LT1158CS View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LT1158CS' PDF : 20 Pages View PDF
TYPICAL PERFORMANCE CHARACTERISTICS
Top Gate Rise Time
400
350
300
CGATE = 10000pF
250
200
CGATE = 3000pF
150
100
CGATE = 1000pF
50
0
0 5 10 15 20 25 30 35 40
SUPPLY VOLTAGE (V)
LT1158 G13
Top Gate Fall Time
400
350
300
CGATE = 10000pF
250
200
150
CGATE = 3000pF
100
CGATE = 1000pF
50
0
0 5 10 15 20 25 30 35 40
SUPPLY VOLTAGE (V)
LT1158 G14
LT1158
Transition Times vs RGate
800
V+ = 12V
700 CGATE = 3000pF
600
500
RISE TIME
400
FALL TIME
300
200
100
0
0 10 20 30 40 50 60 70 80 90 100
GATE RESISTANCE (Ω)
LT1158 G15
PI FU CTIO S
Pin 1 (Boost Drive): Recharges and clamps the bootstrap
capacitor to 14.5V higher than pin 13 via an external diode.
Pin 2 (V+): Main supply pin; must be closely decoupled to
the ground pin 7.
Pin 3 (Bias): Decouple point for the internal 2.6V bias
generator. Pin 3 cannot have any external DC loading.
Pin 4 (Enable): When left open, the LT1158 operates
normally. Pulling pin 4 low holds both MOSFETs off
regardless of the input state.
Pin 5 (Fault): Open collector NPN output which turns on
when V12 – V11 exceeds the fault conduction threshold.
Pin 6 (Input): Taking pin 6 high turns the top MOSFET on
and bottom MOSFET off; pin 6 low reverses these states.
An input latch captures each low state, ignoring an ensu-
ing high until pin 13 has gone below 2.6V.
Pin 8 (Bottom Gate Feedback): Must connect directly to
the bottom power MOSFET gate. The top MOSFET turn-on
is inhibited until pin 8 has discharged to 1.5V. A hold-on
current source also feeds the bottom gate via pin 8.
Pin 9 (Bottom Gate Drive): The high current drive point
for the bottom MOSFET. When a gate resistor is used, it is
inserted between pin 9 and the gate of the MOSFET.
Pin 10 (V+): Bottom side driver supply; must be con-
nected to the same supply as pin 2.
Pin 11 (Sense Negative): The floating reference for the
current limit comparator. Connects to the low side of a
current shunt or Kelvin lead of a current-sensing MOSFET.
When pin 11 is within 1.2V of V+, current limit is inhibited.
Pin 12 (Sense Positive): Connects to the high side of the
current shunt or sense lead of a current-sensing MOSFET.
A built-in offset between pins 11 and 12 in conjunction
with RSENSE sets the top MOSFET short-circuit current.
Pin 13 (Top Source): Top side driver return; connects to
MOSFET source and low side of the bootstrap capacitor.
Pin 14 (Top Gate Feedback): Must connect directly to the
top power MOSFET gate. The bottom MOSFET turn-on is
inhibited until V14 – V13 has discharged to 1.75V. An on-
chip charge pump also feeds the top gate via pin 14.
Pin 15 (Top Gate Drive): The high current drive point for
the top MOSFET. When a gate resistor is used, it is inserted
between pin 15 and the gate of the MOSFET.
Pin 16 (Boost): Top side driver supply; connects to the
high side of the bootstrap capacitor and to a diode either
from supply (V+ < 10V) or from pin 1 (V+ > 10V).
5
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