Analog Devices Inc./Maxim Integrated MAX820MCPE+

Overview

MAX820MCPE+ from Maxim Integrated is a microprocessor supervisory circuit with ±2% reset and low-line threshold accuracy, 200ms reset timeout, and integrated watchdog timer with programmable timeout (1.6s default). It provides active-low/high reset outputs, manual-reset input, chip-enable gating, and overvoltage detection - used in industrial controllers and embedded systems requiring reliable power-up/down monitoring.

For engineers reviewing the MAX820MCPE+ datasheet, MAX820MCPE+ pinout, MAX820MCPE+ application, or MAX820MCPE+ equivalent, this page delivers verified functional identity, exact pin roles, confirmed timing parameters (200ms reset delay, 70ns WDPO-to-WDO delay), real-world memory protection use cases, and two validated alternative parts with documented threshold and temperature-range differences.

Technical Context

The MAX820MCPE+ implements dual-voltage monitoring via independent reset and low-line comparators, both referenced to a precision 1.30V internal bandgap. Its reset comparator guarantees valid output down to VCC = 1V, while the low-line comparator asserts 120mV above the reset threshold with 15mV hysteresis. The device supports both internal factory-set thresholds and external resistor-programmable thresholds via the RESET IN/INT and LLIN/REFOUT pins.

It integrates a watchdog timer with pulse output (WDPO) and fault output (WDO), where WDPO precedes WDO by 70ns and pulses for 1.7ms to enable hardware shutdown sequencing. Chip-enable gating features 10ns max propagation delay and write-cycle completion hold (15µs CE OUT low after reset assertion when CE IN is low), ensuring safe CMOS RAM write termination during brownout.

Key Specifications

Pinout & Package

MAX820MCPE+ is housed in a 16-pin plastic DIP (Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch, compatible with standard PCB layouts for legacy and industrial control designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX792MCPE+, the MAX820MCPE+ delivers higher threshold accuracy for stable operation in marginal 3.3V supplies, while TPS3823MPWPT trades multi-function capability for extended temperature support and simplified architecture - making each optimal for distinct reliability and environmental requirements.

Availability

MAX820MCPE+ is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic devices, telecom base station controllers, and automotive infotainment head units requiring stable component supply with long-term manufacturability and traceable sourcing.

Supply support for MAX820MCPE+ 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 in industrial, medical, and communications systems.

The MAX820MCPE+ belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power-monitoring, watchdog supervision, and memory protection in mission-critical embedded systems operating across commercial temperature ranges.

FAQ

What is the guaranteed minimum VCC level at which MAX820MCPE+ maintains valid RESET output?

The MAX820MCPE+ guarantees valid RESET output down to VCC = 1V, as confirmed in the Electrical Characteristics table under "RESET Output Voltage" with ISINK = 50µA and VCC falling. This ensures reliable reset assertion even during deep brownout conditions where other supervisors may fail. The MAX820MCPE+ achieves this via optimized output stage design and internal biasing that remains functional below 2V. External 10kΩ pull-down on RESET extends validity to GND.

How does the ±2% reset threshold accuracy of MAX820MCPE+ differ from the MAX792MCPE+ in practical design?

The ±2% reset threshold accuracy of MAX820MCPE+ reduces worst-case voltage margin uncertainty by 1% compared to MAX792MCPE+'s ±3%, directly enabling tighter design margins on 3.3V rails (e.g., 3.3V ±5% LDO). For a 2.91V nominal threshold, MAX820MCPE+ guarantees 2.85V–2.97V trip range vs. 2.82V–3.00V for MAX792MCPE+. This minimizes false resets in noisy environments and improves consistency across temperature and unit-to-unit variation - critical for medical and industrial certification.

Can MAX820MCPE+ be used with a 3.3V supply, and what are the key timing implications?

Yes, MAX820MCPE+ operates fully across 2.75V to 5.5V, including 3.3V nominal supplies. At VCC = 3.3V, watchdog timeout scales to k = 16.2 × C (nF) ms, and CE propagation delay remains ≤10ns. Reset timeout stays at 200ms typical, and LOW LINE asserts 120mV above reset threshold (e.g., 3.03V for 2.91V reset). Supply current is 70µA typical at 3.3V/25°C per Electrical Characteristics - confirming stable operation without derating.

What is the functional difference between WDPO and WDO outputs on MAX820MCPE+?

WDPO (Watchdog Pulse Output) is a 1.7ms low-going pulse that precedes WDO assertion by 70ns, serving as an advance warning of impending watchdog fault. WDO (Watchdog Output) goes low and stays low until the next WDI transition, acting as the primary fault signal. WDPO enables hardware-level response sequencing - e.g., clocking a D flip-flop to latch shutdown on two consecutive faults - while WDO provides direct reset or interrupt signaling. Both are active-low and open-drain compatible.

Does MAX820MCPE+ support external programming of reset and low-line thresholds, and how is it implemented?

Yes, MAX820MCPE+ supports external programming via the RESET IN/INT and LLIN/REFOUT pins. Pulling RESET IN/INT ≥600mV disconnects internal dividers and connects comparators to external resistive dividers. Equations in the datasheet define R1–R3 values based on desired VRESET and VLOW LINE thresholds and chosen divider current (e.g., 5µA). This allows precise setting of thresholds like 4.4V reset and 4.75V low-line - essential for custom power-rail monitoring not covered by factory presets.