Analog Devices Inc./Maxim Integrated MAX820LCPE+

Overview

MAX820LCPE+ 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 nominal). It provides active-low/high reset outputs, manual reset input, chip-enable gating, and overvoltage detection - used in embedded controllers and industrial systems requiring reliable power-up/down monitoring.

For engineers reviewing the MAX820LCPE+ datasheet, MAX820LCPE+ pinout, MAX820LCPE+ application, or MAX820LCPE+ equivalent, this page delivers verified functional identity, exact pin roles, real-world timing behavior (e.g., 12µs MR-to-RESET delay), supply-current vs. temperature curves, and validated alternative parts for brownout-critical µP supervision.

Technical Context

The MAX820LCPE+ implements dual-mode voltage monitoring: internal threshold mode (factory-set 4.62V reset, 4.74V low-line) and external programming mode using resistor dividers on RESET IN/INT and LLIN/REFOUT. Its watchdog uses SWT capacitor-based timeout tuning (k = 16.2 @ 5V) and generates both pulse (WDPO) and latched (WDO) fault signals.

It integrates a 10ns max propagation-delay CE transmission gate that disables during reset to protect CMOS RAM write cycles, plus independent overvoltage comparator (OVI/OVO) with 1.30V reference - all operating from 2.75V to 5.5V supply while guaranteeing RESET validity down to VCC = 1V.

Key Specifications

Pinout & Package

MAX820LCPE+ 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 and socketing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX792LCPE+, MAX820LCPE+ delivers tighter threshold accuracy for critical brownout warning; compared with TPS3823MPDBVR, it adds CE gating, dual reset outputs, and WDPO for robust hardware-level fault escalation - essential for safety-critical or data-integrity-sensitive systems.

Availability

MAX820LCPE+ is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic instruments, telecom remote terminal units, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX820LCPE+ 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 - known for high-reliability supervisory, PMIC, and data-converter solutions.

The MAX820LCPE+ belongs to Maxim's µP supervisory product line, engineered specifically for systems demanding deterministic reset timing, multi-level voltage monitoring, and hardware-enforced memory protection during power anomalies.

FAQ

What is the exact reset threshold voltage for MAX820LCPE+?

The MAX820LCPE+ has a nominal reset threshold voltage of 4.62V with ±2% accuracy in internal threshold mode. This value is factory-trimmed and specified at TA = +25°C with VCC falling. The L-suffix denotes the 4.62V variant, and the ±2% tolerance ensures consistent brownout detection across temperature and unit-to-unit variation - a key differentiator from the MAX792 series.

Does MAX820LCPE+ support external reset threshold programming?

Yes, MAX820LCPE+ supports external programming mode. By pulling RESET IN/INT above 600mV and applying external resistor dividers to LLIN/REFOUT and RESET IN/INT, users can set custom low-line and reset thresholds independently. The MAX820LCPE+ maintains its ±2% accuracy advantage even in external mode when using precision resistors, unlike the MAX792 which specifies only internal-mode accuracy.

How does the watchdog timeout work on MAX820LCPE+?

The MAX820LCPE+ watchdog timeout defaults to 1.6s when SWT is tied to VCC. To adjust it, connect a capacitor from SWT to GND: timeout = k × C_SWT, where k = 16.2 for VCC = 5V and k = 27 for VCC = 3V. The capacitor must exceed 4.7nF for valid operation. WDPO pulses first, followed 70ns later by WDO - enabling two-fault shutdown via external flip-flop, a capability not found in basic watchdog ICs.

What is the purpose of the CE IN and CE OUT pins on MAX820LCPE+?

The CE IN and CE OUT pins implement a transmission gate that blocks chip-enable signals during reset. When reset is active, CE IN goes high-impedance and CE OUT is pulled high, preventing spurious memory writes during brownout. If CE IN is low when reset asserts, CE OUT stays low for 15µs to complete the ongoing write cycle - a hardware-level safeguard against data corruption in CMOS RAM or EEPROM that requires no firmware intervention.

Can MAX820LCPE+ operate down to 1V supply voltage?

Yes, MAX820LCPE+ guarantees valid RESET output operation down to VCC = 1V, a critical feature for battery-depleted or ultra-low-voltage systems. While internal comparators cease functioning below ~2.75V, the RESET output stage remains functional with reduced drive strength. An external 10kΩ pull-down on RESET ensures logic-low validity even at VCC = 0V, making MAX820LCPE+ uniquely suited for fail-safe shutdown in energy-harvesting or backup-power applications.