3.3V Dual Micropower High-Side/Low-Side MOSFET Driver

The LTC1157 dual 3.3V micropower MOSFET gate driver makes it possible to switch either supply or ground reference loads through a low RDS(ON) Nchannel switch (N-channel switches are required at 3.3V because P-channel MOSFETS do not have guaranteed RDS(ON) with VGS ≤ 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.

Applications

* Notebook Computer Power Management

* Palmtop Computer Power Management

* P-Channel Switch Replacement

* Battery Charging and Management

* Mixed 5V and 3.3V Supply Switching

* Stepper Motor and DC Motor Control

* Cellular Telephones and Beepers

* Allows Lowest Drop 3.3V Supply Switching * Operates on 3.3V or 5V Nominal Supplies * 3 Microamps Standby Current * 80 Microamps ON Current * Drives Low Cost N-Channel Power MOSFETs * No External Charge Pump Components * Controlled Switching ON and OFF Times * Compatible with 3.3V and 5V Logic Families * Available in 8-Pin SOIC