L6995S Datasheet, PDF (1/26 Pages) STMicroelectronics – LOSSLESS CURRENT LIMIT

L6995S
STEP DOWN CONTROLLER FOR HIGH DIFFERENTIAL
INPUT-OUTPUT CONVERSION
1 FEATURES
Figure 1. Package
■ CONSTANT ON TIME TOPOLOGY ALLOWS
OPERATION WITH LOWER DUTY THAN
PWM TOPOLOGY
■ VERY FAST LOAD TRANSIENTS
TSSOP20
■ 5V V_cc SUPPLY
■ 1.5V TO 35V INPUT VOLTAGE RANGE
Table 1. Order Codes
■ 0.9V ±1% V_REF
Part Number
Package
■ MINIMUM OUTPUT VOLTAGE AS LOW AS 0.9V
) _{■ SELECTABLE SINKING MODE}
t(s ^{■ LOSSLESS CURRENT LIMIT}
c ■ REMOTE SENSING
u _{■ OVP,UVP LATCHED PROTECTIONS}
rod ^{■ 600µA TYP QUIESCENT CURRENT}
■ POWER GOOD AND OVP SIGNALS
P _{■ PULSE SKIPPING AT LIGHT LOADS}
lete ^{2 APPLICATIONS}
o _{■ I/O BUS FOR CPU CORE SUPPLY}
s _{■ NOTEBOOK COMPUTERS}
Ob ^{■ NETWORKING DC-DC}
- ■ DISTRIBUTED POWER
L6995S
L6995STR
TSSOP20
Tape & Reel
3 DESCRIPTION
The device is a step-down controller specifically de-
signed to provide extremely high efficiency conver-
sion, with losses current sensing tecnique.
The "constant on-time" topology assures fast load
transient response. The embedded "voltage feed-for-
ward" provides nearly constant switching frequency
operation.
An integrator can be introduced in the control loop to
reduce the static output voltage error.
The available remote sensing improve the static and
dynamic regulation recovering the wires voltage
drop. Pulse skipping technique reduces power con-
sumption at light load. Drivers current capability al-
lows output current in excess of 20A.
t(s) _{Figure 2. Minimum Component Count Application}
uc _35V
d _Rin2
Rin1
ro 5V
CIN
P _OSC
BOOT
te _HGATE
5V
D
C
BOOT
HS
BOOT
bsole _RILIM
O ILIM
PHASE
LGATE
PGND
LS
DS
L
C_OUT
Vo
0.9V
L6995S ^GND
NOSKIP
VSENSE
SS
C_SS
INT
VFB
VREF
C_VREF
April 2004
REV. 1
1/26