Analog Devices Inc./Maxim Integrated MAX801MCSA+

Overview

MAX801MCSA+ from Maxim Integrated is a precision +5V microprocessor supervisory IC with battery switchover, low-line warning, and watchdog timer functionality. It provides active-low and active-high reset outputs (RESET/RESET), 4.425V ±1.5% reset threshold, 200ms reset timeout, and operates across –40°C to +85°C in 8-pin SO package. It is used in portable/battery-powered equipment to ensure reliable µP startup, orderly shutdown, and RAM data retention during brownout.

For engineers reviewing the MAX801MCSA+ datasheet, MAX801MCSA+ pinout, MAX801MCSA+ application, or MAX801MCSA+ equivalent, this page delivers verified electrical parameters, functional timing behavior, battery-backup mode operation, watchdog timeout behavior, and real-world design implications for critical µP power monitoring systems.

Technical Context

The MAX801MCSA+ integrates three independent comparators - reset (4.425V threshold), low-line (4.477V rising threshold, 52mV above reset), and battery switchover - plus a 1.6s watchdog timer with WDI transition detection and internal state machine. Its BiCMOS process enables ±1.5% reset accuracy and 1µA standby current in battery-backup mode.

It implements dual-power-path switching: VCC-to-OUT (250mA, 1.2Ω typical on-resistance) and BATT-to-OUT (20mA, 12Ω typical), with guaranteed RESET validity down to VCC = 1V. The RESET output uses strong-pull-down/weak-pull-up topology; RESET is full CMOS, enabling direct µP interface without external pull-ups.

Key Specifications

Pinout & Package

MAX801MCSA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant with lead-free finish (+ suffix). Pin 1 is marked with dot or bevel; pin numbering follows standard SO convention (counterclockwise from mark).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX801MCSA+, MAX809MUS+T sacrifices all advanced supervision features for footprint and cost reduction, while TPS3808G33DBVR trades battery switchover and low-line warning for programmable delay in lower-voltage domains - neither matches the integrated +5V supervisory, watchdog, and backup capability of MAX801MCSA+.

Availability

MAX801MCSA+ is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial PLC controllers, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX801MCSA+ 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.

The MAX801 belongs to Maxim's µP supervisory product line, designed specifically for robust +5V system power monitoring, battery-backed RAM protection, and fail-safe firmware execution in mission-critical embedded applications.

FAQ

What is the exact reset threshold voltage of the MAX801MCSA+?

The MAX801MCSA+ has a nominal reset threshold of 4.425V with ±1.5% accuracy over temperature and supply variation. This value is confirmed in the Electrical Characteristics table under "VRST Reset Threshold" for the "M" suffix variant, and is validated across the –40°C to +85°C operating range. The MAX801MCSA+ does not use adjustable or external resistor-set thresholds - the 4.425V is factory-trimmed and fixed.

Does the MAX801MCSA+ support battery backup for CMOS RAM?

Yes, the MAX801MCSA+ supports battery backup for CMOS RAM via its dedicated BATT and OUT pins. When VCC falls below both the reset threshold (4.425V) and VBATT, the internal PMOS switch connects BATT to OUT, supplying up to 20mA at ≤12Ω on-resistance. This function is fully operational in the MAX801MCSA+ and is documented in the Battery-Backup Mode section and Table 1 of the datasheet.

Is the watchdog timer on the MAX801MCSA+ enabled by default?

No, the watchdog timer on the MAX801MCSA+ is disabled by default when the WDI pin is left unconnected. An internal voltage divider pulls WDI to ~1.8V, which disables the watchdog function. To enable it, the host µP must actively toggle WDI with edges spaced less than 1.6s apart. This behavior is explicitly stated in Note 4 and the Detailed Description section of the MAX801MCSA+ datasheet.

Can the MAX801MCSA+ generate both active-low and active-high reset signals simultaneously?

Yes, the MAX801MCSA+ provides simultaneous RESET (active-low) and RESET (active-high) outputs. RESET uses a strong-pull-down/weak-pull-up structure suitable for wire-OR configurations, while RESET is a full CMOS buffer capable of sourcing/sinking 5mA. Both outputs are asserted/deasserted in strict complementarity, with identical 200ms timeout timing - confirmed in the Pin Description and Detailed Description sections.

What is the maximum output current capability of the OUT pin on the MAX801MCSA+?

The OUT pin of the MAX801MCSA+ supports up to 250mA when sourced from VCC (with typical VCC-to-OUT on-resistance of 1.2Ω), and up to 20mA when sourced from BATT (with typical BATT-to-OUT on-resistance of 12Ω). These values are specified in the Absolute Maximum Ratings and Electrical Characteristics tables, and apply across the full operating temperature range of –40°C to +85°C.