Analog Devices Inc./Maxim Integrated MAX820MCSE

Overview

MAX820MCSE from Maxim Integrated is a microprocessor supervisory circuit with dual reset outputs (RESET/RESET), ±2% reset and low-line threshold accuracy, 200ms power-up reset delay, and integrated watchdog timer with programmable timeout via SWT pin. It monitors VCC for brownout detection, provides manual-reset input (MR), chip-enable gating for RAM write protection, and overvoltage warning via OVI/OVO comparator - deployed in industrial controllers and embedded systems requiring reliable power sequencing.

For engineers reviewing the MAX820MCSE datasheet, MAX820MCSE pinout, MAX820MCSE application, or MAX820MCSE equivalent, this page delivers verified functional identity, validated 16-pin SO package mapping, confirmed ±2% threshold accuracy (vs. MAX792's ±3%), exact watchdog timeout behavior (1.6s nominal, capacitor-adjustable), and real-world CE gating timing (10ns max propagation delay) - all directly traceable to Maxim's official 19-0147 Rev. 4 datasheet.

Technical Context

The MAX820MCSE implements independent reset and low-line comparators with factory-trimmed internal thresholds (e.g., 4.37V reset, 4.49V low-line) and supports external resistor programming for custom voltage monitoring points. Its watchdog function uses an RC-timed oscillator referenced to SWT, delivering WDPO pulse (1.7ms min) followed by WDO assertion (70ns later) on timeout.

Chip-enable gating operates via a transmission gate between CE IN and CE OUT, disabled during reset to prevent memory corruption; CE OUT remains low for 15µs after reset assertion if CE IN was low, ensuring write-cycle completion. The device guarantees RESET validity down to VCC = 1V and features 1.30V internal reference buffered at LLIN/REFOUT.

Key Specifications

Pinout & Package

MAX820MCSE is housed in a 16-pin narrow SO (Small Outline) package, 3.9mm width, JEDEC MS-012AC compliant, with gull-wing leads and 0.65mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX792MCSE and TPS3808G33DBVR, the MAX820MCSE uniquely combines ±2% accuracy, dual reset outputs, low-line NMI signaling, and hardware-enforced CE gating - making it irreplaceable in designs requiring deterministic memory write protection and pre-brownout warning.

Availability

MAX820MCSE is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, automotive body control modules, smart energy meters, and critical µP power monitoring applications requiring stable component supply across extended product lifecycles.

Supply support for MAX820MCSE 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, communications, and computing markets.

The MAX820MCSE belongs to Maxim's microprocessor supervisory product line, designed specifically to replace discrete reset generators and watchdog circuits in embedded systems requiring high-accuracy voltage monitoring and hardware-level fault containment.

FAQ

What is the reset threshold voltage for MAX820MCSE?

The MAX820MCSE has a factory-trimmed reset threshold voltage of 4.37V ±2% in internal threshold mode. This value is fixed for the 'M' suffix variant and is guaranteed across the 0°C to +70°C operating temperature range. The threshold is referenced to an internal 1.30V bandgap, and the ±2% accuracy eliminates the need for external calibration in precision power-monitoring applications.

Does MAX820MCSE support external reset threshold programming?

Yes, the MAX820MCSE supports external reset threshold programming via the RESET IN/INT and LLIN/REFOUT pins. When RESET IN/INT is pulled above 600mV, the device enters external mode and disconnects from its internal voltage divider. An external resistor network can then set custom reset and low-line thresholds - for example, 4.4V reset and 4.75V low-line - while retaining the MAX820MCSE's ±2% accuracy for the internal reference used in the divider calculation.

How does the watchdog function work on MAX820MCSE?

The MAX820MCSE watchdog monitors the WDI pin for transitions. If no edge occurs within the timeout period (1.6s nominal with SWT = VCC), WDPO pulses low for ≥1.7ms, followed 70ns later by WDO asserting low. WDPO enables early warning and staged response (e.g., logging), while WDO drives hardware reset. The timeout is adjustable using a capacitor on SWT: 100nF yields ~1.62s at 5V (k=16.2).

What is the purpose of the CE IN and CE OUT pins on MAX820MCSE?

The CE IN and CE OUT pins implement hardware-enforced chip-enable gating on the MAX820MCSE. During normal operation, CE IN passes directly to CE OUT with ≤10ns delay. When reset is asserted, the transmission gate disables, isolating CE IN and pulling CE OUT high. If CE IN is low at reset assertion, CE OUT remains low for 15µs to complete the current memory write cycle - preventing data corruption in CMOS RAM or EEPROM.

Can MAX820MCSE operate with VCC below 2.75V?

Yes, the MAX820MCSE guarantees RESET output validity down to VCC = 1V, though its specified operating range is 2.75V to 5.5V. Below 2.75V, internal comparators and watchdog remain functional until VCC drops near the reset threshold (4.37V for 'M'), at which point RESET asserts and most functions disable. The 1V guarantee ensures clean reset signaling even during deep brownout, supporting fail-safe shutdown sequences.