Analog Devices Inc./Maxim Integrated MAX807LCWE+

Overview

The MAX807LCWE+ from Maxim Integrated is a precision microprocessor supervisory circuit designed for +5V systems, providing active-low and active-high reset outputs, manual reset input, watchdog timer with 1.6s timeout, two-stage power-fail warning (PFI/PFO), low-line comparator (52mV above reset threshold), battery switchover (250mA VCC mode / 20mA battery mode), and chip-enable gating with 2ns propagation delay. It guarantees RESET validity down to VCC = 1V and supports portable, industrial, and critical embedded systems requiring stable power monitoring.

For engineers reviewing the MAX807LCWE+ datasheet, MAX807LCWE+ pinout, MAX807LCWE+ application, or MAX807LCWE+ equivalent, this page delivers verified functional specifications, validated pin roles, confirmed reset accuracy (±1.5%), real-world timing behavior (200ms reset timeout), and direct alternative part comparisons - all grounded in Maxim's official documentation and electrical characteristics.

Technical Context

The MAX807LCWE+ integrates seven independent monitoring and control functions in a single BiCMOS IC: a ±1.5% accurate 4.675V reset comparator, a dedicated low-line comparator with 52mV offset and 13mV hysteresis, a 1.6s watchdog timer with WDI/WDO interface, a power-fail comparator (2.265V threshold), battery switchover logic with BATT ON flag, CE signal gating with sub-8ns propagation, and dual reset outputs (RESET/RESET) with asymmetric drive strength.

Its architecture separates supply-path control (VCC→OUT vs. BATT→OUT switching), logic-level supervision (MR-triggered and voltage-triggered reset assertion), and system-level fault response (WDO-to-MR reset chaining, LOW LINE NMI generation). All comparators feature internal reference trimming, and the chip-enable gate operates in enabled/disabled modes synchronized to reset state.

Key Specifications

Pinout & Package

MAX807LCWE+ is housed in a 16-pin wide SOIC (SO) package with 300 mil body width and standard 0.050" lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809SCPA+ and TPS3808G18DBVR, the MAX807LCWE+ uniquely integrates battery switchover, dual reset outputs, watchdog timer, and CE gating - making it the only option among the three that fully supports complex +5V systems requiring data retention, orderly shutdown, and memory protection during power faults.

Availability

MAX807LCWE+ is available at Aetrix Electronics and suitable for industrial automation, medical handhelds, automotive infotainment, and smart energy metering applications requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance.

Supply support for MAX807LCWE+ 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 demanding industrial, automotive, and communications applications.

The MAX807L/M/N family was engineered specifically for +5V microprocessor systems needing precision reset supervision, battery-backed memory retention, and proactive power-fail response - addressing reliability gaps in legacy supervisors through ±1.5% threshold accuracy and integrated CE gating.

FAQ

What is the exact reset threshold voltage of the MAX807LCWE+?

The MAX807LCWE+ has a nominal reset threshold of 4.675V with ±1.5% accuracy over temperature (-40°C to +85°C). This value is laser-trimmed during production and specified in the Electrical Characteristics table under VRST parameter for the 'L' variant. The threshold remains stable across VCC supply variations and ensures consistent reset assertion before downstream +5V logic enters undefined states.

Does the MAX807LCWE+ support battery switchover, and what are the current limits?

Yes, the MAX807LCWE+ supports automatic battery switchover: when VCC falls below the reset threshold and VBATT exceeds 2.0V, OUT disconnects from VCC and connects to BATT. In VCC mode, it delivers up to 250mA; in battery-backup mode, it sustains 20mA continuous output. The BATT ON output signals the switchover state and can drive external PMOS/PNP switches for higher current loads.

How does the watchdog timer in the MAX807LCWE+ operate, and what is its timeout period?

The MAX807LCWE+ watchdog timer asserts WDO low if the WDI input remains static (high or low) for longer than 1.6s (typical). A rising or falling edge on WDI clears the timer and returns WDO high, provided RESET is deasserted. When WDO is connected to MR, each timeout generates a 200ms reset pulse - enabling autonomous recovery from software hangs without host processor involvement.

Can the MAX807LCWE+ monitor power supplies other than +5V?

Yes, the MAX807LCWE+ supports multi-supply monitoring: the PFI input accepts external voltage dividers to set custom power-fail thresholds (e.g., for 3.3V or 12V rails), while the 2.275V threshold detector (PFI/PFO) and LOW LINE comparator (52mV above reset) provide flexible warning points. The BATT OK comparator also verifies backup battery health independently of VCC level.

What is the purpose of the CE IN and CE OUT pins on the MAX807LCWE+?

The CE IN and CE OUT pins implement chip-enable signal gating: during normal operation, CE IN passes directly to CE OUT with ≤8ns propagation delay; during reset, CE OUT is actively pulled to the higher of VCC or VBATT, blocking spurious memory accesses. This prevents data corruption in CMOS RAM during power transitions and eliminates need for external gating logic.