LTC1155 Datasheet, PDF (1/16 Pages) Linear Technology – Dual High Side Micropower MOSFET Driver

FEATURES
s _{Fully Enhances N-Channel Power MOSFETs}
s _{8µA Standby Current}
s _{85µA ON Current}
s _{Short-Circuit Protection}
s _{Wide Power Supply Range: 4.5V to 18V}
s _{Controlled Switching ON and OFF Times}
s _{No External Charge Pump Components}
s _{Replaces P-Channel High Side MOSFETs}
s _{Compatible with Standard Logic Families}
s _{Available in 8-Pin SO Package}
APPLICATI S
s _{Laptop Power Bus Switching}
s _{SCSI Termination Power Switching}
s _{Cellular Phone Power Management}
s _{P-Channel Switch Replacement}
s _{Relay and Solenoid Drivers}
s _{Low Frequency Half H-Bridge}
s _{Motor Speed and Torque Control}
LTC1155
Dual High Side
Micropower MOSFET Driver
DESCRIPTIO
The LTC^®1155 dual high side gate driver allows using low
cost N-channel FETs for high side switching applications.
An internal charge pump boosts the gate above the posi-
tive rail, fully enhancing an N-channel MOSFET with no
external components. Micropower operation, with 8µA
standby current and 85µA operating current, allows use in
virtually all systems with maximum efficiency.
Included on-chip is overcurrent sensing to provide auto-
matic shutdown in case of short circuits. A time delay can
be added in series with the current sense to prevent false
triggering on high in-rush loads such as capacitors and
incandescent lamps.
The LTC1155 operates off of a 4.5V to 18V supply input
and safely drives the gates of virtually all FETs. The
LTC1155 is well suited for low voltage (battery-powered)
applications, particularly where micropower “sleep” op-
eration is required.
The LTC1155 is available in both 8-pin PDIP and 8-pin SO
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATI
Laptop Computer Power Bus Switch with Short Circuit Protection
R_SEN
0.02Ω
R_DLY
100k
V_S = 4.5V TO 5.5V
C_DLY
0.1µF
+
10µF
DS1
V_S
DS2
C_DLY
0.1µF
R_DLY
100k
*IRLR034
5A
MAX
TTL, CMOS INPUT
G1 LTC1155 G2
IN1 GND IN2
*IRLR034
TTL, CMOS INPUT
R_SEN
0.02Ω
5A
MAX
POWER BUS
µP
SYSTEM
DISK
DRIVE
GND
*SURFACE MOUNT
DISPLAY
PRINTER,
ETC.
1155 TA01
Switch Voltage Drop
0.25
0.20
0.15
0.10
0.05
0.00
0
1
2
OUTPUT CURRENT (A)
3
1155 TA02
1