Dual Low Voltage PowerPath Switch Driver

The LTC1473L provides reliable and efficient switching between two DC power sources. This device drives two external sets of back-to-back N-channel MOSFET switches to route power to the input of a low voltage system. An internal boost regulator provides the voltage to fully enhance the logic-level N-channel MOSFET switches while an internal undervoltage lock-out circuit keeps the system alive down to 2.8V.

The LTC1473L senses current to limit inrush between the batteries and the system supply capacitor during switch-over transitions or during fault conditions. A user-programmable timer monitors the time the MOSFET switches are in current limit and latches them off when the programmed time is exceeded.

A unique “2-diode” logic mode ensures system start-up regardless of which input receives power first.

Applications

* Portable Computers

* Portable Instruments

* Fault Tolerant Computers

* Battery-Backup Systems

* 3.3V/5V Power Management

* Power Path Management for Systems with Multiple DC Sources

* Switches and Isolates Sources from 3.3V to 10V

* All N-Channel Switching to Reduce Power Losses and System Cost

* Built-In Step-Up Regulator for N-Channel Gate Drive

* Capacitor Inrush and Short-Circuit Current Limited

* User-Programmable Timer Prevents Overdissipation During Current Limiting

* Undervoltage Lockout Prevents Operation with Low Inputs

* Small Footprint: 16-Pin Narrow SSOP