Analog Devices Inc./Maxim Integrated MAX1232CWE

Overview

The MAX1232CWE from Maxim Integrated is a microprocessor supervisory circuit that monitors +5V power supply voltage, provides debounced manual reset, and implements a digitally programmable watchdog timer with 150ms/600ms/1.2s timeout options. It delivers active-high and open-drain active-low reset outputs with ≥250ms pulse width, operates from 0°C to +70°C, and requires no external components for full functionality in embedded μP systems.

For engineers reviewing the MAX1232CWE datasheet, MAX1232CWE pinout, MAX1232CWE application, or MAX1232CWE equivalent, key selection criteria include its dual-reset output architecture, selectable 5%/10% VCC trip thresholds, guaranteed 250ms reset hold time, wide-SO16 package compatibility, and direct upgrade path from DS1232 in industrial controllers and intelligent instruments.

Technical Context

The MAX1232CWE integrates three core supervision functions: precision voltage monitoring with digitally selected 4.62V (5%) or 4.37V (10%) trip points, a falling-edge-triggered watchdog timer whose timeout is set by TD pin voltage (GND/open/VCC), and a debounced pushbutton reset input (PBRST) that ignores <1ms glitches and guarantees recognition of ≥20ms pulses.

Its dual RST outputs serve complementary roles: RST sources/sinks current for direct μP reset assertion, while RST is open-drain for wired-OR configurations or level translation. All timing parameters-including reset active time (250–1000ms), PBRST delay (1–20ms), and ST strobe timeout-are fully specified across temperature and supply voltage (4.5V–5.5V).

Key Specifications

Pinout & Package

The MAX1232CWE is supplied in a 16-pin Wide SO package (package code W16+1, outline 21-0042), measuring 10.3mm × 7.5mm with 1.27mm pitch. Pin 1 is located at the top-left corner adjacent to the index mark.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1232CSA and DS1232LN+, the MAX1232CWE offers superior flexibility via its wide-SO16 layout (enabling cleaner routing of dual RST lines), 1/10th the supply current of DS1232, and field-programmable watchdog timeout-making it optimal for new designs demanding low power, configurability, and layout robustness.

Availability

MAX1232CWE is available at Aetrix Electronics and suitable for industrial controllers, intelligent instruments, and critical μP power monitoring applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1232CWE 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, computing, and communications markets.

The MAX1232 product line delivers highly integrated microprocessor supervisory solutions targeting embedded systems where reliability, low power, and minimal external components are essential design constraints.

FAQ

What is the operating temperature range for the MAX1232CWE?

The MAX1232CWE is rated for operation from 0°C to +70°C ambient temperature. This commercial-grade specification aligns with standard industrial control and instrumentation environments where extended thermal stress is not expected. The device's DC and AC electrical characteristics-including reset timing, voltage trip accuracy, and leakage currents-are fully guaranteed across this range per the datasheet's Recommended Operating Conditions table.

How does the MAX1232CWE select between 5% and 10% VCC tolerance?

The MAX1232CWE selects its VCC trip threshold using the TOL pin: connecting TOL to GND configures a 5% tolerance (typical 4.62V trip), while connecting TOL to VCC selects 10% tolerance (typical 4.37V trip). This selection directly determines the voltage at which RST and RST assert during brownout. The MAX1232CWE's internal reference and comparator circuitry guarantee these thresholds across temperature and supply variations without external calibration.

Can the MAX1232CWE replace the DS1232 without PCB changes?

No, the MAX1232CWE cannot replace the DS1232 without PCB changes because it uses a 16-pin Wide SO package (W16+1), whereas the DS1232 uses an 8-pin PDIP or SO package. Although the MAX1232CWE is described as a "plug-in upgrade" in functional capability, its pin count, pinout, and physical dimensions differ significantly. A redesign is required to accommodate the MAX1232CWE's wider body and additional N.C. pins.

What is the minimum pulse width required on the PBRST pin to guarantee reset activation in the MAX1232CWE?

The MAX1232CWE guarantees reset activation when the PBRST pin is held low for a minimum of 20ms, as specified in Note 5 of the datasheet. Pulses shorter than 1ms are ignored due to internal debouncing, and the device's PBRST delay (tPBD) ranges from 1ms to 20ms depending on process and temperature. Therefore, a 20ms low pulse ensures reliable recognition and initiation of the full 250ms reset pulse on both RST and RST outputs.

Does the MAX1232CWE require external components to operate?

No, the MAX1232CWE requires no external components to perform its core supervisory functions: power monitoring, watchdog timing, and manual reset. Its internal voltage reference, comparators, timers, and pull-up on PBRST eliminate the need for external resistors, capacitors, or diodes. This integration reduces BOM cost, improves reliability, and simplifies layout-confirmed by the "No External Components" feature explicitly stated in the datasheet's Features section.