LTC1154 Linear Technology, LTC1154 Datasheet - Page 6

• Manufacturer Part Number: LTC1154
• Description: High-Side Micropower MOSFET Driver
• Manufacturer: Linear Technology

LTC1154
PI FU CTIO S
Drain Sense Pin
The drain sense pin is compared against the supply pin
voltage. If the voltage at this pin is more than 100mV below
the supply pin, the input latch will be reset and the MOSFET
gate will be quickly discharged. Cycle the input, or ENABLE
input, to reset the short-circuit latch and turn the MOSFET
back on.
This pin is also a high impedance CMOS gate with ESD
protection and therefore should not be forced beyond the
power supply rails. To defeat the over current protection,
short the drain sense to supply.
Some loads, such as large supply capacitors, lamps, or
motors require high in-rush currents. An RC time delay
can be added between the sense resistor and the drain
STATUS
6
ENABLE
BLOCK
INPUT
U
U
LOW STANDBY
TTL-TO-CMOS
REGULATOR
CONVERTER
CURRENT
I D AGRA
GND
V
S
U
W
ANALOG
ANALOG SECTION
REGULATORS
REFERENCE
VOLTAGE
100mV
DIGITAL
COMP
SHOT
ONE
FAULT DETECTION
OUTPUT DRIVER
AND STATUS
DELAY
10 s
sense pin to ensure that the drain sense circuitry does not
false-trigger during start-up. This time constant can be set
from a few microseconds to many seconds. However, very
long delays may put the MOSFET in risk of being destroyed
by a short-circuit condition. (see Applications Information
Section).
Status Pin
The status pin is an open-drain output which is driven low
whenever a fault condition is detected. A 51k pull-up
resistor should be connected between this output and a
logic supply. The status pins of multiple LTC1154s can be
OR’d together if independent fault sensing is not required.
No connection is required to this pin when not in use.
R
S
LATCH
INPUT
AND DISCHARGE
CONTROL LOGIC
TTL-TO-CMOS
GATE CHARGE
AND CHARGE
OSCILLATOR
SHUTDOWN
CONVERTER
PUMP
GATE CHARGE
FAST/SLOW
LOGIC
DRAIN
SENSE
SHUTDOWN
GATE
LTC1154 • BD01