LTC1157CS8#TR Linear Technology, LTC1157CS8#TR Datasheet - Page 4

• Manufacturer Part Number: LTC1157CS8#TR
• Description: IC DRIVER MOSFET 3.3V DUAL 8SOIC
• Manufacturer: Linear Technology

Specifications of LTC1157CS8#TR

• Configuration: High or Low Side
• Input Type: Non-Inverting
• Delay Time: 230µs
• Number Of Configurations: 2
• Number Of Outputs: 2
• Voltage - Supply: 3.3 V ~ 5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Peak: -
• High Side Voltage - Max (bootstrap): -

OPERATIO
BLOCK DIAGRA
PI FU CTIO S
LTC1157
Input Pins: The LTC1157 input pins are active high and
activate the charge pump circuitry when switched ON. The
LTC1157 logic inputs are high impedance CMOS gates
with ESD protection diodes to ground and supply and
therefore should not be forced beyond the power supply
rails.
Gate Drive Pins: The gate drive pin is either driven to
ground when the switch is turned OFF or driven above the
supply rail when the switch is turned ON. This pin is a
The LTC1157 is a dual micropower MOSFET driver de-
signed specifically for operation at 3.3V and 5V and
includes the following functional blocks:
3.3V Logic Compatible Inputs
The LTC1157 inputs have been designed to accommodate
a wide range of 3.3V and 5V logic families. Approximately
50mV of hysteresis is provided to ensure clean switching.
An ultra low standby current voltage regulator provides
continuous bias for the logic-to-CMOS converter. The
logic-to-CMOS converter output enables the rest of the
circuitry. In this way the power consumption is kept to an
absolute minimum in the standby mode.
4
U
U
INPUT
U
U
W
LOGIC-TO-CMOS
LOW STANDBY
REGULATOR
CONVERTER
CURRENT
(One Channel)
GND
V
S
OSCILLATOR
REGULATOR
FREQUENCY
VOLTAGE
HIGH
relatively high impedance when driven above the rail (the
equivalent of a few hundred k ). Care should be taken to
minimize any loading of this pin by parasitic resistance to
ground or supply.
Supply Pin: The supply pin of the LTC1157 should never
be forced below ground as this may result in permanent
damage to the device . A 300 resistor should be inserted
in series with the ground pin if negative supply voltage
transients are anticipated.
Gate Charge Pump
Gate drive for the power MOSFET is produced by an
internal charge pump circuit which generates a gate volt-
age substantially higher than the power supply voltage.
The charge pump capacitors are included on-chip and
therefore no external components are required to generate
the gate drive.
Controlled Gate Rise and Fall Times
When the input is switched ON and OFF, the gate is
charged by the internal charge pump and discharged in a
controlled manner. The charge and discharge rates have
been set to minimize RFI and EMI emissions.
DISCHARGE
CHARGE
PUMP
LOGIC
GATE
LTC1157 • BD
GATE