Low-Power μP Supervisory Circuits with Battery-Backup Circuit and Chip-Enable Gating

The MAX16016/MAX16020/MAX16021 supervisory circuits monitor power supplies, provide battery-backup control, and chip-enable (CE) gating to write protect memory in microprocessor (µP)-based systems. These low-power devices improve system reliability by providing several supervisory functions in a small, single integrated solution.

The MAX16016/MAX16020/MAX16021 perform four basic system functions:

* Provide a µP reset output during VCC supply power-up, power-down, and brownout conditions.

* Control VCC to battery-backup switching internally to maintain data or low-power operation for memories, real-time clocks (RTCs), and other digital logic when the main power is removed.

* Provide memory write protection through internal chip-enable gating during brownout.

* Provide a combination of additional supervisory functions listed in the Features section in the full data sheet.

The MAX16016/MAX16020/MAX16021 operate from a 1.53V to 5.5V supply voltage and offer fixed reset thresholds for monitoring 5V, 3.3V, 3V, 2.5V, and 1.8V systems. Each device is available with either a push-pull or open-drain reset output.

The MAX16016/MAX16020/MAX16021 are available in small TDFN/TQFN packages and are fully specified for an operating temperature range of -40°C to +85°C.

Applications

* GPS Systems * Industrial Control * Main/Backup Power for RTCs, CMOS Memories * Point-of-Sale Equipment * Portable/Battery Equipment * Set-Top Boxes

* System Monitoring for 5V, 3.3V, 3V, 2.5V, or 1.8V Power-Supply Voltages

* 1.53V to 5.5V Operating Voltage Range

* Low 1.2µA Supply Current (0.25µA in Battery-Backup Mode)

* 145ms (min) Reset Timeout Period

* Battery Freshness Seal

* On-Board Gating of CE Signals, 1.5ns Propagation Delay (MAX16020/MAX16021)

* Debounced Manual Reset Input

* Watchdog Timer, 1.2s (typ) Timeout

* Power-Fail Comparator and Low-Line Indicator for Monitoring Voltages Down to 0.6V

* Battery-On, Battery-OK, and Battery Test Indicators

* Small 10-Pin TDFN or 16-Pin TQFN Packages