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L6997S
June 2004
1
Features
■
FROM 3V TO 5.5V VCC RANGE
■
MINIMUM OUTPUT VOLTAGE AS LOW AS
0.6V
■
1V TO 35V INPUT VOLTAGE RANGE
■
CONSTANT ON TIME TOPOLOGY
■
VERY FAST LOAD TRANSIENTS
■
0.6V, ±1% VREF
■
SELECTABLE SINKING MODE
■
LOSSLESS CURRENT LIMIT, AVAILABLE
ALSO IN SINKING MODE
■
REMOTE SENSING
■
OVP,UVP LATCHED PROTECTIONS
■
600
A TYP QUIESCENT CURRENT
■
POWER GOOD AND OVP SIGNALS
■
PULSE SKIPPING AT LIGTH LOADS
■
94% EFFICIENCY FROM 3.3V TO 2.5V
2
Applications
■
NETWORKING
■
DC/DC MODULES
■
DISTRIBUTED POWER
■
MOBILE APPLICATIONS
■
CHIP SET, CPU, DSP AND MEMORIES
SUPPLY
3
Description
The device is a high efficient solution for networking
dc/dc modules and mobile applications compatible
with 3.3V bus and 5V bus.
It's able to regulate an output voltage as low as 0.6V.
The constant on time topology assures fast load tran-
sient response. The embedded voltage feed-forward
provides nearly constant switching frequency opera-
tion in spite of a wide input voltage range.
An integrator can be introduced in the control loop to
reduce the static output voltage error.
The remote sensing improves the static and dynamic
regulation, recovering the wires voltage drop.
Pulse skipping technique reduces power consump-
tion at light loads. Drivers current capability allows
output currents in excess of 20A.
STEP DOWN CONTROLLER
FOR LOW VOLTAGE OPERATIONS
Figure 2. Minimum Component Count Application
L6997S
SHDN
3.3V
INT
VDR
VSENSE
OVP
Vref
GND
GNDSENSE
VFB
VCC
SS
OSC
0.6V
PGOOD
PGND
LGATE
PHASE
HGATE
ILIM
BOOT
Rilim
Css
Cvref
HS
LS
Rin1
Rin2
Cin
Cboot
Dboot
L
Cout
Ro1
Ro2
DS
REV. 1
Figure 1. Package
Table 1. Order Codes
Part Number
Package
L6997S
TSSOP20
L6997STR
Tape & Reel
TSSOP20