L6911E Datasheet, PDF (1/20 Pages) STMicroelectronics – 5 BIT PROGRAMMABLE STEP DOWN CONTROLLER WITH SYNCHRONOUS RECTIFICATION

L6911E
5 BIT PROGRAMMABLE STEP DOWN CONTROLLER
WITH SYNCHRONOUS RECTIFICATION
s OPERATING SUPPLY IC VOLTAGE FROM 5V
TO 12V BUSES
s UP TO 1.3A GATE CURRENT CAPABILITY
s TTL-COMPATIBLE 5 BIT PROGRAMMABLE
OUTPUT COMPLIANT WITH VRM 8.5 :
1.050V TO 1.825V WITH 0.025V BINARY
STEPS
s VOLTAGE MODE PWM CONTROL
s EXCELLENT OUTPUT ACCURACY: ±1%
OVER LINE AND TEMPERATURE
VARIATIONS
s VERY FAST LOAD TRANSIENT RESPONSE:
FROM 0% TO 100% DUTY CYCLE
s POWER GOOD OUTPUT VOLTAGE
s OVERVOLTAGE PROTECTION AND
MONITOR
s OVERCURRENT PROTECTION REALIZED
USING THE UPPER MOSFET’S RdsON
s 200KHz INTERNAL OSCILLATOR
s OSCILLATOR EXTERNALLY ADJUSTABLE
FROM 50KHz TO 1MHz
s SOFT START AND INHIBIT FUNCTIONS
APPLICATIONS
s POWER SUPPLY FOR ADVANCED
MICROPROCESSOR CORE
s DISTRIBUTED POWER SUPPLY
BLOCK DIAGRAM
Vcc 5V to12V
November 2001
PGOOD
SS
OVP
RT
VD0
VD1
VD2
VD3
VD4
VCC
OCSET
MONITOR and
PROTECTION
OSC
D/A
+
-
+
PWM
-
E/A
D98IN957
COMP
SO-20
ORDERING NUMBERS: L6911E
L6911ETR (Tape and Reel)
DESCRIPTION
The device is a power supply controller specifically
designed to provide a high performance DC/DC con-
version for high current microprocessors. A precise 5
bit digital to analog converter (DAC) allows to adjust
the output voltage from 1.050 to 1.825 with 25mV bi-
nary steps.
The high precision internal reference assures the se-
lected output voltage to be within ±1%. The high peak
current gate drive affords to have fast switching to the
external power mos providing low switching losses.
The device assures a fast protection against load
overcurrent and load over-voltage. An external SCR
is triggered to crowbar the input supply in case of
hard overvoltage. An internal crowbar is also provid-
ed turning on the low side mosfet as long as the over-
voltage is detected. In case of over-current detection,
the soft start capacitor is discharged an the system
works in HICCUP mode.
BOOT
UGATE
PHASE
LGATE
PGND
GND
VSEN
VFB
Vin 5V to12V
Vo
1.050V to 1.825V
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