Analog Devices Inc./Maxim Integrated MAX699CWE+

Overview

MAX699CWE+ from Maxim Integrated is a low-cost, single-chip power-on reset and watchdog controller for +5V microprocessor systems. It delivers a guaranteed 140ms RESET pulse on power-up, brownout (trip at 4.4V), and power-down, features an enabled watchdog timer with 1s timeout, and operates from 3.0V to 5.5V supply. It is used in embedded controllers requiring reliable power sequencing and processor activity monitoring.

For engineers reviewing the MAX699CWE+ datasheet, MAX699CWE+ pinout, MAX699CWE+ application, or MAX699CWE+ equivalent, key selection criteria include its 4.65V reset threshold with 40mV hysteresis, open-drain RESET output (0.4V @ 1.6mA), WDO output capability, and compatibility with 16-pin wide SO package layouts.

Technical Context

The MAX699CWE+ integrates a precision voltage monitor and monostable reset timer in a single IC, eliminating external RC timing components. Its internal comparator detects VCC falling below 4.4V (assert) and rising above 4.65V (deassert), with fixed 40mV hysteresis to prevent chatter during slow-rising supplies.

The watchdog circuit monitors the WDI input: if no transition occurs within 1 second, it forces both RESET and WDO low. WDI is a three-level input (logic-low ≤0.8V, logic-high ≥3.8V), and leaving it unconnected disables the watchdog function entirely.

Key Specifications

Pinout & Package

MAX699CWE+ is housed in a 16-lead, 0.3-inch wide SO (small outline) package with exposed pad not present; RoHS-compliant lead-free finish indicated by '+' suffix.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power-on reset and watchdog controller applications.

Compared with MAX699CWE+, MAX698CWE+ omits watchdog supervision entirely, while TPS3808G33DBVR targets lower-voltage domains and requires external components to achieve equivalent runtime monitoring - making MAX699CWE+ the sole solution offering integrated +5V reset + watchdog in a single 16-pin SO package.

Availability

MAX699CWE+ is available at Aetrix Electronics and suitable for industrial controllers, embedded data loggers, and medical diagnostic instruments requiring stable component supply and long-term design continuity.

Supply support for MAX699CWE+ 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, computing, and communications applications.

The MAX698/MAX699 product line delivers integrated power-on reset and watchdog functionality specifically for +5V microprocessor systems, targeting cost-sensitive, high-reliability embedded control applications.

FAQ

What is the reset threshold voltage for MAX699CWE+?

The MAX699CWE+ asserts RESET when VCC falls below 4.4V and deasserts it when VCC rises above 4.65V. This 40mV hysteresis prevents oscillation during marginal supply conditions. These thresholds are factory-trimmed and guaranteed across the 0°C to +70°C operating range, ensuring consistent behavior without external calibration. The MAX699CWE+ uses these fixed thresholds to provide deterministic reset timing in +5V systems.

Does MAX699CWE+ require external components to function?

No, the MAX699CWE+ operates fully autonomously with zero external components. Its internal voltage reference, comparator, reset timer, and watchdog circuitry eliminate the need for external resistors, capacitors, or timing networks. This simplifies PCB layout, reduces BOM cost, and improves reliability - a core design goal confirmed in the device's "minimum component count" feature and typical operating circuit diagrams. The MAX699CWE+ achieves this while maintaining guaranteed 140ms reset pulse width and 1s watchdog timeout.

How is the watchdog function enabled or disabled on MAX699CWE+?

The watchdog function in MAX699CWE+ is enabled by driving the WDI pin (pin 11) with a regular logic transition at least once every 1 second. If WDI remains static (high or low) beyond that interval, RESET and WDO go low. To disable the watchdog, leave WDI unconnected - the internal circuitry interprets this as a disable condition. This behavior is explicitly documented in the Pin Description and Electrical Characteristics tables for MAX699CWE+. No configuration register or external signal is required.

What are the electrical characteristics of the RESET outputs on MAX699CWE+?

MAX699CWE+ provides two open-drain RESET outputs: pin 15 (active-low) and pin 16 (active-high). Both sink 1.6mA with ≤0.4V drop and source 1μA with ≥3.5V high-level output under specified conditions. These drive strengths ensure compatibility with standard CMOS/TTL inputs and allow direct connection to microcontroller reset pins or pull-up networks. The dual-output architecture gives designers flexibility without adding level-shifting circuitry - a verified capability in the MAX699CWE+ datasheet's Electrical Characteristics table.

Is MAX699CWE+ pin-compatible with MAX698CWE+?

MAX699CWE+ and MAX698CWE+ share the same 16-pin wide SO package footprint and power/ground pin assignments (pins 1,2,3,4,9), but differ functionally: MAX699CWE+ adds WDI (pin 11) and WDO (pin 14), and provides dual RESET outputs (pins 15 and 16), whereas MAX698CWE+ has only one RESET (pin 15) and no WDI/WDO. Therefore, they are not drop-in replacements - PCBs designed for MAX699CWE+ will have unused pins when populated with MAX698CWE+, and vice versa. This mapping is confirmed in the Pin Configuration and Pin Description sections of the MAX699CWE+ datasheet.