Analog Devices Inc./Maxim Integrated MAX807NCPE+

Overview

MAX807NCPE+ from Maxim Integrated is a full-featured microprocessor supervisory circuit designed for power monitoring, battery switchover, and watchdog protection in 5V µP systems. It provides active-low and active-high RESET outputs, manual reset input (MR), two-stage power-fail warning (PFI/PFO), low-line comparator (LOW LINE), BATT OK status flag, and independent watchdog timer with 1.6s timeout. Its ±1.5% reset threshold accuracy (4.575V), 200ms reset timeout, and guaranteed RESET validity down to VCC = 1V make it suitable for portable/battery-powered equipment requiring robust brownout immunity.

For engineers reviewing the MAX807NCPE+ datasheet, MAX807NCPE+ pinout, MAX807NCPE+ application, or MAX807NCPE+ equivalent, this page delivers verified functional identity, validated 16-pin PDIP package mapping, confirmed dual-reset architecture, battery-switchover behavior under VCC collapse, and real-world timing constraints including 2ns CE gate propagation delay and 28µs CE disable latency after reset assertion.

Technical Context

The MAX807NCPE+ integrates seven distinct supervisory functions within a single BiCMOS IC: precision reset detection (±1.5% at 4.575V), low-line comparator (52mV above reset threshold, ±13mV hysteresis), power-fail comparator (2.265V threshold), manual reset with 200ms debounce, independent watchdog timer (1.6s timeout), chip-enable gating (2ns propagation, 75Ω series resistance), and bidirectional backup-battery switchover (250mA VCC mode / 20mA battery mode).

Its architecture separates critical paths: RESET/RESET outputs use strong-pulldown/weak-pullup and full CMOS drive respectively; LOW LINE triggers NMI on falling VCC; BATT ON controls external PNP/PMOS switches for high-current switchover; and WDO connects to MR to convert watchdog faults into system resets - all coordinated by an internal state machine synchronized to VCC transitions.

Key Specifications

Pinout & Package

MAX807NCPE+ is supplied in a 16-pin plastic DIP (Dual In-line Package) with 0.300" wide body and 0.100" lead pitch, compatible with standard through-hole PCB assembly and socketing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX807NCPE+, MAX809SCPA+ omits 5 of 7 core functions (watchdog, CE gating, LOW LINE, BATT OK, battery switchover), while TPS3808G18DBVR targets different voltage domains and lacks the precise 52mV low-line offset and dual-supply switchover essential for 5V industrial backup systems.

Availability

MAX807NCPE+ is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC controllers, point-of-sale terminals, and smart energy meters requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for MAX807NCPE+ 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, communications, and computing markets.

The MAX807 family was designed specifically for µP-based systems needing integrated power monitoring, battery backup control, and watchdog supervision in a single 16-pin package - targeting reliability-critical embedded applications where discrete solutions increase BOM count and failure risk.

FAQ

What is the exact reset threshold voltage for MAX807NCPE+ and how tightly is it specified?

The MAX807NCPE+ has a nominal reset threshold of 4.575V with ±1.5% initial accuracy over temperature, meaning the actual threshold falls between 4.500V and 4.650V across its operating range. This specification is guaranteed by production testing and is tighter than legacy supervisors (e.g., ±2.5%), ensuring consistent µP reset behavior across voltage and temperature variations in 5V systems.

Does MAX807NCPE+ support automatic switchover between main supply and backup battery, and what are the current limits?

Yes, MAX807NCPE+ automatically switches the OUT pin from VCC to BATT when VCC falls below the reset threshold (4.575V), provided VBATT >2.0V. It delivers up to 250mA from VCC in normal operation and up to 20mA from battery in backup mode. For higher backup currents, the BATT ON output drives external PNP/PMOS switches - a capability not found in simpler supervisors like the MAX809.

How does the low-line comparator in MAX807NCPE+ differ from the main reset comparator, and why is that useful?

The MAX807NCPE+ low-line comparator triggers at VCC = VRST + 52mV (e.g., ~4.627V for the N version), 52mV above the reset threshold, with ±13mV hysteresis. This provides a deterministic early warning before reset assertion, allowing µP firmware to execute an orderly shutdown - unlike the reset comparator which halts execution. This two-stage alert is critical for data integrity in systems like smart meters and PLCs.

Can MAX807NCPE+ be used to protect CMOS RAM writes during power failure, and how is this implemented?

Yes, MAX807NCPE+ protects CMOS RAM via its chip-enable (CE) gating function: CE IN passes through to CE OUT during normal operation but is disabled (CE OUT pulled high) when RESET is asserted. With 2ns propagation delay and automatic disable within 28µs of reset assertion, it prevents spurious writes during brownout recovery - a feature absent in basic reset-only ICs and essential for reliable nonvolatile data storage.

What watchdog timeout period does MAX807NCPE+ provide, and how is it reset?

MAX807NCPE+ provides a fixed 1.6s typical watchdog timeout period. The internal timer resets on any edge (low-to-high or high-to-low) at the WDI pin while RESET is deasserted. If WDI remains static beyond 1.6s, WDO goes low - and when wired to MR, this generates a 200ms reset pulse. The watchdog is automatically disabled when VCC falls below the reset threshold or when WDI is left floating (internally biased to 1.8V).