Features

• Selects Highest Priority Valid Supply from Two Inputs
• Wide 1.8V to 18V Operating Range
• Internal Dual 2Ω, 0.5A Switches
• Low 3.6µA Operating Current
• Low 320nA V2 Current When V1 Connected to OUT
• Blocks Reverse and Cross Conduction Currents
• Reverse Supply Protection to –15V
• Built-In V2 Test with Optional V2 Disconnect
• V2 Freshness Seal/Ship Mode
• ±1.5% Accurate Adjustable Switchover Threshold
• ±2.3% Accurate V2 Monitor and Comparator
• Overcurrent and Thermal Protection
• Thermally Enhanced 12-Pin 3mm × 3mm DFN and 12-Lead Exposed Pad MSOP Packages

Typical Application

Description

The LTC®4420 is a dual input monolithic PowerPath™ prioritizer, with low operating current, that provides backup switchover for keeping critical circuitry alive during brownout and power loss conditions. Unlike diode-OR products, little current is drawn from the inactive supply even if its voltage is greater than the active supply.

Internal 2Ω, current limited PMOS switches provide power path selection from a primary input (V1) or a backup input (V2) to the output. Two adjustable voltage monitors set via external resistive dividers provide flexibility in setting V1 to V2 switchover and V2 undervoltage thresholds. V1 is monitored continuously while V2 supply monitoring includes controllable low duty cycle UV monitoring. When primary input V1 drops, the ADJ monitor causes OUT to be switched to V2. When V2 drops, it is disconnected from OUT if V2DIS is low. Fast non-overlap switchover circuitry prevents reverse and cross conduction while minimizing output droop.

Auxiliary voltage monitor CMP1 provides flexible voltage monitoring and output V2OK provides V2 undervoltage status. Freshness seal mode prevents V2 battery discharge during storage or shipment.