Precision Dual Voltage
Regulator Controller
a
ADM1052
GENERAL DESCRIPTION
FEATURES
The ADM1052 is a dual, precision, voltage regulator controller
intended for power rail generation and active bus termination
on personal computer motherboards. It contains a precision
1.2 V bandgap reference and two channels consisting of con-
trol amplifiers driving external power devices. Each channel has a
shutdown input to turn off amplifier output and “Hiccup Mode”
protection circuitry for the external power device.
Two Independent Controllers on One Chip
Two 2.525 V Outputs
Shutdown Inputs to Control Each Channel
ꢀ2.5% Accuracy Over Line, Load, and Temperature
Low Quiescent Current
Low Shutdown Current
Works with External N-Channel MOSFETs for Low Cost
“Hiccup Mode” Fault Protection
No External Voltage or Current Setting Resistors
Small, 8-Lead SO Package
The ADM1052 operates from a 12 V supply. This gives suffi-
cient headroom for the amplifiers to drive external N-channel
MOSFETs, operating as source-followers, as the external series
pass devices. This has the advantage that N-channel devices are
cheaper than P-channel devices of similar performance, and the
circuit is easier to stabilize than one using P-channel devices in
a common-source configuration.
APPLICATIONS
Desktop Computers
Servers
Workstations
FUNCTIONAL BLOCK DIAGRAM
3.3V
V
CC
CONTROL
AMPLIFIER
100ꢁF
ADM1052
BANDGAP
REFERENCE
FORCE 1
SENSE 1
V
CC
V
OUT1
50ꢁA
2 ꢂ 100ꢁF
SHUTDOWN
CONTROL
SHDN1
HICCUP
COMPARATOR
3.3V
CONTROL
AMPLIFIER
100ꢁF
FORCE 2
SENSE 2
V
CC
V
OUT2
2 ꢂ 100ꢁF
50ꢁA
SHUTDOWN
CONTROL
SHDN2
HICCUP
COMPARATOR
V
CC
POWER-ON
RESET
CLK/DELAY
GENERATOR
CLOCK
OSCILLATOR
GND
REV. A
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reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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© Analog Devices, Inc., 2001