Analog Devices Inc./Maxim Integrated DS1232S/T&R

Overview

DS1232S/T&R from Maxim Integrated (formerly Dallas Semiconductor) is a microprocessor supervisory circuit that monitors VCC, implements pushbutton reset with 250 ms debounce, and provides a configurable watchdog timer with timeout options of 150 ms, 600 ms, or 1.2 s. It delivers dual active-high and open-drain active-low reset outputs and operates over 4.5 V to 5.5 V supply at -40°C to +85°C industrial temperature range. Used in embedded controllers where reliable power-up sequencing and fault recovery are critical.

For engineers reviewing the DS1232S/T&R datasheet, DS1232S/T&R pinout, DS1232S/T&R application, or DS1232S/T&R equivalent, key selection considerations include its dual-reset output architecture, TOL-selectable 5% or 10% VCC threshold, ST-driven watchdog timing control, PBRST debounced pushbutton interface, and compatibility with 5 V microprocessor systems requiring guaranteed 250 ms reset assertion on power-up and power-down.

Technical Context

The DS1232S/T&R integrates three independent monitoring functions: precision voltage detection using a temperature-compensated bandgap reference and comparator, hardware-debounced pushbutton reset with fixed 250 ms minimum pulse width, and a non-disableable watchdog timer whose timeout is set via TD pin logic state (GND/float/VCC). All functions drive both RST (active-high) and RST (open-drain active-low) outputs simultaneously.

Power monitoring triggers reset when VCC falls below 4.50 V (TOL = VCC) or 4.75 V (TOL = GND), with hysteresis ensuring clean release. The watchdog requires periodic ST strobe transitions; failure to strobe within the selected timeout causes automatic 250 ms reset assertion. No external components are required for basic operation.

Key Specifications

Pinout & Package

DS1232S/T&R is supplied in a 16-pin SOIC (300-mil) surface-mount package. Pin assignments are validated per Maxim's official DS1232/DS1232S datasheet Rev. 0, pages 2–3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX692AESA+ and TPS3823-50DBVR, DS1232S/T&R uniquely combines dual-reset polarity, user-selectable VCC threshold, integrated pushbutton debounce, and configurable watchdog-all in a single 16-pin SOIC-making it optimal for space-constrained, self-recovering embedded systems needing full hardware supervision.

Availability

DS1232S/T&R is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, telecom remote terminal units, and smart energy meters requiring stable component supply and long-lifecycle support.

Supply support for DS1232S/T&R 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 (acquired by Analog Devices in 2021) designs precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The DS1232S/T&R belongs to Maxim's MicroMonitor™ family of supervisory circuits, engineered specifically for robust, component-level reset and watchdog control in 5 V microprocessor systems deployed in harsh or safety-critical environments.

FAQ

What is the function of the TOL pin on the DS1232S/T&R?

The TOL pin on the DS1232S/T&R selects the VCC detection threshold: connecting TOL to GND sets a 4.75 V trip point (5% tolerance), while connecting it to VCC sets a 4.50 V trip point (10% tolerance). This allows field-configurable brown-out sensitivity without changing the bill of materials. The DS1232S/T&R uses this setting to determine when to assert RST and RST during power failure or startup.

Does the DS1232S/T&R provide both active-high and active-low reset outputs?

Yes, the DS1232S/T&R provides two independent reset outputs: RST is a push-pull active-high output, and the second RST is an open-drain active-low output. Both are asserted simultaneously during power-up, power-down, watchdog timeout, or pushbutton event. This dual-output architecture eliminates the need for external inverters or level shifters when interfacing with MCUs requiring either reset polarity.

How is the watchdog timeout configured on the DS1232S/T&R?

The watchdog timeout on the DS1232S/T&R is set by the logic state of the TD pin: grounded for ~150 ms, left floating for ~600 ms, or tied to VCC for ~1.2 s. The watchdog cannot be disabled and requires periodic ST input strobes to prevent timeout. Each timeout option is factory-characterized and specified in the DS1232S/T&R datasheet Table 1.

What is the minimum reset pulse width guaranteed by the DS1232S/T&R?

The DS1232S/T&R guarantees a minimum reset pulse width of 250 ms for all reset sources: power-up, power-down, pushbutton activation, and watchdog timeout. This duration is fixed and does not vary with temperature or supply voltage. The DS1232S/T&R holds both RST outputs active for this full interval to ensure complete microprocessor initialization and peripheral stabilization.

Is the DS1232S/T&R compatible with industrial temperature requirements?

Yes, the DS1232S/T&R is rated for operation from -40°C to +85°C, meeting industrial temperature specifications. This rating is confirmed in the "Absolute Maximum Ratings" and "Recommended DC Operating Conditions" sections of the official DS1232/DS1232S datasheet. The DS1232S/T&R maintains full functionality-including VCC detection accuracy, watchdog timing, and reset pulse width-across this full range.