CS51312
CS51312
Synchronous CPU Buck Controller
for 12V Only Applications
Description
The CS51312 is a synchronous dual
NFET Buck Regulator Controller. It is
designed to power the core logic of
the latest high performance CPUs and
ASICs from a single 12V input. It uses
TM
the V
2
control method to achieve
the fastest possible transient response
and best overall regulation. It incor-
porates many additional features
required to ensure the proper opera-
tion and protection of the CPU and
Power system. The CS51312 provides
the industry’s most highly integrated
solution, minimizing external compo-
nent count, total solution size, and
cost.
The CS51312 is specifically designed
to power Intel’s Pentium
®
II processor
and includes the following features:
5-bit DAC with 1.2% tolerance,
Power-Good output, overcurrent hic-
cup mode protection, overvoltage
protection, V
CC
monitor, Soft Start,
adaptive voltage positioning, adap-
tive FET non-overlap time, and
remote sense. The CS51312 will oper-
ate over a 9V to 20V (V
CC2
) range
using either single or dual input volt-
age and is available in 16 lead narrow
body surface mount package.
Features
s
Synchronous Switching
Regulator Controller for CPU
V
CORE
s
Dual N-Channel MOSFET
Synchronous Buck Design
s
V
2
TM
Control Topology
s
200ns Transient Loop Response
s
5 bit DAC with 1.2% Tolerance
s
Hiccup Mode Overcurrent
Protection
s
40ns Gate Rise and Fall Times
(3.3nF load)
s
65ns Adaptive FET Non-overlap
Time
s
Adaptive Voltage Positioning
s
Power-Good Output Monitors
Regulator Output
s
5V/12V or 12V-only Operation
s
V
CC
Monitor Provides Under
Voltage Lockout
s
OVP Output Monitors Regulator
Output
s
Multifunction COMP Pin
Provides ENABLE, Soft Start,
and Hiccup Timing in
Addition to Control Loop
Compensation
Application Diagram
12V
C1
1.0µF
D1
SS16GICT-ND
C2 C3 C4
+
+
+
12V
R1
22Ω
D2
ZM4746ACT-ND
R2
200
C9
0.01µF
220µF
16SV220
FY10AAJ-03A
Q1
R3
FY10AAJ-03A
Q2
FY10AAJ-03A
10
12
11
13
14
C6
0.010µF
C11 C12 C13
L1
1.2µH
R4
0.004Ω
+
+
+
+
+
Package Options
470µF
C10
1µF
10k
15
16
1
2
3
4
5
9
8
16 Lead SO Narrow
VID0
VID1
1
C19
1000pF
ENABLE
C
OFF
V
CC2
V
CC1
V
FB
COMP
V
ID0
GATE(H)
GATE(L)
V
ID1
CS51312
V
ID2
Gnd
OVP
V
ID3
V
ID4
V
OUT
PWRGD
7
6
Q3
1.25V to 3.5V
470µF
T510X477K006AS4394
C14 C15
COMP
C
OFF
PWRGD
OVP
GATE(L)
Gnd
GATE(H)
V
CC2
FY10AAJ-03A
OVP
1
1
VID2
VID3
VID4
Q4
DAC
PWRGD
D3
SS12GICT-ND
V
FB
V
OUT
V
CC1
12V to 16A high performance converter.
V
2
is a trademark of Switch Power, Inc.
Pentium is a registered trademark of Intel Corporation.
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
Rev. 3/11/99
1
A
®
Company
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
