4

LTC1477/LTC1478

LTC1477

EN (Pin 4): The enable input is a high impedance CMOS

gate with an ESD protection diode to ground and should

not be forced below ground. This input has about 100mV

of built-in hysteresis to ensure clean switching.

the current limit and thermal shutdown circuitry; plus

provides a sense connection to the input power supply.

The gate of the NMOS switch is powered by a charge pump

supply pin provides connection to the drain of 1/2 of the

output power device.

together the entire power device is connected (see Block

the short-circuit current limit at the expense of higher

details.)

always be tied together. The output is protected against

accidental short circuits to ground by a current limit circuit

which protects the system power supply and load against

damage. A second level of protection is provided by

thermal shutdown circuitry which limits the die tempera-

ture to 130

°C.

LTC1478

AEN, BEN (Pins 4,12): The enable inputs are high imped-

ance CMOS gates with ESD protection diodes to ground

and should not be forced below ground. These inputs

have about 100mV of built-in hysteresis to ensure clean

switching.

logic, the current limit and thermal shutdown circuitry;

plus, provides a sense connection to the input power

supply. The gate of the NMOS switch is powered by a

connection to the drain of 1/2 of the output power device.

nected together the entire power device is connected (see

nected to reduce the short-circuit current limit at the

section for more details.)

are protected against accidental short circuits to ground

by a current limit circuit which protects the system power

supplies and loads against damage. A second level of

protection is provided by thermal shutdown circuitry

which limits the die temperature to approximately 130

°C.