Analog Devices Inc./Maxim Integrated MAX708CUA+

Overview

MAX708CUA+ from Maxim Integrated is a microprocessor supervisory circuit providing active-high reset output, 4.40V supply-voltage monitoring, power-fail warning via 1.25V threshold comparator, and manual-reset input - all in an 8-pin µMAX package. It ensures reliable power-up/power-down sequencing and brownout protection for +5V systems in industrial controllers and embedded instrumentation.

For engineers reviewing the MAX708CUA+ datasheet, MAX708CUA+ pinout, MAX708CUA+ application, or MAX708CUA+ equivalent, key selection criteria include guaranteed RESET validity down to VCC = 1V, 200ms reset pulse width, debounced TTL/CMOS-compatible MR input, and compatibility with 5V logic interfaces requiring active-high reset assertion.

Technical Context

The MAX708CUA+ implements a precision bandgap-based voltage monitor with 4.40V ±150mV reset threshold and 40mV hysteresis, ensuring stable reset assertion during supply transients. Its internal timer guarantees a minimum 140ms (typ. 200ms) active-high RESET pulse upon power-up or MR activation.

Unlike the MAX705/MAX706 series, the MAX708CUA+ omits the watchdog timer and WDO output, substituting a dedicated active-high RESET output. The PFI input accepts 1.25V threshold detection for power-fail or low-battery warning, with leakage current under ±25nA enabling high-impedance voltage-divider monitoring.

Key Specifications

Pinout & Package

MAX708CUA+ uses an 8-pin µMAX package (outline 21-0036), 3.0mm × 3.0mm body, 0.5mm pitch, exposed pad for thermal enhancement. Pin 1 marked by dot; top view orientation matches standard µMAX layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX707CUA+, MAX708CUA+ provides lower reset threshold for wider brownout coverage; versus MAX813LCUA+, it removes watchdog complexity and reduces BOM count where supervision is limited to power monitoring.

Availability

MAX708CUA+ is available at Aetrix Electronics and suitable for industrial controllers, medical instrumentation, automotive infotainment systems, and smart energy meters requiring stable component supply across extended production lifecycles.

Supply support for MAX708CUA+ 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 industrial, communications, and computing applications, with emphasis on power management and interface solutions.

The MAX705–MAX708 family delivers integrated microprocessor supervisory functions - reset generation, power-fail detection, and manual reset - optimized for space-constrained 5V embedded systems requiring high reliability and low quiescent current.

FAQ

What is the reset threshold voltage for MAX708CUA+?

The MAX708CUA+ has a nominal reset threshold of 4.40V with ±150mV tolerance, meaning RESET deasserts when VCC rises above ~4.25V and asserts when VCC falls below ~4.55V. This threshold is factory-trimmed and applies across the full 0°C to +70°C temperature range. The 40mV hysteresis prevents chatter during slow supply ramps. This value is specific to MAX708CUA+ and differs from the 4.65V threshold used in MAX705/MAX707 variants.

Does MAX708CUA+ include a watchdog timer function?

No, MAX708CUA+ does not include a watchdog timer. Unlike MAX705/MAX706/MAX813L, the MAX708CUA+ substitutes the watchdog circuitry with a second reset output configuration - specifically, an active-high RESET pin. Pins 1 (WDO) and 3 (WDI) are designated No Connect (NC) in the MAX708CUA+ pinout. This simplifies design where only power-supply supervision is required, eliminating watchdog timing constraints and associated PCB routing.

Can MAX708CUA+ monitor voltages other than +5V?

Yes, MAX708CUA+ can monitor auxiliary supplies using the PFI input. By connecting a resistor divider between the target voltage (e.g., +12V or +3.3V) and GND, the voltage at PFI is scaled to match the 1.25V internal reference. For example, a 10kΩ/1.33kΩ divider on a +12V rail yields ~1.25V at PFI. The PFI input draws less than ±25nA, minimizing loading error. This capability is explicitly supported in the MAX708CUA+ datasheet and validated in typical operating circuits.

What is the minimum VCC required for valid RESET output in MAX708CUA+?

MAX708CUA+ guarantees valid RESET output down to VCC = 1.0V. At 1.0V, the RESET pin maintains logic-level compatibility with downstream CMOS inputs, sinking ≤0.3V when asserted. This feature enables controlled shutdown sequences during deep brownout conditions where other supervisors may lose output drive capability. The specification is tested and guaranteed over temperature and process variation, not estimated or derived.

Is MAX708CUA+ RoHS-compliant and lead-free?

Yes, MAX708CUA+ is RoHS-compliant and lead-free. The "+" suffix in the part number explicitly denotes lead(Pb)-free/RoHS-compliant packaging per Maxim Integrated's ordering conventions. Devices are assembled in 8-pin µMAX packages using matte-tin lead finish, qualified to JEDEC J-STD-020 moisture sensitivity level 1, and compatible with standard Pb-free reflow profiles (peak 260°C). This compliance is documented in the official Maxim ordering information table.