Analog Devices Inc./Maxim Integrated MAX807MEUE

Overview

The MAX807MEUE from Maxim Integrated is a precision microprocessor supervisory circuit designed for +5V systems requiring reliable power-up/down monitoring, battery switchover, and watchdog protection. It features a ±1.5% accurate 4.425V reset threshold, 200ms reset timeout, 250mA VCC-mode output drive, 2ns CE-gate propagation delay, and guaranteed RESET validity down to VCC = 1V - enabling robust operation in portable, industrial, and critical embedded controllers.

For engineers reviewing the MAX807MEUE datasheet, MAX807MEUE pinout, MAX807MEUE application, or MAX807MEUE equivalent, this device delivers verified low-line comparator accuracy (±1.5% over 52mV offset), BATT OK flag with 2.265V threshold, and dual active-high/active-low reset outputs - all in a 16-pin TSSOP package suitable for space-constrained designs with strict supply sequencing requirements.

Technical Context

The MAX807MEUE integrates six independent comparators: reset (4.425V ±1.5%), low-line (4.477V ±1.5%), power-fail (2.265V), battery-OK (2.265V), battery switchover, and watchdog timeout (1.6s). Its BiCMOS process enables 70µA typical supply current in normal mode and 1µA standby in battery-backup mode while maintaining precise voltage thresholds and fast propagation delays.

It implements a state-machine-controlled chip-enable gating path with 2ns propagation delay (50Ω source, 50pF load), automatic VCC/BATT switchover with <1.2Ω on-resistance, and manual-reset input with internal 50–200µA pullup - supporting both TTL/CMOS logic interfaces and momentary switch inputs without external debounce.

Key Specifications

Pinout & Package

MAX807MEUE is housed in a 16-pin TSSOP package (4.4mm × 5mm, 0.65mm pitch), RoHS-compliant and moisture-sensitive level 1 (MSL1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX807MEUE, both alternatives omit the integrated low-line comparator, battery switchover control, and chip-enable gating - making them inadequate for applications requiring coordinated power-fail response, RAM backup management, or memory access protection during supply transients.

Availability

MAX807MEUE is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical devices, automotive telematics units, and point-of-sale terminals requiring stable component supply across extended temperature ranges (−40°C to +85°C).

Supply support for MAX807MEUE 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, automotive, and computing applications.

The MAX807 product line delivers full-featured µP supervision - integrating reset, watchdog, power-fail warning, battery switchover, and CE gating - specifically for systems demanding high-voltage-accuracy monitoring and deterministic fault recovery in mission-critical embedded environments.

FAQ

What is the reset threshold voltage for the MAX807MEUE?

The MAX807MEUE has a precision reset threshold of 4.425V with ±1.5% accuracy over temperature. This value is fixed for the 'M' variant and ensures reliable reset assertion before system-level instability occurs in +5V applications. The threshold is guaranteed across the full operating range (−40°C to +85°C) and remains valid down to VCC = 1V, making it suitable for brownout detection in battery-depleted scenarios.

Does the MAX807MEUE support battery backup for CMOS RAM?

Yes, the MAX807MEUE provides dedicated battery backup functionality. When VCC falls below VBATT − 0.2V, the device automatically switches the OUT pin from VCC to BATT, supplying up to 20mA in battery-backup mode. It includes a BATT OK flag (active-high when VBATT > 2.265V) and BATT ON output to drive external PMOS/PNP switches - enabling robust, low-leakage RAM retention during main supply loss.

How does the watchdog timer function in the MAX807MEUE?

The MAX807MEUE watchdog timer asserts WDO low if the WDI input remains static (high or low) for longer than 1.6 seconds. Connecting WDO to MR creates an automatic reset loop: each watchdog fault pulls MR low, generating a 200ms reset pulse that clears the timer. The watchdog is disabled when VCC < reset threshold or when WDI is left floating (internally biased to 1.8V), allowing flexible enable/disable control without external components.

What is the purpose of the LOW LINE output on the MAX807MEUE?

The LOW LINE output on the MAX807MEUE provides a non-maskable interrupt (NMI) signal triggered when VCC drops to 52mV above the reset threshold (i.e., 4.477V for the MAX807MEUE). With ±1.5% accuracy on this offset, it delivers precise early warning - giving the µP time to execute an orderly shutdown routine before reset is asserted. This feature is essential for preserving data integrity in systems without persistent storage.

Can the MAX807MEUE gate chip-enable signals for memory protection?

Yes, the MAX807MEUE includes an integrated chip-enable (CE) gating function. During normal operation, CE IN passes through to CE OUT with only 2ns propagation delay. When reset is asserted, the CE path disables and CE OUT is actively pulled to the higher of VCC or VBATT - preventing spurious memory writes during power transients. This eliminates the need for external logic or glue circuitry to protect SRAM or flash during brownout conditions.