LTC1157
3.3V Dual Micropower
High-Side/Low-Side MOSFET Driver
DESCRIPTIO
FEATURES
n
Allows Lowest Drop 3.3V Supply Switching The LTC1157 dual 3.3V micropower MOSFET gate driver
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Operates on 3.3V or 5V Nominal Supplies makes it possible to switch either supply or ground
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3 Microamps Standby Current reference loads through a low R N-channel switch
DS(ON)
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80 Microamps ON Current (N-channel switches are required at 3.3V because P-
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Drives Low Cost N-Channel Power MOSFETs channel MOSFETs do not have guaranteed R with
DS(ON)
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No External Charge Pump Components V 3.3V). The LTC1157 internal charge pump boosts
GS
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Controlled Switching ON and OFF Times the gate drive voltage 5.4V above the positive rail (8.7V
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Compatible with 3.3V and 5V Logic Families above ground), fully enhancing a logic level N-channel
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Available in 8-Pin SOIC 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
APPLICATI S
above ground), so standard N-channel MOSFET switches
n can be used for both high-side and low-side applications.
Notebook Computer Power Management
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Palmtop Computer Power Management
Micropower operation, with 3A standby current and
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P-Channel Switch Replacement
80A operating current, makes the LTC1157 well suited
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Battery Charging and Management
for battery-powered applications.
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Mixed 5V and 3.3V Supply Switching
The LTC1157 is available in both 8-pin DIP and SOIC.
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Stepper Motor and DC Motor Control
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Cellular Telephones and Beepers
TYPICAL APPLICATI
Ultra Low Voltage Drop 3.3V Dual High-Side Switch Gate Voltage Above Supply
12
3.3V
10
+
10F
8
6
V
S
(8.7V)
IN1 G1 IRLR024
3.3V
LTC1157 4
LOGIC
(8.7V) 3.3V
IN2 G2 IRLR024
LOAD
GND
2
3.3V
LOAD
LTC1157 TA01
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
GATE VOLTAGE SUPPLY VOLTAGE (V)
O
U
UO
ULTC1157
ABSOLUTEXAI U RATI GS
Supply Voltage ........................................... 0.3V to 7V Operating Temperature Range
Any Input Voltage ............. (V + 0.3V) to (GND 0.3V) LTC1157C............................................... 0C to 70C
S
Any Output Voltage ............. (V + 12V) to (GND 0.3V) Storage Temperature Range ................ 65C to 150C
S
Current (Any Pin)................................................. 50mA Lead Temperature (Soldering, 10 sec)................. 300C
PACKAGE/ORDER I FOR ATIO
ORDER PART
ORDER PART
TOP VIEW TOP VIEW
NUMBER NUMBER
NC
1
8
NC
NC
1
8
NC
GATE 1
2
7
GATE 2
GATE 1
2
7
GATE 2
LTC1157CN8 LTC1157CS8
GND
3
6
V
GND
3
6
V
S S
IN1 4 5
IN2 IN1 4 5 IN2
S8 PART MARKING
N8 PACKAGE
S8 PACKAGE
8-LEAD PLASTIC DIP 8-LEAD PLASTIC SO
1157
T = 100C, = 130C/ W T = 100C, = 150C/ W
JMAX JA JMAX JA
ELECTRICAL CHARACTERISTICS V = 2.7V to 5.5V, T = 25C, unless otherwise noted.
S A
LTC1157C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I Quiescent Current OFF V = 3.3V, V = V = 0V (Note 1) 3 10 A
Q S IN1 IN2
Quiescent Current ON V = 3.3V, V = 3.3V (Note 2) 80 160 A
S IN
= 5V, V = 5V (Note 2) 180 400 A
V
S IN
V Input High Voltage l 70% V V
INH S
V Input Low Voltage l 15% V V
INL S
I Input Current 0V V V l 1 A
IN IN S
C Input Capacitance 5pF
IN
V V Gate Voltage Above Supply V = 3V l 4.0 4.7 6.5 V
GATE S S
V = 3.3V l 4.5 5.4 7.0 V
S
V = 5V l 7.5 8.8 12.0 V
S
t Turn-ON Time V = 3.3V, C = 1000pF
ON S GATE
Time for V > V + 1V 30 130 300 s
GATE S
Time for V > V + 2V 75 240 750 s
GATE S
V = 5V, C = 1000pF
S GATE
Time for V > V + 1V 30 85 300 s
GATE S
Time for V > V + 2V 75 230 750 s
GATE S
t Turn-OFF Time V = 3.3V, C = 1000pF
OFF S GATE
Time for V < 0.5V 10 36 60 s
GATE
V = 5V, C = 1000pF
S GATE
Time for V < 0.5V 10 31 60 s
GATE
The l denotes specifications which apply over the full operating
temperature range.
Note 1: Quiescent current OFF is for both channels in OFF condition.
Note 2: Quiescent current ON is per driver and is measured independently.
2
U
WU
U W W W