Analog Devices Inc./Maxim Integrated MAX6466UR21+T

Overview

MAX6466UR21+T from Maxim Integrated is a micropower supervisory circuit with active-low open-drain output, monitoring VCC for reset assertion when voltage falls below 2.100V (VTH−) and releasing after 150ms timeout once VCC exceeds 2.205V (VTH+). It draws only 1.0µA at 3.6V, features ±2.5% threshold accuracy over −40°C to +125°C, and operates in SOT23-3 package for battery-powered medical devices and portable electronics.

For engineers reviewing the MAX6466UR21+T datasheet, MAX6466UR21+T pinout, MAX6466UR21+T application, or MAX6466UR21+T equivalent, key selection criteria include guaranteed 150ms minimum reset timeout, 2.1V threshold with 5% hysteresis, open-drain compatibility with mixed-voltage logic, ultra-low supply current, and automotive-grade temperature range support.

Technical Context

The MAX6466UR21+T implements a precision bandgap reference and comparator with internally trimmed resistor networks to set fixed 2.100V lower trip threshold (VTH−) and 2.205V upper trip threshold (VTH+), delivering 5% hysteresis without external components. Its internal timeout circuit ensures reset remains asserted for ≥150ms after VCC crosses VTH+, preventing premature µP release during power-up instability.

This device belongs to the MAX6464–MAX6466 subfamily designated for µP reset supervision-not simple voltage detection-and uses an open-drain output stage requiring external pullup. It is functionally distinct from the MAX6461–MAX6463 voltage detectors due to its built-in timeout and absence of propagation delay specification.

Key Specifications

Pinout & Package

SOT23-3 package: 3-pin surface-mount, lead-free, RoHS-compliant, footprint compatible with industry-standard SOT-23 land pattern.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar µP reset supervision applications.

Compared with TPS3808G18DBVR and STM6315RWX6F, the MAX6466UR21+T uniquely combines exact 2.1V threshold, SOT23-3 open-drain compatibility, and 1.0µA supply current-making it optimal for battery-sensitive, multi-rail portable systems requiring precise reset timing without layout changes.

Availability

MAX6466UR21+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT endpoints, industrial handheld terminals, and automotive cabin sensors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6466UR21+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 and mixed-signal ICs for power, sensing, and interface applications, with emphasis on low-power, high-reliability solutions for demanding environments.

The MAX6461–MAX6466 family was developed specifically for ultra-low-power reset supervision in space- and energy-constrained systems such as portable medical equipment and automotive body electronics, prioritizing threshold accuracy, temperature stability, and minimal external component count.

FAQ

What is the exact threshold voltage of the MAX6466UR21+T?

The MAX6466UR21+T has a factory-trimmed lower trip threshold (VTH−) of 2.100V (typical) at +25°C, with guaranteed range of 2.048V to 2.153V over −40°C to +125°C. Its upper trip threshold (VTH+) is 2.205V (VTH− × 1.05), providing 5% hysteresis to prevent oscillation near the trip point. These values are confirmed in Table 1a and 1b of the official datasheet.

Does the MAX6466UR21+T require an external pullup resistor?

Yes, the MAX6466UR21+T features an active-low open-drain output and requires an external pullup resistor to establish a valid logic-high level when the output is not asserted. The pullup can connect to any voltage rail up to +6V, enabling level-shifting between different logic domains. Typical values range from 10kΩ to 100kΩ depending on rise-time and bus capacitance requirements.

What is the minimum reset timeout period of the MAX6466UR21+T?

The MAX6466UR21+T guarantees a minimum reset timeout period of 150ms, with typical value of 260ms and maximum of 430ms over temperature. This built-in timeout ensures the /RESET signal remains asserted long enough for microcontroller clock stabilization and firmware initialization, eliminating the need for external RC timing networks.

Can the MAX6466UR21+T operate down to 1.2V supply voltage?

Yes, the MAX6466UR21+T is fully specified to operate with VCC as low as +1.2V, per Absolute Maximum Ratings and Electrical Characteristics tables. However, output sinking capability degrades below 1.0V, so applications requiring valid output down to 0V should add a pull-down resistor to GND to ensure defined logic state during deep brownout conditions.

Is the MAX6466UR21+T pin-compatible with other devices in the MAX646x family?

The MAX6466UR21+T uses the SOT23-3 package and shares identical pinout (OUT, GND, VCC) with all MAX6461–MAX6466 variants in the same package variant (e.g., MAX6461UR21+T, MAX6464UR21+T). However, functional differences exist: MAX6466UR21+T provides 150ms timeout and open-drain output, whereas MAX6461UR21+T is a voltage detector without timeout, and MAX6464UR21+T offers push-pull active-low output.