Analog Devices Inc./Maxim Integrated MAX708SEPA

Overview

MAX708SEPA from Maxim Integrated is an 8-pin PDIP-packaged microprocessor supervisory circuit designed for +3V to +5V systems, providing active-high and active-low reset outputs, a 2.93V precision reset threshold, 200ms reset pulse width, and a 1.25V power-fail comparator input-used in battery-powered instruments to ensure reliable µP startup and orderly shutdown during brownout.

For engineers reviewing the MAX708SEPA datasheet, MAX708SEPA pinout, MAX708SEPA application, or MAX708SEPA equivalent, this page delivers verified functional identity, exact reset threshold (2.93V), dual-reset output behavior, PFI/PFO monitoring capability, and validated alternatives for critical power-monitoring designs.

Technical Context

The MAX708SEPA implements a dual-reset generator with independent RESET (active-high) and RESET (active-low) outputs, both asserted when VCC falls below 2.93V or MR is pulled low, and deasserted after a guaranteed 200ms delay upon recovery. It integrates a precision 1.25V reference for external power-fail detection via PFI/PFO, with <25nA input leakage and 10mV hysteresis.

Unlike MAX706 variants, the MAX708SEPA omits the watchdog timer and WDI/WDO pins entirely, dedicating all eight pins to supply monitoring, manual reset, and dual-reset signaling-making it suitable for cost-sensitive, watchdog-free µP supervision where deterministic reset polarity control is required.

Key Specifications

Pinout & Package

MAX708SEPA is housed in an 8-pin plastic DIP (PDIP) package (package code P8-1), through-hole mountable, lead-free compatible, with 0.3" wide body and standard 0.1" pin pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX708SEA and TPS3808G33DBVR, the MAX708SEPA uniquely delivers both reset polarities in a through-hole package with integrated power-fail detection-reducing BOM count and layout complexity where mechanical serviceability and auxiliary rail monitoring are essential.

Availability

MAX708SEPA is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial controller supervision, and portable medical device designs requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX708SEPA 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, communications, and computing markets.

The MAX708 family was designed specifically for cost-effective, precision µP supervision in +3V/+3.3V systems-emphasizing dual-reset flexibility, low quiescent current, and integrated power-fail warning without watchdog overhead.

FAQ

What is the reset threshold voltage of the MAX708SEPA?

The MAX708SEPA has a guaranteed reset threshold of 2.93V (VCC falling), with ±1.5% tolerance over its full -40°C to +85°C operating range. This value is factory-trimmed and specified in the Electrical Characteristics table under "Reset Threshold (VCC Falling)" for the 'S' suffix variant. The MAX708SEPA asserts both RESET and RESET outputs when VCC drops below this threshold and maintains them for ≥200ms after VCC recovers above it.

Does the MAX708SEPA include a watchdog timer function?

No, the MAX708SEPA does not include a watchdog timer. Unlike the MAX706 series, the MAX708 family replaces the WDI and WDO pins with a second reset output (RESET). Pin 6 is RESET (active-low) and pin 8 is RESET (active-high); pins 6 and 8 on MAX706 variants are WDO and N.C., respectively. This makes MAX708SEPA ideal for applications requiring deterministic reset control without software-managed timeout supervision.

What is the purpose of the PFI and PFO pins on the MAX708SEPA?

The PFI (Pin 4) is the inverting input of an internal 1.25V comparator; connecting it to a resistive divider allows monitoring of auxiliary supplies (e.g., unregulated DC or negative rails). When PFI voltage falls below 1.25V, PFO (Pin 5) goes active-low to signal power-fail or low-battery condition. PFO can drive a µP interrupt or be tied to MR to initiate a supervised shutdown-enabling early-warning capability beyond main-supply monitoring.

Can the MAX708SEPA operate with a 1.2V supply?

Yes, the MAX708SEPA is fully specified to operate down to VCC = 1.2V over its entire -40°C to +85°C temperature range. Its RESET output is guaranteed to remain logic-low and RESET logic-high for VCC ≥ 1.2V, and both reset outputs assert reliably even as VCC declines toward 1.2V. This ensures fail-safe behavior during deep brownout conditions where other supervisors may lose functionality.

Is the MAX708SEPA pin-compatible with other MAX708 variants?

Yes, all MAX708R/S/T variants-including MAX708SEPA-are pin-compatible across package types (PDIP, SO, µMAX) and temperature grades. The 'R', 'S', and 'T' suffixes denote different reset thresholds (2.63V, 2.93V, 3.08V), but share identical pin functions, timing, and electrical behavior. Thus, MAX708SEPA can be substituted for MAX708REPA or MAX708TEPA on the same PCB, provided the 2.93V threshold meets system requirements.