Analog Devices Inc./Maxim Integrated DS1233M-3+

Overview

DS1233M-3+ from Maxim Integrated (now Analog Devices) is a precision voltage-monitoring microprocessor supervisory circuit that asserts an active-low reset signal during power supply undervoltage or failure. It features a 2.72 V typical VCC trip point, 350 ms reset timeout, and operates from -40°C to +85°C in TO-92 or 8-pin SOIC packages-used in embedded microcontroller systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the DS1233M-3+ datasheet, DS1233M-3+ pinout, DS1233M-3+ application, or DS1233M-3+ equivalent, key selection criteria include its 2.64–2.80 V trip window, internal 5 kΩ pullup, RST timing consistency across temperature, and compatibility with Motorola 68XXX/HC16 families and MC33064-series devices.

Technical Context

The DS1233M-3+ integrates a temperature-compensated voltage reference and comparator to monitor VCC against a fixed 2.72 V threshold. When VCC drops below VLTL (2.48 V) or rises above VHTL (3.14 V), the device triggers RST assertion with ≤10 µs propagation delay (tRPD).

Upon power-up, it holds RST active for 200–500 ms (typ. 350 ms) to ensure system stabilization; the internal 5 kΩ pullup eliminates external components for open-drain reset signaling to compatible microprocessors.

Key Specifications

Pinout & Package

DS1233M-3+ is available in TO-92 (3-pin) and 8-pin SOIC packages. The TO-92 variant uses pins 1=RST, 2=VCC, 3=GND; the SOIC variant assigns pins 1=RST, 2=VCC, 3=NC, 4=GND, with pins 5–8 unconnected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-monitoring reset applications.

Compared with MAX6326–UR31T+ and TPS3808G33DBVR, the DS1233M-3+ delivers guaranteed 350 ms reset hold and integrated pullup in a legacy-compatible footprint-making it optimal for cost-sensitive, volume industrial designs requiring proven reliability without redesign.

Availability

DS1233M-3+ is available at Aetrix Electronics and suitable for industrial PLC controllers, medical handheld diagnostics, automotive body control modules, and smart energy meters requiring stable component supply and long-lifecycle support.

Supply support for DS1233M-3+ 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 (via acquisition of Maxim Integrated) designs high-performance analog, mixed-signal, and power management ICs for precision sensing, power integrity, and reliable system supervision.

The DS1233M-3+ belongs to Maxim's EconoReset™ family-engineered for cost-effective, pin-compatible replacement of legacy reset supervisors in space- and BOM-constrained microcontroller systems.

FAQ

What is the exact voltage trip point range for DS1233M-3+?

The DS1233M-3+ has a guaranteed VCC trip point range of 2.64 V to 2.80 V at +25°C, with temperature-compensated performance across -40°C to +85°C. This window is specifically calibrated for 3.3 V supply monitoring, where it detects undervoltage conditions before system instability occurs. The DS1233M-3+ datasheet specifies VLTL = 2.48 V and VHTL = 3.14 V as the hysteresis band edges. DS1233M-3+ maintains this specification without external trimming.

Does DS1233M-3+ require an external pullup resistor on the RST pin?

No, DS1233M-3+ includes an internal 3.75–6.50 kΩ pullup resistor on the RST pin, eliminating the need for external components in most standard microcontroller interfaces. However, if the target MCU reset input has unusually high leakage or capacitive loading, an external pullup may still be recommended-verified per actual board-level testing. DS1233M-3+'s internal pullup is sufficient for direct connection to Motorola 68XXX, HC16, and compatible processors.

Is DS1233M-3+ pin-compatible with MC33064-series devices?

Yes, DS1233M-3+ is explicitly pin-function compatible with MC33064, MC34064, MC33164, and MC34164 per Maxim's datasheet. In TO-92, all share identical 1=RST, 2=VCC, 3=GND assignments; in SOIC, DS1233M-3+ mirrors the same active pin positions (1=RST, 2=VCC, 4=GND), with NC pins placed consistently. DS1233M-3+ can serve as a direct replacement without PCB modification.

What is the reset timeout duration of DS1233M-3+ and how is it controlled?

The DS1233M-3+ provides a factory-trimmed reset timeout of 200–500 ms, with a typical value of 350 ms after VCC returns to tolerance. This timing is internally generated and does not rely on external RC networks. It ensures sufficient stabilization time for both the 3.3 V power rail and connected microprocessor clock domains. DS1233M-3+ guarantees this behavior across full temperature and voltage ranges without user adjustment.

Can DS1233M-3+ operate with supply voltages below 3.0 V?

Yes, DS1233M-3+ supports VCC from 1.2 V to 5.5 V and remains functional down to 1.2 V, though its 2.64–2.80 V trip point means it will assert reset continuously below ~2.6 V. It is commonly used in 3.3 V systems but retains monitoring capability in low-voltage microcontroller domains (e.g., 1.8 V logic with 3.3 V I/O). DS1233M-3+'s operating current is only 50 µA, making it viable for ultra-low-power designs.