Analog Devices Inc./Maxim Integrated MAX808NEPA+

Overview

MAX808NEPA+ from Maxim Integrated is a precision +5V microprocessor supervisory circuit with battery switchover, low-line warning, and active-low RESET output. It features ±1.5% reset threshold accuracy (4.575V), 200ms reset timeout, 1µA standby current, and CMOS RAM write protection via CE gating. Used in portable/battery-powered equipment to ensure reliable power-up sequencing and orderly shutdown during brownout.

For engineers reviewing the MAX808NEPA+ datasheet, MAX808NEPA+ pinout, MAX808NEPA+ application, or MAX808NEPA+ equivalent, this page delivers verified functional context, validated pin roles, confirmed timing behavior (tRP = 200ms, tLL = 17µs), and real-world design implications for backup-power handoff and RAM write-cycle completion.

Technical Context

The MAX808NEPA+ integrates three independent comparators: reset (4.575V threshold), low-line (4.627V rising, 52mV above reset), and battery switchover (VBATT + 0.05V hysteresis). Its BiCMOS process enables ±1.5% voltage accuracy and 1µA battery-backup supply current while supporting 250mA VCC-to-OUT conduction and 20mA BATT-to-OUT delivery.

It implements chip-enable gating with 3ns typical propagation delay (CE IN → CE OUT), 18µs write-cycle hold time upon VCC fall, and guaranteed RESET validity down to VCC = 1V. The device operates across –40°C to +85°C and uses an 8-pin plastic DIP package with lead-free finish (+ suffix).

Key Specifications

Pinout & Package

MAX808NEPA+ uses an 8-pin plastic DIP (dual in-line package) with through-hole mounting and lead-free finish. Pin 1 is marked with a notch or dot; pin numbering follows standard DIP convention (counterclockwise from top-left corner).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX808NEPA+, MAX809SESA+ omits critical battery-handling and RAM-protection features required for portable equipment, while TPS3808G12DBVR targets lower-voltage domains and cannot replicate the 18µs write-cycle hold or 4.575V ±1.5% precision needed in industrial +5V supervisory roles.

Availability

MAX808NEPA+ is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC controllers, handheld barcode scanners, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX808NEPA+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for power, sensing, and interface applications, with emphasis on reliability and performance in harsh environments.

The MAX801/MAX808 product line was engineered specifically for +5V microprocessor systems requiring coordinated reset, battery backup, and memory write protection - targeting portable, industrial, and instrumentation markets where power integrity is mission-critical.

FAQ

What is the exact reset threshold voltage of the MAX808NEPA+?

The MAX808NEPA+ has a nominal reset threshold of 4.575V with ±1.5% accuracy over temperature and supply variations. This value is fixed by the 'N' suffix per Maxim's ordering matrix and is confirmed in the Electrical Characteristics table under VRST for MAX80_N devices. The threshold remains stable across –40°C to +85°C with typical drift of ±5mV.

Does the MAX808NEPA+ support battery switchover, and what are the conditions?

Yes, the MAX808NEPA+ supports automatic battery switchover. Switchover occurs when two conditions are met simultaneously: VCC falls below the reset threshold (4.575V) AND VCC falls below VBATT. The switchover threshold includes 50mV hysteresis (VBATT + 0.05V on rising VCC), ensuring clean transitions without oscillation during recovery.

How does the CE gating function work in the MAX808NEPA+ during a power failure?

In the MAX808NEPA+, CE gating holds CE OUT active for 18µs after VCC crosses the reset threshold downward, allowing the µP to complete an ongoing RAM write cycle. If the write finishes early, CE OUT releases immediately upon CE IN going high; otherwise, it disables after 18µs. This behavior is intrinsic to the MAX808NEPA+ and requires no external components.

Is the MAX808NEPA+ compatible with SuperCapacitors or MaxCapacitors?

Yes, the MAX808NEPA+ is explicitly designed for SuperCap™ and MaxCap™ compatibility. Its battery switchover comparator tolerates VBATT exceeding VCC during normal operation, and its hysteresis (50mV) accommodates slow-charging supercaps. No external diodes or regulators are needed - direct connection of a 0.47F supercap to BATT suffices per Figure 8 in the datasheet.

What is the guaranteed operating temperature range for the MAX808NEPA+?

The MAX808NEPA+ is rated for –40°C to +85°C operation, as indicated by the 'E' in the package code (EPA = Extended Temperature Plastic DIP). This range is validated across all electrical parameters including reset accuracy, CE propagation delay, and battery switchover hysteresis, and is documented in the Ordering Information table.