Analog Devices Inc./Maxim Integrated MAX6805US26D3+T

Overview

MAX6805US26D3+T from Maxim Integrated is a 4-pin SOT143 open-drain microprocessor supervisory circuit with 2.63V reset threshold, 100ms minimum reset timeout, and guaranteed operation down to V_CC = 1.0V. It monitors power supplies in 2.85V–5.0V systems, asserts active-low RESET during brownout or manual reset, and features debounced MR input and 4.0µA supply current. Used in portable battery-powered equipment for reliable µP power-up sequencing.

For engineers reviewing the MAX6805US26D3+T datasheet, MAX6805US26D3+T pinout, MAX6805US26D3+T application, or MAX6805US26D3+T equivalent, key selection criteria include open-drain output compatibility with bidirectional µP reset pins (e.g., Motorola 68HC11), factory-trimmed 2.63V threshold accuracy (±3% over –40°C to +125°C), and 100ms reset timeout stability across temperature.

Technical Context

The MAX6805US26D3+T implements a precision bandgap-based reset comparator with factory-trimmed 2.63V threshold and ±3% tolerance over –40°C to +125°C. Its open-drain RESET output requires an external pullup resistor and supports bidirectional reset interfaces without contention.

Reset assertion is triggered by V_CC falling below 2.63V or MR low pulse ≥1µs, with 100ms minimum timeout after V_CC recovery or MR deassertion. The device maintains valid RESET state down to V_CC = 1.0V but is not specified for validity at V_CC = 0 due to reduced sinking capability.

Key Specifications

Pinout & Package

Package: 4-pin SOT143 (U4-1 outline, land pattern 90-0183), RoHS-compliant lead-free (+T suffix), tape-and-reel only.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6805US26D3+T, MAX6315US26D3+T offers lower quiescent current in same footprint, while TPS3808G26DBVR adds watchdog capability at the cost of higher current and non-compatible packaging - both serve distinct design priorities beyond basic reset supervision.

Availability

MAX6805US26D3+T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, critical µP/µC power monitoring, intelligent instruments, and industrial controllers requiring stable component supply and long-term lifecycle support.

Supply support for MAX6805US26D3+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 industrial, automotive, and computing applications.

The MAX680x family delivers compact, low-power µP supervisory circuits with factory-trimmed thresholds and configurable timeouts for space-constrained embedded systems.

FAQ

What is the reset threshold voltage of the MAX6805US26D3+T and how accurate is it over temperature?

The MAX6805US26D3+T has a factory-trimmed reset threshold of 2.63V with ±1.8% accuracy at +25°C and ±3% over the full –40°C to +125°C operating range. This tolerance ensures reliable brownout detection across industrial temperature extremes without requiring external calibration components.

Does the MAX6805US26D3+T support manual reset, and what are the electrical requirements for the MR pin?

Yes, the MAX6805US26D3+T features a debounced manual-reset input (MR) requiring a logic-low pulse ≥1µs to assert reset. MR has an internal 20kΩ pullup resistor, so it may be left floating if unused. Valid logic levels are V_IL ≤ 0.3×V_CC and V_IH ≥ 0.7×V_CC, ensuring compatibility with standard CMOS drivers across its 1.0V–5.5V supply range.

What is the minimum supply voltage at which the MAX6805US26D3+T guarantees correct reset output behavior?

The MAX6805US26D3+T guarantees correct RESET/RESET output state down to V_CC = 1.0V over the full –40°C to +125°C temperature range. Below this voltage, reset assertion is not assured, and the device is not recommended for applications requiring valid reset down to 0V due to reduced open-drain sinking capability.

How does the open-drain output of the MAX6805US26D3+T differ from push/pull versions like MAX6804US26D3+T?

The MAX6805US26D3+T uses an open-drain RESET output requiring an external pullup resistor, enabling wired-OR configurations and safe interfacing with bidirectional µP reset pins (e.g., Motorola 68HC11). In contrast, the MAX6804US26D3+T provides push/pull drive capable of actively driving high and low without external components - a functional difference affecting system-level reset bus topology.

What are the absolute maximum ratings for the MAX6805US26D3+T's V_CC and RESET pins?

The MAX6805US26D3+T has an absolute maximum V_CC rating of –0.3V to +6V relative to GND. For the open-drain RESET pin, the absolute maximum voltage is –0.3V to +6V regardless of V_CC, allowing safe operation with pullup resistors tied to higher-voltage rails. Exceeding these limits risks permanent damage.