LTC1157_15 Datasheet, PDF (1/8 Pages) Linear Technology – 3.3V Dual Micropower High-Side/Low-Side MOSFET Driver

LTC1157
3.3V Dual Micropower
High-Side/Low-Side MOSFET Driver
FEATURES
s _{Allows Lowest Drop 3.3V Supply Switching}
s _{Operates on 3.3V or 5V Nominal Supplies}
s _{3 Microamps Standby Current}
s _{80 Microamps ON Current}
s _{Drives Low Cost N-Channel Power MOSFETs}
s _{No External Charge Pump Components}
s _{Controlled Switching ON and OFF Times}
s _{Compatible with 3.3V and 5V Logic Families}
s _{Available in 8-Pin SOIC}
APPLICATI S
s _{Notebook Computer Power Management}
s _{Palmtop Computer Power Management}
s _{P-Channel Switch Replacement}
s _{Battery Charging and Management}
s _{Mixed 5V and 3.3V Supply Switching}
s _{Stepper Motor and DC Motor Control}
s _{Cellular Telephones and Beepers}
DESCRIPTIO
The LTC1157 dual 3.3V micropower MOSFET gate driver
makes it possible to switch either supply or ground
reference loads through a low R_DS(ON) N-channel switch
(N-channel switches are required at 3.3V because P-
channel MOSFETs do not have guaranteed R_DS(ON) with
V_GS ≤ 3.3V). The LTC1157 internal charge pump boosts
the gate drive voltage 5.4V above the positive rail (8.7V
above ground), fully enhancing a logic level N-channel
switch for 3.3V high-side applications and a standard N-
channel switch for 3.3V low-side applications. The gate
drive voltage at 5V is typically 8.8V above supply (13.8V
above ground), so standard N-channel MOSFET switches
can be used for both high-side and low-side applications.
Micropower operation, with 3µA standby current and
80µA operating current, makes the LTC1157 well suited
for battery-powered applications.
The LTC1157 is available in both 8-pin DIP and SOIC.
TYPICAL APPLICATI
Ultra Low Voltage Drop 3.3V Dual High-Side Switch
3.3V
+
10µF
3.3V
LOGIC
V_S
IN1
(8.7V)
G1
LTC1157
(8.7V)
IN2
G2
GND
IRLR024
IRLR024
3.3V
LOAD
LTC1157 • TA01
3.3V
LOAD
Gate Voltage Above Supply
12
10
8
6
4
2
0
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE (V)
LTC1157 • TA02
1