Analog Devices Inc./Maxim Integrated DS1233M-55+T&R

Overview

DS1233M-55+T&R from Maxim Integrated (now Analog Devices) is a precision voltage-monitoring microprocessor supervisory circuit in TO-92 package, providing active-low reset assertion during VCC undervoltage or power failure, with 4.5V to 4.75V high-trip threshold, 350 ms minimum reset pulse width, and -40°C to +85°C operating range - used in embedded microcontroller power-up sequencing and brownout protection.

For engineers reviewing the DS1233M-55+T&R datasheet, DS1233M-55+T&R pinout, DS1233M-55+T&R application, or DS1233M-55+T&R equivalent, key selection criteria include trip voltage accuracy (±125 mV), guaranteed 350 ms reset timeout, internal 5 kΩ pullup, compatibility with Motorola 68XXX/HC16 families, and TO-92 mechanical fit for legacy board space constraints.

Technical Context

The DS1233M-55+T&R implements a temperature-compensated bandgap reference and comparator to detect VCC deviations beyond its factory-trimmed 4.5V–4.75V high-trip window. It asserts RST low on out-of-tolerance detection and holds it active for ≥350 ms after VCC recovery, independent of external timing components.

No external capacitor or resistor is required for basic operation due to integrated 5 kΩ pullup and internal timing circuitry. Its pinout and logic behavior are functionally aligned with MC33064/MC34064 series, enabling drop-in replacement in existing designs using those parts.

Key Specifications

Pinout & Package

DS1233M-55+T&R is supplied in TO-92 package (3-pin, through-hole), with lead finish Pb-free per JEDEC J-STD-020, and RoHS-compliant marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX691ACPA+ and TPS3808G33DBVR, DS1233M-55+T&R delivers fixed 4.5–4.75 V trip accuracy, guaranteed 350 ms reset hold, and TO-92 drop-in fit - making it optimal for cost-sensitive, space-constrained industrial upgrades where minimal redesign is required.

Availability

DS1233M-55+T&R is available at Aetrix Electronics and suitable for industrial control panels, legacy automotive electronics, and medical device power management requiring stable component supply over extended production lifecycles.

Supply support for DS1233M-55+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

Analog Devices (acquired Maxim Integrated in 2021) designs high-performance analog, mixed-signal, and power management ICs for precision sensing, signal conditioning, and system supervision.

The DS1233M-55+T&R belongs to Maxim's EconoReset™ supervisory product line, engineered specifically for cost-effective, single-supply microprocessor reset generation in resource-constrained embedded systems.

FAQ

What is the exact voltage trip window for DS1233M-55+T&R?

The DS1233M-55+T&R has a factory-trimmed high-trip level (VHTL) of 4.75 V and low-trip level (VLTL) of 4.00 V. This 750 mV hysteresis window ensures robust immunity to noise-induced false resets while guaranteeing clean release once VCC stabilizes above 4.00 V. The DS1233M-55+T&R datasheet specifies ±125 mV tolerance on VHTL, confirming tight production consistency.

Does DS1233M-55+T&R require an external pullup resistor on the RST pin?

No, DS1233M-55+T&R integrates a 5 kΩ internal pullup resistor on the RST pin, eliminating the need for an external component in standard TTL/CMOS reset interfaces. This feature reduces BOM count and PCB area. However, if driving high-capacitance loads (>50 pF) or interfacing with non-standard logic families, an external pullup may still be recommended - but the DS1233M-55+T&R functions correctly without one under typical conditions.

Can DS1233M-55+T&R operate from a 3.3 V supply?

Yes, DS1233M-55+T&R supports supply voltages from 1.2 V to 5.5 V, and its internal reference remains stable across that range. However, its 4.5–4.75 V trip window is designed for 5 V systems. When used with a 3.3 V rail, the DS1233M-55+T&R will assert reset continuously because VCC never reaches the trip threshold - so it is not functionally appropriate for 3.3 V monitoring. For 3.3 V applications, DS1233M-3 (2.64–2.80 V trip) is the correct variant.

Is DS1233M-55+T&R pin-compatible with MC34064?

Yes, DS1233M-55+T&R is explicitly documented as pin-function compatible with MC33064, MC34064, MC33164, and MC34164 in TO-92 configuration. All share identical 3-pin layout (RST/VCC/GND), active-low open-drain RST output, and similar trip thresholds. No PCB modification is needed when substituting DS1233M-55+T&R into designs originally using MC34064, provided the 4.5–4.75 V trip matches system requirements.

What is the maximum sink current capability of the RST output in DS1233M-55+T&R?

The RST output of DS1233M-55+T&R can sink up to +8 mA while maintaining ≤0.4 V output voltage, per DC electrical characteristics. This is sufficient to drive standard CMOS and TTL reset inputs directly, including those of Motorola 68XXX and HC16 microprocessors. The DS1233M-55+T&R does not require a buffer stage for typical microcontroller reset pins, simplifying interface design and reducing component count.