Features

• Simultaneously Monitors Four (LTC2938) or Six Supplies (LTC2939)
• Sixteen User-Selectable Combinations of 5V, 3.3V, 2.5V, 1.8V, 1.5V, 1.2V and/or ± Adjustable Voltage Thresholds
• Guaranteed Threshold Accuracy: ±1.5%
• Adjustable Reset and Watchdog Timeout
• Low Supply Current: 80μA Typical
• Power Supply Glitch Immunity
• Guaranteed RST for V_CC > 1V
• High Temperature Operation to 125°C
• 12-Pin 4mm x 3mm DFN or 12-Lead MSOP (LTC2938) and 16-Lead MSOP Package (LTC2939)

Typical Application

Description

The LTC2938/LTC2939 are configurable supply monitors for systems with up to four or six supply voltages that need watchdog supervision. One of sixteen preset or adjustable voltage monitor combinations can be selected using an external resistive divider connected to the program input. The preset voltage thresholds are accurate to ±1.5% over temperature. The LTC2938 and LTC2939 also feature adjustable inputs with a 0.5V nominal threshold.

The reset and watchdog timeout periods are adjustable using external capacitors. Tight voltage threshold accuracy and glitch immunity ensure reliable reset operation without false triggering. The RST output is guaranteed to be in the correct state for V_CC down to 1V. Each status output has a weak internal pull-up and may be externally pulled up to a user-defined voltage.

The 80μA supply current makes the LTC2938 and LTC2939 ideal for power conscious systems. The LTC2939 monitors up to six supplies and the LTC2938 monitors up to four supplies.