Analog Devices Inc./Maxim Integrated DS1232S-IBM

Overview

DS1232S-IBM from Maxim Integrated (formerly Dallas Semiconductor) is a microprocessor supervisory circuit that monitors VCC, implements a watchdog timer, and debounces pushbutton reset-providing active-high and open-drain active-low reset outputs. It operates at +5V, supports 5% or 10% VCC tolerance selection via TOL pin, delivers ≥250 ms reset pulse width, and functions across 0°C to +70°C. Used in embedded control systems where reliable power-up sequencing and software fault recovery are critical.

For engineers reviewing the DS1232S-IBM datasheet, DS1232S-IBM pinout, DS1232S-IBM application, or DS1232S-IBM equivalent, key selection criteria include dual-reset output polarity, programmable watchdog timeout (150/600/1200 ms), VCC trip point accuracy (±120 mV), industrial-grade temperature variants, and SOIC-16 package compatibility with legacy DIP-8 layouts.

Technical Context

The DS1232S-IBM integrates three independent monitoring functions: precision VCC detection using a temperature-compensated bandgap reference and comparator, hardware-debounced pushbutton reset with guaranteed 250 ms minimum active pulse, and a non-disableable watchdog timer with three selectable timeout intervals set by TD pin state (GND/float/VCC). All reset outputs remain asserted for ≥250 ms after VCC recovery to ensure processor stabilization.

Its dual RST outputs serve distinct interface roles: RST (Pin 15) is active-high with push-pull drive, while RST (Pin 16) is active-low, open-drain-enabling direct connection to microcontrollers requiring either polarity without external logic. The ST input accepts high-to-low transitions from address/data/control lines to reset the watchdog, and PBRST requires active-low assertion with internal 10 kΩ pull-up.

Key Specifications

Pinout & Package

DS1232S-IBM uses a 16-pin SOIC (300-mil) package with 1.27 mm pitch, footprint compatible with industry-standard SOIC-16 land patterns. Pin 1 is top-left corner, marked by notch or dot; pins 1–8 on top row, 9–16 on bottom row.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX692AESA+ and TPS3823-50DBVR, the DS1232S-IBM offers unique integration of dual-output reset, hardware debounce, and three-point watchdog programming-reducing external component count and enabling robust, self-contained supervision without firmware dependency.

Availability

DS1232S-IBM is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, point-of-sale terminals, and smart energy meters requiring stable component supply and long-term obsolescence management.

Supply support for DS1232S-IBM 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, mixed-signal, and power management ICs for industrial, automotive, communications, and computing applications.

The DS1232 family was developed as a fully integrated MicroMonitor™ solution for microprocessor-based systems needing coordinated power, watchdog, and manual reset supervision in a single 16-pin SOIC package.

FAQ

What is the primary function of the DS1232S-IBM in a microprocessor system?

The DS1232S-IBM serves as a comprehensive supervisory circuit that simultaneously monitors VCC for brown-out conditions, implements a configurable watchdog timer to detect software hangs, and debounces pushbutton reset inputs. It generates both active-high and active-low reset signals to ensure reliable microprocessor initialization and recovery-making it essential for mission-critical embedded systems where unattended operation and power resilience are required. The DS1232S-IBM replaces multiple discrete components with a single, validated IC.

Does the DS1232S-IBM support both 5% and 10% VCC tolerance detection?

Yes, the DS1232S-IBM supports selectable VCC tolerance thresholds via the TOL pin: connecting TOL to GND configures a 4.62 V trip point (5% of 5 V), while connecting TOL to VCC sets a 4.37 V threshold (10% of 5 V). This allows system designers to match the DS1232S-IBM's detection sensitivity to their specific power supply regulation and noise margin requirements without external resistors. The DS1232S-IBM's internal precision reference ensures ±120 mV accuracy across temperature.

Can the watchdog timer in the DS1232S-IBM be disabled?

No, the watchdog timer in the DS1232S-IBM cannot be disabled-it must be actively strobed via the ST input to prevent timeout-induced reset assertion. A high-to-low transition on ST resets the internal timer, and failure to strobe within the selected interval (150/600/1200 ms) forces both RST outputs active for ≥250 ms. This design ensures fail-safe behavior: if firmware stops executing or fails to service the watchdog, the DS1232S-IBM automatically recovers the system. The DS1232S-IBM enforces this requirement per its datasheet specification.

What are the electrical characteristics of the two RST outputs on the DS1232S-IBM?

The DS1232S-IBM provides two physically separate reset outputs: Pin 15 (RST) is an active-high push-pull driver capable of sourcing/sinking ≥8 mA at 2.4 V/0.4 V, while Pin 16 (RST) is an active-low open-drain output requiring an external pull-up resistor. The open-drain RST supports mixed-voltage interfaces and wired-OR configurations, whereas the push-pull RST drives standard CMOS/TTL inputs directly. Both outputs are guaranteed to remain asserted for ≥250 ms after VCC recovery. These dual-output characteristics are intrinsic to the DS1232S-IBM's architecture.

Is the DS1232S-IBM RoHS-compliant?

No, the DS1232S-IBM is not RoHS-compliant, as indicated by its "IBM" suffix and official Maxim Integrated packaging documentation. The "IBM" designation specifies non-RoHS, leaded solder finish in a 16-pin SOIC package rated for 0°C to +70°C operation. For RoHS-compliant alternatives, consider DS1232S+ (same package, lead-free) or DS1232SN+ (industrial temperature, lead-free). Always verify compliance status against current manufacturer datasheets before design-in, as the DS1232S-IBM's material composition excludes RoHS exemptions.