Analog Devices Inc./Maxim Integrated MAX697EWE+T

Overview

The MAX697EWE+T from Maxim Integrated is a microprocessor supervisory circuit designed for power-supply monitoring and CMOS RAM write protection in industrial and embedded systems. It provides adjustable low-line reset (1.25V–1.35V), watchdog timeout (100ms/1.6s), 50ms reset pulse width, 1.3V power-fail detection, and CE IN/CE OUT gating logic - all while consuming ≤300µA supply current at full temperature range.

For engineers reviewing the MAX697EWE+T datasheet, MAX697EWE+T pinout, MAX697EWE+T application, or MAX697EWE+T equivalent, this device serves as a low-power, precision voltage-monitoring and memory-protection solution for systems requiring reliable power-fail warning, watchdog supervision, and chip-enable control without battery backup switching.

Technical Context

The MAX697EWE+T integrates six core functions: a precision 1.3V comparator for LLIN monitoring, a dual-mode watchdog timer (internal oscillator or external clock/capacitor), a dedicated 1.3V PFI comparator with PFO output, CE IN/CE OUT gating logic for RAM write protection, RESET/RESET outputs with 50ms monostable timing, and OSC SEL-controlled timing configuration. Its architecture separates power-fail detection from low-line reset to enable staged system response.

All timing functions are derived from either an internal 10.24kHz oscillator (when OSC SEL is high/floating) or externally configured sources (capacitor on OSC IN or clock signal), with distinct timeout behavior immediately after reset versus steady-state operation. The CE gating path operates only when LLIN > 1.3V, ensuring write disable during brownout conditions.

Key Specifications

Pinout & Package

MAX697EWE+T is housed in a 16-pin Wide SO (SOIC-W) package, RoHS-compliant and lead-free, 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 MAX696EWE+T, the MAX697EWE+T removes battery-switching circuitry to reduce supply current and add CE gating - making it optimal for write-protected RAM systems without backup power. Versus TPS3808G33DBVR, it delivers integrated watchdog, dual-threshold monitoring, and memory control - eliminating need for three discrete ICs.

Availability

MAX697EWE+T is available at Aetrix Electronics and suitable for industrial PLCs, medical data loggers, telecom remote terminals, and automotive infotainment systems requiring stable component supply across extended temperature ranges.

Supply support for MAX697EWE+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, designs precision analog, mixed-signal, and power-management ICs for demanding industrial, automotive, and communications applications.

The MAX697EWE+T belongs to Maxim's microprocessor supervisory product line, engineered specifically to consolidate power monitoring, reset generation, watchdog supervision, and memory write protection into a single 16-pin IC for space-constrained embedded systems.

FAQ

What is the function of the CE IN and CE OUT pins on the MAX697EWE+T?

The CE IN pin accepts the system's chip-enable or write signal, and CE OUT delivers a gated version that is forced high whenever LLIN falls below 1.3V. This ensures CMOS RAM or EPROM write operations are blocked during brownout conditions. The MAX697EWE+T implements this logic with 80–150ns propagation delay and requires no external components - a key differentiator from discrete solutions.

Does the MAX697EWE+T support battery backup switching like the MAX696?

No, the MAX697EWE+T does not support battery backup switching. It omits the VBATT, VOUT, and BATT ON pins entirely - unlike the MAX696EWE+T. This design choice reduces supply current to ≤300µA and enables inclusion of CE IN/CE OUT logic. If battery switchover is required, MAX696EWE+T is the appropriate variant.

How is the watchdog timeout period selected on the MAX697EWE+T?

The MAX697EWE+T offers two watchdog timeout periods: 100ms and 1.6s. Selection is controlled by the OSC SEL pin and OSC IN pin state. When OSC SEL is high or floating and OSC IN is low, the 100ms period is active; when OSC IN is floating, the 1.6s period is used. After reset, the timeout defaults to 1.6s to allow safe firmware initialization.

What is the purpose of the PFI and PFO pins on the MAX697EWE+T?

The PFI (Power-Fail Input) pin connects to a resistor divider monitoring a regulated or unregulated supply rail. When the voltage at PFI drops below 1.3V, the PFO (Power-Fail Output) pin goes low - providing an early warning interrupt before the main LLIN-triggered RESET activates. This allows the microprocessor to save critical data before system reset occurs.

Can the reset timeout delay of the MAX697EWE+T be adjusted, and how?

Yes, the MAX697EWE+T reset timeout delay defaults to 50ms but can be adjusted using an external capacitor connected between OSC IN and GND. With OSC SEL high/floating, the delay scales inversely with capacitance: e.g., a 47pF capacitor yields ~50ms, while larger values extend the delay linearly. This allows tuning to match specific microprocessor oscillator startup requirements.