Analog Devices Inc./Maxim Integrated MAX6844UKD3+T

Overview

The MAX6844UKD3+T from Maxim Integrated is an ultra-low-voltage microprocessor supervisory circuit with adjustable reset threshold, active-high push-pull RESET output, 210ms reset timeout, ±2.5% threshold accuracy over temperature, and 5.7µA typical supply current - designed for reliable power monitoring in portable/battery-powered systems operating down to 0.75V VCC.

For engineers reviewing the MAX6844UKD3+T datasheet, MAX6844UKD3+T pinout, MAX6844UKD3+T application, or MAX6844UKD3+T equivalent, this page delivers verified functional identity, SOT23-5 package mapping, RESET IN–based threshold configuration, manual reset integration, and design-critical timing and voltage specifications - all confirmed from Maxim's official datasheet Rev 2 (12/05).

Technical Context

The MAX6844UKD3+T implements a precision comparator architecture that monitors the differential voltage between VCC and the RESET IN pin, triggering reset when RESET IN falls below 187.4mV (referenced to VCC). Its internal 20kΩ MR pullup enables direct switch-to-ground manual reset without external components.

Reset assertion is synchronized to both VCC decay and RESET IN threshold crossing, with fixed 210ms timeout (D3 option) guaranteed across –40°C to +85°C. The active-high push-pull RESET output drives high during reset and low otherwise, delivering valid logic levels down to VCC = 0.75V with VOH ≥ 0.8×VCC and VOL ≤ 0.2×VCC.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, tape-and-reel), footprint-compatible with industry-standard SOT-23 layout; thermal resistance θ_JA = 140°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6843UKD3+T, the MAX6844UKD3+T provides native active-high reset signaling - simplifying interface to modern MCUs with non-inverting reset pins - while retaining identical adjustability, accuracy, and low-power performance. Against TPS3123K33DBVR, it trades lower ICC for essential sub-1V adaptability and precision threshold control.

Availability

The MAX6844UKD3+T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered IoT edge nodes, industrial handheld controllers, and telecom baseband modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6844UKD3+T 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 demanding industrial, computing, and communications applications.

The MAX6841–MAX6845 family was engineered specifically for ultra-low-voltage microprocessor supervision in space-constrained, battery-sensitive systems - delivering factory-trimmed or user-adjustable reset thresholds with minimal external components.

FAQ

What is the exact reset timeout period of the MAX6844UKD3+T?

The MAX6844UKD3+T has a fixed reset timeout period of 210ms (typical), corresponding to the D3 suffix in its part number. This value is guaranteed across the full operating temperature range (–40°C to +85°C) and remains stable regardless of VCC level within the 0.75V–1.8V range. The timeout begins when VCC or RESET IN rises above its respective threshold and ends when the active-high RESET output transitions low.

How do I configure the reset threshold for the MAX6844UKD3+T?

The MAX6844UKD3+T uses its RESET IN pin to accept an externally derived threshold voltage referenced to VCC. To set a target VCC threshold (e.g., 0.9V), connect a resistor divider between VCC and GND, tapping the midpoint to RESET IN. With VRSTIN = 187.4mV (typ), use R1 = R2 × (VCC_TH / 187.4mV − 1); for 0.9V, R2 = 100kΩ yields R1 ≈ 380kΩ. The MAX6844UKD3+T monitors the differential, not absolute voltage.

Does the MAX6844UKD3+T support operation below 1.0V?

Yes - the MAX6844UKD3+T operates from VCC = 0.75V to 1.8V and guarantees valid reset functionality down to 0.75V. Its active-high push-pull RESET output maintains VOH ≥ 0.8×VCC and VOL ≤ 0.2×VCC across this range, enabling reliable interfacing with sub-1V logic families. The 5.7µA supply current at 0.9V further confirms its suitability for ultra-low-voltage battery systems.

Can the MAX6844UKD3+T replace a fixed-threshold supervisor like the MAX6841?

No - the MAX6844UKD3+T is not a drop-in replacement for fixed-threshold parts like the MAX6841 because it lacks factory-trimmed VCC monitoring and instead requires external resistor configuration via RESET IN. While both share SOT23-5 packaging and MR functionality, the MAX6844UKD3+T's circuit role is adjustable supervision, not voltage detection. Substitution would require redesigning the threshold network and verifying timing compatibility.

What is the maximum allowable leakage current at the RESET IN pin of the MAX6844UKD3+T?

The MAX6844UKD3+T specifies RESET IN leakage current (IRSTIN) as ±25nA over temperature (–40°C to +85°C). This ultra-low leakage enables use of high-value resistors (e.g., 1MΩ) in the threshold divider network, minimizing current draw from the monitored rail - a critical advantage in multi-year battery applications. The value is measured with VCC > 0.788V and is independent of external loading.