Analog Devices Inc. ADM1232AN

Overview

ADM1232AN from Analog Devices is a 5 V microprocessor supervisory circuit in an 8-lead PDIP package, featuring adjustable voltage monitoring (4.5 V or 4.75 V trip), programmable strobe timeout (150 ms/600 ms/1.2 s), push-button reset with 20 ms debounce, and dual active-high/active-low RESET outputs. It monitors supply voltage integrity, microprocessor lockup via STROBE activity, and external reset requests in embedded control systems.

For engineers reviewing the ADM1232AN datasheet, ADM1232AN pinout, ADM1232AN application, or ADM1232AN equivalent, this device serves as a precision power-on reset and watchdog supervisor for 5 V microcontroller-based systems where reliable power sequencing, brownout detection, and manual reset recovery are required.

Technical Context

The ADM1232AN integrates a precision voltage comparator with selectable 5% or 10% tolerance thresholds, a monostable watchdog timer triggered by STROBE edge transitions, and a debounced PB RESET input. Its dual RESET outputs provide both push-pull (RESET) and open-drain (RESET) drive capabilities for flexible interface to diverse logic families and reset architectures.

It operates across −40°C to +85°C with 20–50 μA quiescent current, uses no external components, and asserts reset within 50 μs of VCC falling below the trip point. The TD pin selects strobe timeout periods by setting bias conditions-0 V, floating, or VCC-enabling three discrete timing windows without capacitors or resistors.

Key Specifications

Pinout & Package

ADM1232AN is housed in an 8-lead plastic dual in-line package (PDIP, N-8) with 0.3-inch body width and through-hole mounting. Pin 1 is PB RESET; Pin 4 is TD; Pin 3 is TOLERANCE; Pin 5 is GND; Pin 6 is RESET; Pin 7 is STROBE; Pin 8 is VCC; Pin 2 is RESET.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM1232AN, MAX1232CPA+ offers identical functionality with marginally higher quiescent current, while DS1232LPN+ delivers equivalent performance at lower static power-both require no PCB changes but differ in manufacturer lifecycle support and qualification documentation.

Availability

ADM1232AN is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical infusion pumps, and point-of-sale terminal power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM1232AN 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.

The ADM1232AN belongs to Analog Devices' microprocessor supervisory IC product line, engineered specifically for robust power monitoring and watchdog supervision in mission-critical embedded systems where deterministic reset behavior and long-term reliability are mandatory.

FAQ

What is the exact VCC trip voltage for ADM1232AN when TOLERANCE is grounded?

When the TOLERANCE pin is connected to GND, the ADM1232AN asserts RESET at a nominal 4.75 V VCC trip point, corresponding to a 5% tolerance below 5 V. This value is guaranteed across −40°C to +85°C with a min/max range of 4.62 V to 4.74 V per the Rev. C datasheet Table 1. The ADM1232AN uses internal trimming to achieve this precision without external components.

Can ADM1232AN replace MAX1232 in an existing design without layout changes?

Yes, ADM1232AN is pin-compatible and functionally equivalent to MAX1232, including identical pinout, timing parameters, and electrical specifications. The ADM1232AN datasheet explicitly states "pin-compatible with MAX1232", and both use the same 8-lead PDIP (N-8) package. No PCB modifications are required for direct substitution in legacy MAX1232 designs.

How does the TD pin configure the strobe timeout period on ADM1232AN?

The TD pin on ADM1232AN selects one of three strobe timeout periods: 150 ms (TD = 0 V), 600 ms (TD = floating), or 1.2 s (TD = VCC). This is achieved by internal biasing circuitry that interprets TD's voltage state-no external resistors or capacitors are needed. The timeout defines the maximum allowed interval between STROBE high-to-low transitions before a reset is generated.

What is the difference between the RESET and RESET outputs on ADM1232AN?

On ADM1232AN, RESET is an active-high push-pull output capable of sourcing and sinking up to 10 mA, directly driving TTL/CMOS inputs. RESET is an active-low open-drain output requiring an external pull-up resistor; it enables wired-OR reset buses, level shifting, or interfacing with multiple voltage domains. Both outputs are asserted simultaneously during reset events.

Does ADM1232AN support operation at 3.3 V supply rails?

No, ADM1232AN is specified exclusively for 5 V operation (4.5 V to 5.5 V VCC range) and is not rated for 3.3 V supply rails. Its internal voltage reference, comparators, and output drivers are optimized for 5 V logic levels and trip thresholds. For 3.3 V systems, Analog Devices recommends alternatives such as ADM6803 or ADM6805, which are designed for lower supply voltages.