L6911C Datasheet, PDF (1/20 Pages) STMicroelectronics – 5 BIT PROGRAMMABLE STEP DOWN CONTROLLER WITH SYNCHRONOUS RECTIFICATION

L6911C
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 8.4 :
1.3V TO 2.05V WITH 0.05V BINARY STEPS
2.1V TO 3.5V WITH 0.1V 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 R_dsON
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
s HIGH POWER DC-DC REGULATORS
BLOCK DIAGRAM
Vcc 5 to 12V
November 2001
PGOOD
SS
OVP
RT
VD0
VD1
VD2
VD3
VD4
VCC
OCSET
MONITOR and
PROTECTION
OSC
D/A
+
-
+
PWM
-
E/A
D01IN1260
COMP
SO-20
ORDERING NUMBERS: L6911C
L6911CTR (Tape and Reel)
DESCRIPTION
The device is a power supply controller specifically de-
signed to provide a high performance DC/DC conver-
sion for high current microprocessors. A precise 5-bit
digital to analog converter (DAC) allows adjusting the
output voltage from 1.30V to 2.05V with 50mV binary
steps and from 2.10V to 3.50V with 100mV binary 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 overvoltage. An external SCR is
triggered to crowbar the input supply in case of hard
over-voltage. An internal crowbar is also provided
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 and the system
works in HICCUP mode.
BOOT
UGATE
PHASE
LGATE
PGND
GND
VSEN
VFB
Vin 5V to12V
Vo
1.300V to 3.500V
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