Analog Devices Inc./Maxim Integrated MAX807LCWE+T

Overview

The MAX807LCWE+T 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 ensures reliable µP startup and brownout protection in portable and industrial embedded systems.

For engineers reviewing the MAX807LCWE+T datasheet, MAX807LCWE+T pinout, MAX807LCWE+T application, or MAX807LCWE+T equivalent, this page delivers verified functional identity, confirmed ±1.5% reset accuracy (4.675V threshold), validated 16-pin TSSOP package mapping, full terminal roles, and two rigorously cross-checked alternative parts for critical power-monitoring designs.

Technical Context

The MAX807LCWE+T integrates seven independent monitoring functions: a precision reset comparator with hysteresis, a low-line comparator referenced 52mV above the reset threshold, a power-fail comparator (2.265V threshold), a watchdog timer with transition-detection logic, battery-OK status flag, manual-reset input with internal 50–200µA pullup, and BiCMOS-based CE signal gating. All comparators feature CMOS logic outputs swinging rail-to-rail between VCC and GND.

Its dual-supply architecture supports seamless switchover between VCC and VBATT (2.0V–6V), with guaranteed RESET validity down to VCC = 1V and BATT OK assertion at VBATT ≥ 2.265V. The device operates across 0°C to +70°C (C-grade) and draws only 70µA typical supply current in normal mode and 1µA in battery-standby mode.

Key Specifications

Pinout & Package

MAX807LCWE+T is housed in a 16-pin TSSOP package (4.4mm × 5.0mm, 0.65mm pitch), RoHS-compliant and moisture-sensitive level 1 (MSL1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX807LCWE+T, MAX810LUR+T sacrifices all advanced supervision features for minimal footprint, while TPS3808G33DBVR targets low-voltage domains and omits battery management entirely - neither replicates the integrated 5V power-fail warning, watchdog-loop reset, or dual-supply RAM protection of the MAX807LCWE+T.

Availability

MAX807LCWE+T is available at Aetrix Electronics and suitable for industrial PLC controllers, medical patient monitors, automotive infotainment head units, and point-of-sale terminals requiring stable component supply with guaranteed long-term manufacturability and consistent parametric performance.

Supply support for MAX807LCWE+T 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 applications.

The MAX807L/M/N family was engineered specifically for robust +5V microprocessor supervision in battery-critical and safety-sensitive systems, integrating reset, watchdog, power-fail warning, and battery switchover into a single BiCMOS die with ±1.5% voltage accuracy.

FAQ

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

The MAX807LCWE+T has a guaranteed reset threshold of 4.675V with ±1.5% accuracy across temperature and supply voltage. This value is factory-trimmed and specified in the Electrical Characteristics table under VRST for the 'L' variant. It ensures deterministic reset assertion when VCC falls below this precise level, critical for stable operation in +5V systems where marginal voltage operation must be avoided.

Does the MAX807LCWE+T support battery backup for CMOS RAM, and what are its current limits?

Yes, the MAX807LCWE+T provides fully integrated battery backup switchover for CMOS RAM. When VCC drops below the switchover threshold, OUT automatically connects to BATT. In battery-backup mode, it delivers up to 20mA at ≤12Ω on-resistance (VBATT = 2.8V), sufficient for most low-power SRAM and RTC circuits. The BATT OK flag confirms battery readiness before switchover occurs.

How does the watchdog function work on the MAX807LCWE+T, and can it trigger a system reset autonomously?

The MAX807LCWE+T watchdog monitors the WDI input and asserts WDO low if no edge occurs within 1.6s. By connecting WDO to MR, the device creates an autonomous reset loop: WDO low pulls MR low, initiating a 200ms reset pulse. This requires no firmware involvement and ensures recovery from µP lockups. WDI left unconnected disables the watchdog and holds WDO high.

What is the purpose of the LOW LINE output, and how does it differ from the RESET output?

The LOW LINE output is an early-warning comparator that asserts low when VCC falls to 52mV above the reset threshold (i.e., ~4.727V for MAX807LCWE+T). Unlike RESET, which halts the system, LOW LINE generates a nonmaskable interrupt (NMI) to initiate graceful software shutdown - providing critical time to save state before the hard reset occurs 200ms later.

Can the MAX807LCWE+T monitor power supplies other than +5V, and how is this implemented?

Yes, the MAX807LCWE+T can monitor non-5V supplies using its dedicated PFI input. By configuring a resistor divider between the target supply and PFI, the 2.265V internal reference sets the trip point. For example, a 12V supply can be scaled to 2.265V using R1/R2 = 4.3:1. PFO then asserts low on decay, enabling NMI-driven shutdown - independent of the main VCC rail.