LTC1155
Dual High Side
Micropower MOSFET Driver
FEATURES
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DESCRIPTIO
Fully Enhances N-Channel Power MOSFETs
8碌A(chǔ) Standby Current
85碌A(chǔ) ON Current
Short-Circuit Protection
Wide Power Supply Range: 4.5V to 18V
Controlled Switching ON and OFF Times
No External Charge Pump Components
Replaces P-Channel High Side MOSFETs
Compatible with Standard Logic Families
Available in 8-Pin SO Package
The LTC
廬
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 8碌A(chǔ)
standby current and 85碌A(chǔ) 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 鈥渟leep鈥?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.
APPLICATI
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Laptop Power Bus Switching
SCSI Termination Power Switching
Cellular Phone Power Management
P-Channel Switch Replacement
Relay and Solenoid Drivers
Low Frequency Half H-Bridge
Motor Speed and Torque Control
TYPICAL APPLICATI
Laptop Computer Power Bus Switch with Short Circuit Protection
V
S
= 4.5V TO 5.5V
R
SEN
0.02鈩?/div>
R
DLY
100k
C
DLY
0.1碌F
+
10碌F
C
DLY
0.1碌F
R
DLY
100k
R
SEN
0.02鈩?/div>
DS1
*IRLR034
5A
MAX
TTL, CMOS INPUT
POWER BUS
V
S
DS2
*IRLR034
5A
MAX
TTL, CMOS INPUT
VOLTAGE DROP (V)
G1
LTC1155
G2
IN1
GND
IN2
碌P
SYSTEM
GND
DISK
DRIVE
DISPLAY
PRINTER,
ETC.
*SURFACE MOUNT
1155 TA01
U
Switch Voltage Drop
0.25
0.20
0.15
0.10
0.05
0.00
0
1
2
OUTPUT CURRENT (A)
3
1155 TA02
UO
UO
1
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