Analog Devices Inc./Maxim Integrated DS1238-10N

Overview

DS1238-10N from Maxim Integrated (now Analog Devices) is a microprocessor supervisory IC providing power-fail detection, watchdog reset control, non-maskable interrupt generation, SRAM backup switching, and battery-freshness sealing in embedded systems. It features 10% VCC trip point (4.5 V), dual active-low/active-high RST outputs, 200 nA battery current, and 16-pin DIP/SOIC packaging. Used in industrial controllers for orderly shutdown during brownouts.

For engineers reviewing the DS1238-10N datasheet, DS1238-10N pinout, DS1238-10N application, or DS1238-10N equivalent, key selection criteria include VCC trip accuracy (±0.13 V), watchdog timeout flexibility (170 ms to 2.7 s), IN pin early-warning threshold (1.27 V), CEO propagation delay (20 ns), and VCCO output capability (100 mA at VCC–0.3 V).

Technical Context

The DS1238-10N integrates a bandgap voltage reference and precision comparator to monitor VCC with 10% tolerance (VCCTP = 4.25–4.50 V). Its dual RST outputs provide simultaneous active-low and active-high reset signals with 40–150 ms minimum assertion time after VCC recovery.

A programmable watchdog timer uses either internal ring oscillator (~30 kHz) or external capacitor timing, supporting configurable timeout periods (170 ms short, 2.7 s long). The IN pin enables user-defined early-warning voltage sensing via resistor divider, triggering NMI when input falls below 1.15–1.35 V.

Key Specifications

Pinout & Package

DS1238-10N is available in 16-pin plastic DIP (300-mil) and 16-pin SOIC (300-mil) packages. Both share identical pin mapping and thermal characteristics for drop-in compatibility across prototyping and production.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1238-10N, MAX691CPD+ offers identical pinout but omits critical early-warning and battery-seal functions, while DS1233M-10+ reduces functionality to basic reset generation-neither provides the integrated SRAM backup, watchdog, or NMI capabilities essential for robust embedded data retention.

Availability

DS1238-10N is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, telecom infrastructure, and smart energy metering requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for DS1238-10N 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

Analog Devices (via acquisition of Maxim Integrated) designs high-reliability analog and mixed-signal ICs for precision power management, sensing, and timing applications in harsh environments.

The DS1238-10N belongs to Maxim's MicroManager family, engineered specifically for microprocessor-based systems needing coordinated power monitoring, reset control, SRAM backup, and orderly shutdown under brownout conditions.

FAQ

What is the exact VCC trip point specification for DS1238-10N?

The DS1238-10N has a guaranteed VCC trip point (VCCTP) of 4.25 V (min), 4.37 V (typ), and 4.50 V (max) - corresponding to 10% tolerance around nominal 5 V supply. This ensures reset activation before microprocessor operational limits are exceeded, and is distinct from the DS1238-5 variant (4.75 V trip). DS1238-10N maintains this specification across 0°C to 70°C commercial temperature range.

How does DS1238-10N implement early-warning power-fail detection?

DS1238-10N uses its IN pin to monitor a user-defined voltage threshold via external resistor divider. When voltage at IN falls below 1.15–1.35 V (VTP), it asserts active-low NMI to notify the microprocessor of impending power loss. Three consecutive 33 µs samplings below threshold prevent noise-induced false triggers. DS1238-10N then provides ~100 µs to several milliseconds of warning time before RST activation, enabling critical data save operations.

Can DS1238-10N directly power SRAM during battery backup?

Yes. DS1238-10N provides VCCO output that automatically switches between VCC and VBAT (whichever is higher), delivering up to 100 mA at VCC–0.3 V or VBAT–0.8 V. During VCC failure, VCCO sustains SRAM VDD from battery with <0.8 V dropout, enabling nonvolatile operation. DS1238-10N also asserts CEO to disable chip enable and prevent writes, completing the full SRAM backup sequence.

What watchdog timeout options does DS1238-10N support?

DS1238-10N supports two primary watchdog timeout modes: internal ring oscillator (170 ms short, 2.7 s long) or external capacitor timing (e.g., 47 pF yields ~2.2 sec first timeout). Configuration is controlled by OSCSEL pin state and OSCIN connection. DS1238-10N requires ST pin strobing before timeout expiration to reset the watchdog; failure results in WDS assertion and RST/RST activation.

Does DS1238-10N support industrial temperature range?

The DS1238-10N is specified for 0°C to 70°C operation per datasheet Absolute Maximum Ratings and DC Operating Conditions. An industrial-grade version (–40°C to +85°C) exists as DS1238S-10N, but DS1238-10N itself is not rated for industrial temperatures. Using DS1238-10N outside 0–70°C may result in parametric shift or functional failure; verify ambient conditions before deployment.