Analog Devices Inc./Maxim Integrated MAX6805US46D3+T

Overview

The MAX6805US46D3+T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed to monitor 4.63V power supplies in embedded systems. It asserts reset when VCC falls below 4.63V (±3% over temperature) or upon manual reset assertion, with a guaranteed minimum 100ms timeout period and valid operation down to VCC = 1.0V. Used in portable equipment and critical µP power monitoring, it eliminates external components while providing glitch-immune reset generation.

For engineers reviewing the MAX6805US46D3+T datasheet, MAX6805US46D3+T pinout, MAX6805US46D3+T application, or MAX6805US46D3+T equivalent, key selection criteria include its 4.63V factory-trimmed threshold, 100ms min reset timeout, open-drain output for bidirectional µP reset pin interfacing, ultra-low 4µA supply current at 3V, and guaranteed functional operation to VCC = 1.0V.

Technical Context

This device implements a precision bandgap-based voltage comparator with hysteresis to detect VCC brownout conditions, coupled with a monostable timeout circuit triggered by either VCC recovery or MR deassertion. The internal 20kΩ MR pullup resistor enables direct switch-to-ground connection without external components.

The open-drain RESET output requires an external pullup resistor and supports wired-OR configurations-enabling compatibility with µPs like the Motorola 68HC11 that feature bidirectional reset pins. Reset assertion is immune to transients ≤30µs at 100mV overdrive, per the Maximum Transient Duration vs. Reset Comparator Overdrive curve.

Key Specifications

Pinout & Package

MAX6805US46D3+T is housed in a lead-free 4-pin SOT143 package (outline 21-0052), optimized for space-constrained PCB layouts and reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6804US46D3+T and TPS3808G33DBVR, the MAX6805US46D3+T uniquely combines 4.63V precision threshold, 100ms timeout, open-drain output for flexible reset bus architecture, and guaranteed 1.0V minimum VCC operation-making it optimal for brownout-critical, space-constrained, multi-device reset coordination scenarios.

Availability

MAX6805US46D3+T is available at Aetrix Electronics and suitable for portable equipment, industrial controllers, intelligent instrumentation, and critical µP/µC power monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6805US46D3+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, automotive, and computing applications.

The MAX6803/MAX6804/MAX6805 family delivers ultra-low-power, pin-compatible supervisory circuits targeting space- and power-sensitive embedded systems requiring reliable power-on and brownout reset functionality.

FAQ

What is the factory-trimmed reset threshold voltage for MAX6805US46D3+T?

The MAX6805US46D3+T has a factory-trimmed reset threshold of 4.63V, specified with ±1.8% tolerance at +25°C and ±3% over the full -40°C to +125°C operating temperature range. This value corresponds to the "46" suffix in the part number per Table 1 of the datasheet and is laser-trimmed during production to ensure accuracy without external components.

Does MAX6805US46D3+T require an external pullup resistor on the RESET pin?

Yes, MAX6805US46D3+T requires an external pullup resistor on the RESET pin because it features an open-drain output. The datasheet recommends a typical value of 100kΩ connected to the target µP's VCC rail or logic supply. This configuration enables wired-OR reset buses and compatibility with bidirectional reset pins such as those found on the Motorola 68HC11.

What is the minimum supply voltage at which MAX6805US46D3+T guarantees correct reset output behavior?

MAX6805US46D3+T guarantees correct RESET/RESET output behavior down to VCC = 1.0V over the full -40°C to +125°C temperature range. This is explicitly stated in the General Description and Electrical Characteristics sections, distinguishing it from the MAX6803/MAX6804 variants, which guarantee operation only to 0.7V.

How does the manual-reset input (MR) function on MAX6805US46D3+T?

The MR input on MAX6805US46D3+T is active-low and features an internal 20kΩ pullup resistor to VCC. Asserting MR low initiates reset immediately, and reset remains active for the full 100ms timeout period after MR returns high. If unused, MR may be left floating or tied to VCC; no external components are needed for basic operation.

What package type and RoHS status does MAX6805US46D3+T use?

MAX6805US46D3+T is supplied in a lead-free 4-pin SOT143 package (package code U4-1, outline 21-0052). The "+T" suffix explicitly denotes RoHS-compliant, lead-free construction per Maxim Integrated's packaging standards, and the device is shipped in tape-and-reel format only.