Analog Devices Inc./Maxim Integrated DS1708EPA

Overview

DS1708EPA from Maxim Integrated is a 5.0V microprocessor supervisory circuit with 10% reset threshold, active-low and active-high reset outputs, non-maskable interrupt (NMI), and pushbutton reset debouncing. It monitors VCC supply voltage, an external sense point via IN pin, and user-initiated reset. Designed for industrial embedded systems requiring reliable power-up/power-down sequencing and early power-fail warning.

For engineers reviewing the DS1708EPA datasheet, DS1708EPA pinout, DS1708EPA application, or DS1708EPA equivalent, key selection criteria include its 4.25V–4.50V VCC trip point, 130ms minimum reset pulse width, NMI generation at 1.25V IN threshold, and compatibility with 8-pin DIP packaging for legacy board layouts.

Technical Context

The DS1708EPA implements dual-voltage monitoring: internal VCC detection triggers RST and RST outputs on undervoltage, while external voltage sensing at the IN pin (with 1.20V–1.30V trip) generates a 200µs NMI pulse. Its precision bandgap reference enables ±5% tolerance over temperature.

Reset assertion is synchronized to VCC decay and recovery, with built-in hysteresis (100µV on NMI path) and noise immunity against <2µs transients. The PBRST input is internally pulled up (40kΩ typical) and debounced to guarantee ≥130ms reset pulse width upon button release.

Key Specifications

Pinout & Package

DS1708EPA uses an 8-pin plastic DIP (300-mil) package with industry-standard footprint and lead spacing. Pin assignments are fixed per mechanical drawing and validated across Maxim's DS1707/DS1708 family.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX708ESA and TPS3808G12DBVR, DS1708EPA uniquely integrates three independent supervision functions-VCC monitoring, external sense with NMI, and debounced pushbutton reset-in a single 8-pin DIP, eliminating discrete support circuitry and enabling deterministic fault response without layout changes.

Availability

DS1708EPA is available at Aetrix Electronics and suitable for industrial control systems, medical diagnostics hardware, telecom infrastructure management, and smart energy metering requiring stable component supply and long-term obsolescence planning.

Supply support for DS1708EPA 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 markets.

The DS1707/DS1708 MicroMonitor product line was designed to replace discrete reset circuits in microprocessor-based systems, delivering integrated voltage supervision, interrupt signaling, and pushbutton control in standard packages.

FAQ

What is the exact VCC trip point range for DS1708EPA?

The DS1708EPA has a guaranteed VCC trip point range of 4.25V (minimum) to 4.50V (maximum) at -40°C to +85°C, corresponding to a nominal 10% undervoltage threshold for 5.0V systems. This specification is verified per Maxim's DS1707/DS1708 datasheet revision, and applies specifically to the DS1708EPA variant-not DS1707 or DS1708T/S/R versions. DS1708EPA maintains this tolerance across full industrial temperature range without external calibration.

Does DS1708EPA provide both active-low and active-high reset outputs?

Yes, DS1708EPA provides two dedicated reset outputs: RST (active-low, open-drain) and RST (active-high, push-pull). These outputs are asserted simultaneously during VCC undervoltage, PBRST activation, or IN-triggered NMI-to-reset chaining. The dual-output architecture eliminates need for external level-shifting or inversion, making DS1708EPA directly compatible with both TTL and CMOS microprocessors requiring either reset polarity.

Can DS1708EPA monitor a 12V supply, and how is that implemented?

Yes, DS1708EPA can monitor a 12V supply using its IN pin with an external resistor divider. Since the IN trip point is fixed at 1.25V, a divider such as R1 = 26kΩ and R2 = 10kΩ scales 12V down to 3.33V at IN-exceeding the 1.25V threshold. Per datasheet Figure 5, maximum allowable monitored voltage (VMAX) is calculated as (VCC × VTP) / VSENSE; with VCC = 5.0V and VSENSE = 4.50V, VMAX = 11.88V. Thus, DS1708EPA safely monitors up to ~11.9V with proper resistor selection.

What is the function of the NMI output on DS1708EPA, and how does it differ from RST?

The NMI output on DS1708EPA delivers a 200µs active-low pulse when the IN pin voltage falls below 1.25V, providing early warning of power failure before VCC drops to its trip point. Unlike RST-which asserts only after VCC decay-NMI enables preemptive actions like saving volatile data or disabling peripherals. DS1708EPA's NMI has 100µV hysteresis and ignores noise spikes <2µs, ensuring robust operation. NMI is electrically isolated from RST timing paths and can be routed independently to CPU NMI pins.

Is DS1708EPA pin-compatible with other members of the DS1707/DS1708 family?

Yes, DS1708EPA is fully pin-compatible with DS1707EPA, DS1708ESA, DS1708REPA, and all other variants in the DS1707/DS1708 family sharing the 8-pin DIP (300-mil) package. Pin functions-including PBRST, VCC, GND, IN, RST, RST, NC, and NMI-are identical across these parts. Differences lie solely in trip-point specifications (e.g., DS1707 = 4.50V–4.75V, DS1708 = 4.25V–4.50V) and temperature grade; no PCB redesign is needed when substituting within same package type.