LTC1177-5/LTC1177-12
Isolated MOSFET Drivers
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DESCRIPTIO
EATURE
S
F
The LTC®1177-5/LTC1177-12 are isolated high side
MOSFET drivers. When used with an external N-channel
MOSFET, the LTC1177-5/LTC1177-12 form an isolated
solid state switch for reliable bounce-free switching op-
eration. The output does not require an auxiliary power
supply to maintain an on-state condition.
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UL Recognized
File E151738 to UL1577
No Secondary Power Supply
Drives Any Logic Level FET
Low Input Current: 1mA Typ (LTC1177-5),
2.5mA Typ (LTC1177-12)
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Turns On in 1ms Typ and Turns Off in 1ms Typ
2500VRMS of Isolation Voltage
Isolates Input from High Voltage Transients at Load
Clean, Bounce-Free Switching
Current Limit
Two lead frame capacitors are used to transfer energy
fromtheinputtodrivethegateoftheMOSFETandprovide
the necessary isolation. Unlike optoisolated FET drivers,
the input current for the LTC1177-5 is only 1mA and
2.5mA for LTC1177-12. It also does not have the aging
problems endemic to optocouplers.
Small Outline Package
Both devices provide 2500VRMS (1 minute) or 3000VRMS
(1 second) of output-to-input isolation.
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PPLICATI
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A
The LTC1177-5/LTC1177-12 are available in the 18-pin
PDIP or 28-pin SW package.
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Solid State Relay
Isolated Solenoid Driver
Isolated Motor Driver
Isolated Lamp Driver
, LTC and LT are registered trademarks of Linear Technology Corporation.
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O
TYPICAL APPLICATI
Input vs Output
Isolated High Side Switch
f = 50Hz
18
1
5V OR 12V
0V
V
GND1
LTC1177-5
IN
LTC1177-12
+
V
= 40V
VOUT
ISOLATION BARRIER
12
11
10
7
8
9
+
NC
NC
GND2
47µF
50V
NC
VIN
MTD3055EL
OUT
SENSE
V
OUT
1177 TA02
R
OUT
50Ω
1177 TA01
1