Features

• Tracks Multiple Supplies with MOSFET Switches
• Monitors 5 Input Voltages Including V_CC
• Guaranteed Threshold Accuracy: ±1% at 0.5V
• Automatic Remote Sense Switching
• Adjustable Supply Ramp Rate
• Overvoltage Monitor
• Adjustable Electronic Circuit Breaker
• Adjustable Power-Good Delay
• Available for V_CC Supply Voltages of 5V, 3.3V and 2.5V
• Available in 16-Pin Narrow SSOP (LTC2921 Series) and 20-Pin TSSOP (LTC2922 Series)

Typical Application

Description

The LTC2921 and LTC2922 monitor up to five supplies and force them to track on power-up in multiple supply systems. Using external N-channel pass transistors, the supplies can be ramped up at an adjustable rate. Automatic remote sense switching allows the DC/DC converters to compensate for series voltage drops in the wiring. An incorrect level on one or more of the supplies triggers disconnect of all supplies. Tight 1% accuracy and glitch immunity on the low 0.5V monitoring level ensure no false error disconnects.

The LTC2921 and LTC2922 each feature an adjustable electronic circuit breaker to protect the V_CC supply against short circuits. Capacitance at the TIMER pin programs the delays in the monitoring sequence.

The LTC2921 includes three remote sense switches in a 16-pin narrow SSOP package, while the LTC2922 includes five remote sense switches in a 20-pin TSSOP package. Both parts are available for V_CC supply voltages of 5V, 3.3V, and 2.5V.