Analog Devices Inc./Maxim Integrated MAX696EWE+

Overview

MAX696EWE+ from Maxim Integrated is a microprocessor supervisory circuit designed for industrial-grade power monitoring and battery-backup control in embedded μP systems. It provides six integrated functions: adjustable low-line reset (1.3V threshold), watchdog timer (100ms/1.6s selectable), power-fail warning (1.3V PFI comparator), 50ms reset timeout, battery switchover (VBATT to VOUT), and BATT ON control output. It operates across –40°C to +85°C and supports 3.0V–5.5V VCC with <1μA battery-backup supply current.

For engineers reviewing the MAX696EWE+ datasheet, MAX696EWE+ pinout, MAX696EWE+ application, or MAX696EWE+ equivalent, key selection considerations include its wide-temperature SO-16 package, verified battery-switching capability (not present in MAX697), 1.3V precision reference tolerance (±50mV), and dual-mode watchdog timing configuration via OSC SEL/OSC IN.

Technical Context

The MAX696EWE+ integrates a precision 1.3V bandgap reference shared by LLIN and PFI comparators, enabling independent low-line detection and power-fail warning with ±50mV threshold matching. Its internal oscillator (10.24kHz nominal) drives both reset timeout and watchdog counter logic, with OSC SEL selecting between internal timing or external clock/capacitor-based configuration.

Battery switchover uses a pnp transistor for VCC-to-VOUT switching and a 200Ω MOSFET for VBATT-to-VOUT backup, with 50mV power-down and 70mV power-up thresholds and 20mV hysteresis. The BATT ON output sinks 7mA and directly drives external PNP base current, while RESET and RESET are complementary active-low/active-high outputs with 50ms monostable hold time.

Key Specifications

Pinout & Package

MAX696EWE+ is housed in a 16-pin Wide SO (SOIC-W) surface-mount package, 10.3mm × 7.5mm body, 1.27mm pitch, RoHS-compliant lead-free construction (indicated by '+' suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX697EWE+, MAX696EWE+ provides essential battery-backup switching and VOUT regulation but omits RAM write-protection gating; versus TPS3823-50DBVR, it delivers comprehensive supervision (watchdog, PFI, switchover) at the cost of larger footprint and higher active current-justified in safety-critical, battery-dependent systems.

Availability

MAX696EWE+ is available at Aetrix Electronics and suitable for industrial PLCs, medical infusion pumps, avionics data recorders, and ruggedized handheld test instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX696EWE+ 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, automotive, and communications applications.

The MAX696EWE+ belongs to Maxim's microprocessor supervisory product line, engineered to consolidate reset, watchdog, power-fail, and battery-backup functions into a single IC for reliability-critical embedded systems operating across –40°C to +85°C.

FAQ

What is the primary function of the MAX696EWE+ in a microprocessor system?

The MAX696EWE+ serves as an integrated supervisory circuit that consolidates six critical functions: power-on/power-down reset generation, watchdog timer supervision, battery-backup switchover (VBATT to VOUT), power-fail warning (PFI/PFO), low-line detection (LLIN), and complementary RESET outputs. In a μP system, it ensures reliable startup, continuous software health monitoring, and seamless transition to backup power during main supply failure-directly supporting system robustness in industrial and medical applications.

Does the MAX696EWE+ support adjustable reset timeout, and how is it configured?

Yes, the MAX696EWE+ supports configurable reset timeout. By default, it asserts RESET for 50ms, but this can be adjusted using either an external capacitor on the OSC IN pin (e.g., 47pF yields ~4kHz oscillator, scaling timeout linearly) or by applying an external clock signal when OSC SEL is held low. The datasheet specifies timing ranges from 35ms to 70ms for the default configuration, with wider variation possible under external timing control-enabling precise alignment with specific μP oscillator startup requirements.

How does the battery switchover mechanism work in the MAX696EWE+?

The MAX696EWE+ implements battery switchover by continuously comparing VBATT and VCC. When VCC falls below VBATT minus 70mV, it disconnects VCC from VOUT and connects VBATT via a 200Ω MOSFET, delivering backup power to attached CMOS RAM. When VCC rises above VBATT plus 50mV, it reverts to VCC sourcing. This 20mV hysteresis prevents oscillation near the threshold. During switchover, BATT ON goes high to drive an external PNP transistor, extending VOUT current capability beyond the internal 50mA limit-ensuring uninterrupted memory operation.

Can the MAX696EWE+ monitor both main supply and backup battery voltage simultaneously?

Yes, the MAX696EWE+ monitors both supplies independently. LLIN senses VCC via an external resistor divider to detect brownout conditions using the internal 1.3V reference, while PFI accepts a separate divider from an unregulated rail or the VBATT line itself to generate early power-fail warnings. Crucially, the PFI comparator is automatically disabled and PFO forced low when VCC drops below VBATT-preventing unnecessary battery discharge during backup operation. This dual-path monitoring enables coordinated power sequencing and low-battery alerts without additional components.

What are the key differences between MAX696EWE+ and MAX697EWE+?

The MAX696EWE+ and MAX697EWE+ share identical pinout, temperature rating (–40°C to +85°C), and core supervision features (reset, watchdog, PFI), but differ fundamentally in power architecture: MAX696EWE+ includes VBATT, VOUT, and BATT ON pins for battery-backup switching, whereas MAX697EWE+ replaces those with CE IN and CE OUT pins for CMOS RAM write protection. Consequently, MAX696EWE+ draws 1.5–7mA active current and supports 50mA VOUT loads, while MAX697EWE+ consumes <250µA and lacks switchover capability-making them non-interchangeable in battery-dependent designs.