• 1% Typical Output Accuracy
• Power Good Signal
• Output Power Down
• Over Voltage Protection
• Pb-Free Available (RoHS Compliant)
Applications
• Pentium® II Voltage Regulation Modules (VRMs)
• PC Motherboards
• DC/DC Converters
• GTL Bus Termination
• Secondary Regulation
1
2
3
4
16
15
14
13
5
6
7
12
11
9
8
10
20
19
18
17
OTEN
VID4
VID3
VID2
VID1
VIDO
PWRGD
REF
COSC
CSLOPE
VH1
FB
CS
GND
GNDP
LSD
VINP
VIN
LX
HSD
ENABLE
POWER
GOOD
Voltage
I.D. (VID
(0:4))
C3 240pF
C3 240pF
C3
0.1µF
1.4V
C6 0.1µF
R2
5
D1
Q1
C8
1µF
C1
1000µ
F x3
L2
1.5µH
4.5V
to
12.6V
L1
5.1µH
R2
5
C2
1000µF
x6
C7
1µF
Q2
D2
V
OUT
1.3V to
3.5V
Q1, Q2: Siliconix, Si4410, x2
C1: Sanyo, 16MV 1000GX, 1000µF x3
C2: Sanyo, 6MV 1000GX, 1000µF x6
L1: Pulse Engineering, PE-53700, 5.1µH
L2: Micrometals, T30-26, 7T AWG #20, 1.5µH
R1: Dale, WSL-25-12, 15m, x2
D1: BAV99
D2: IR, 32CTQ030
Ordering Information
PART NUMBER PACKAGE
TAPE AND
REEL PKG. DWG. #
EL7571CM 20-Pin SO - MDP0027
EL7571CM-T13 20-Pin SO 13” MDP0027
EL7571CMZ
(See Note)
20-Pin SO
(Pb-free)
- MDP0027
EL7571CMZ-T13
(See Note)
20-Pin SO
(Pb-free)
13” MDP0027
NOTE: Intersil Pb-free products employ special Pb-free material
sets; molding compounds/die attach materials and 100% matte tin
plate termination finish, which are RoHS compliant and compatible
with both SnPb and Pb-free soldering operations. Intersil Pb-free
products are MSL classified at Pb-free peak reflow temperatures that
meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020C.
