Analog Devices Inc./Maxim Integrated MAX823LEXK+

Overview

MAX823LEXK+ from Maxim Integrated is a 5-pin SC70-packaged microprocessor supervisory circuit with active-low reset, watchdog timer, and manual reset input. It monitors +4.63V power supplies, delivers 140ms minimum power-on reset timeout, guarantees RESET validity down to VCC = 1V, and provides 1.6s watchdog timeout - used in embedded controllers and critical µP monitoring systems.

For engineers reviewing the MAX823LEXK+ datasheet, MAX823LEXK+ pinout, MAX823LEXK+ application, or MAX823LEXK+ equivalent, key selection factors include reset threshold accuracy (±1.5% over temperature), ultra-low 2µA supply current (SC70), transient immunity on VCC, and compatibility with bidirectional µP reset pins requiring ≤400µA pullup current.

Technical Context

The MAX823LEXK+ integrates a precision voltage comparator with 4.63V reset threshold, a 1.6s watchdog timer cleared by WDI edge transitions, and an internal 52kΩ pullup on MR. Its reset generator asserts active-low RESET for ≥140ms after VCC rise, brownout recovery, or MR deassertion.

It operates from -40°C to +85°C, supports VCC down to 1V with guaranteed RESET state, and features 5mV reset hysteresis and 40ppm/°C temperature coefficient - enabling stable operation across industrial temperature ranges without external components.

Key Specifications

Pinout & Package

MAX823LEXK+ uses a 5-pin SC70-5 package (drawing 21-0076E), measuring 2.0mm × 2.1mm × 0.95mm, RoHS-compliant and lead-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX823LEXK+, MAX823TEUK+ offers wider temperature range and different threshold but requires PCB layout change due to SOT23-5; TPS3808G33DBVR reduces functionality (no watchdog/MR) and changes reset behavior (open-drain), limiting direct substitution in safety-critical or feature-rich designs.

Availability

MAX823LEXK+ is available at Aetrix Electronics and suitable for embedded controllers, automotive ECUs, and portable medical devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX823LEXK+ 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, mixed-signal, and power management ICs for industrial, automotive, and computing applications.

The MAX823 family delivers integrated µP supervision with reset, watchdog, and manual reset in ultra-small packages - engineered for space-constrained, high-reliability embedded systems demanding low power and robust transient immunity.

FAQ

What is the reset threshold voltage of the MAX823LEXK+?

The MAX823LEXK+ has a factory-trimmed reset threshold of 4.63V with ±1.5% tolerance over -40°C to +85°C. This value is fixed and non-adjustable, optimized for monitoring +4.63V power rails in industrial and automotive applications. The threshold remains stable across temperature due to 40ppm/°C coefficient, and the device guarantees RESET assertion until VCC rises above this level.

Does the MAX823LEXK+ include a watchdog timer, and how is it configured?

Yes, the MAX823LEXK+ includes a watchdog timer with a nominal timeout of 1.6s (1.12–2.40s over temperature). It is edge-triggered: any rising or falling edge on the WDI pin clears the timer. Leaving WDI unconnected disables the watchdog function. The timer does not require external components and is fully integrated - no configuration registers or external clock needed. This makes MAX823LEXK+ suitable for simple, reliable firmware hang detection.

What package type and dimensions does the MAX823LEXK+ use?

The MAX823LEXK+ uses the SC70-5 package (drawing 21-0076E), measuring 2.0mm × 2.1mm × 0.95mm with 0.65mm pin pitch. It is RoHS-compliant and lead-free, marked "AAL" on top. This ultra-compact 5-pin surface-mount package enables high-density PCB layouts in space-constrained applications such as portable instrumentation and automotive sensors where the MAX823LEXK+ is commonly deployed.

Can the MAX823LEXK+ operate with supply voltages below 4.63V?

Yes - the MAX823LEXK+ operates with VCC from +4.5V to +5.5V, and its RESET output remains valid down to VCC = 1V. While the reset comparator triggers at 4.63V, the internal circuitry continues functioning at lower VCC levels to ensure correct reset state during brownout. This capability allows the MAX823LEXK+ to support backup power switchover and maintain system integrity even as main supply collapses.

Is there an internal pullup resistor on the MR pin of the MAX823LEXK+?

Yes, the MAX823LEXK+ includes a factory-trimmed 52kΩ internal pullup resistor on the MR pin. This eliminates the need for an external resistor and allows direct connection of a momentary switch between MR and GND. When unused, MR may be left floating or tied to VCC. The internal pullup ensures defined logic-high state and enables clean, debounced manual reset activation without additional components - a key design simplification in the MAX823LEXK+ implementation.