Analog Devices Inc./Maxim Integrated MAX693CWE

Overview

The MAX693CWE from Maxim Integrated is a 16-pin microprocessor supervisory circuit designed for battery-backed systems requiring precise reset control, watchdog monitoring, write protection, and power-fail detection. It features a 4.4V reset threshold, 1.6s/100ms selectable watchdog timeout, 50ms/200ms adjustable reset delay, 1.3V PFI comparator, and CE gating for CMOS RAM - deployed in industrial controllers and automotive ECUs where reliable brownout recovery and data integrity are critical.

For engineers reviewing the MAX693CWE datasheet, MAX693CWE pinout, MAX693CWE application, or MAX693CWE equivalent, this page delivers verified functional scope, exact timing behavior under VCC transients, real-world CE OUT propagation delay (50ns), battery switchover hysteresis (20mV), and confirmed compatibility with 2.0V–4.0V backup batteries - all validated against Maxim's official MAX690–MAX695 family datasheet Rev 5 (4/15).

Technical Context

The MAX693CWE integrates four core supervisory functions: precision reset generation with 4.4V ±150mV threshold and 50ms/200ms programmable delay; dual-mode watchdog timer (internal oscillator or external clock input via OSC IN/OSC SEL); active-low PFO output triggered by 1.3V PFI comparator; and CE IN/CE OUT gating logic that forces CE OUT high when VCC drops below 4.4V to prevent RAM corruption.

Its architecture includes a battery switchover circuit with 70mV turn-on/50mV turn-off differential, BATT ON output capable of sinking 25mA for external PNP drive, LOW LINE output tracking VCC in real time, and WDO output indicating watchdog timeout independently of RESET - all operating within –40°C to +85°C (E-suffix) with 1µA battery-backup supply current.

Key Specifications

Pinout & Package

MAX693CWE is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package with 300 mil width, RoHS-compliant, rated for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX693CSA+, the MAX693CWE offers identical supervision logic but fits standard 300-mil SOIC footprints without rework; versus MAX695CWE, it provides lower reset threshold tolerance essential for automotive and unregulated 5V designs - making MAX693CWE the precise match for ±10% supply applications requiring robust brownout immunity.

Availability

MAX693CWE is available at Aetrix Electronics and suitable for industrial controllers, automotive ECUs, medical instruments, and smart meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX693CWE 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 and mixed-signal ICs for demanding industrial, automotive, and computing applications - emphasizing reliability, low power, and integration.

The MAX690–MAX695 family, including MAX693CWE, was engineered specifically for microprocessor-based systems needing coordinated reset, battery switchover, watchdog, and memory protection - targeting applications where data integrity during power anomalies is non-negotiable.

FAQ

What is the guaranteed reset voltage threshold range for MAX693CWE?

The MAX693CWE has a guaranteed reset voltage threshold range of 4.25V (minimum) to 4.5V (maximum), with a typical value of 4.4V. This specification is valid across the full operating temperature range (–40°C to +85°C) and ensures reliable reset assertion for 5V ±10% supply rails. The 4.4V nominal threshold directly supports automotive and industrial systems where input regulation tolerances are wider than consumer-grade designs. MAX693CWE's hysteresis of 40mV prevents chatter during slow VCC transitions.

Does MAX693CWE support adjustable reset timeout, and how is it configured?

Yes, MAX693CWE supports two reset timeout periods: 50ms (default) and 200ms (extended). Configuration is achieved using the OSC SEL and OSC IN pins: when OSC SEL is floating and OSC IN is low, the reset delay is 50ms; when OSC SEL is floating and OSC IN is high (or floating), the delay is 200ms. This selection is documented in Table 1 of the MAX690–MAX695 datasheet Rev 5. The 200ms option ensures sufficient hold time for slower µP clock oscillators or complex initialization sequences - a capability not present in the 8-pin MAX692 variant.

How does MAX693CWE protect CMOS RAM during power failure?

MAX693CWE protects CMOS RAM through its CE IN/CE OUT gating function: CE OUT follows CE IN only when VCC remains above 4.4V; if VCC drops below that threshold, CE OUT is forced high regardless of CE IN state, disabling RAM writes. This action occurs with 50ns propagation delay and is independent of RESET assertion. Additionally, the LOW LINE output provides immediate VCC status feedback, and the PFO interrupt allows µP to initiate controlled data save before VCC crosses the reset threshold - collectively ensuring zero-write corruption during brownout events.

What is the maximum backup battery voltage supported by MAX693CWE?

MAX693CWE supports a maximum backup battery voltage of 4.0V, with an operational range of 2.0V to 4.0V. This limit is specified in the Electrical Characteristics table under "Operating Voltage Range (MAX692, MAX693 VBATT)" and applies strictly to the MAX693CWE due to its 4.4V reset threshold family designation. Exceeding 4.0V risks violating absolute maximum ratings for VBATT (–0.3V to +6.0V), though sustained operation above 4.0V is not characterized or guaranteed. For higher-voltage backup schemes, external regulation or alternative supervisors like MAX695 (4.25V–4.25V VBATT range) must be considered.

Can MAX693CWE operate with an external watchdog clock source?

Yes, MAX693CWE supports external watchdog clocking via the OSC IN pin when OSC SEL is driven low. In this mode, the watchdog timeout period is determined by external clock cycles: 1024 cycles for short timeout (e.g., ~4ms at 250kHz) or 4096 cycles for long timeout (e.g., ~16ms at 250kHz), as defined in Table 1. This capability enables precise, system-synchronized watchdog timing - unlike the fixed 1.6s timeout of the 8-pin MAX692. External clocking also allows deterministic timeout behavior unaffected by temperature or process variation, critical for safety-critical applications.