Analog Devices Inc./Maxim Integrated MAX6314US31D3-T

Overview

MAX6314US31D3-T from Maxim Integrated is a low-power CMOS microprocessor supervisory circuit that monitors VCC supply voltage and asserts a bidirectional RESET signal when voltage falls below 3.08V or upon manual reset assertion. It features a factory-trimmed 3.08V reset threshold, 140ms minimum reset timeout period, ±1.8% threshold accuracy at +25°C, and operates in -40°C to +85°C industrial temperature range. It is used in portable/battery-powered equipment requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6314US31D3-T datasheet, MAX6314US31D3-T pinout, MAX6314US31D3-T application, or MAX6314US31D3-T equivalent, key selection criteria include its SOT143 package, bidirectional RESET output compatible with 68HC11-style µP reset I/O, 5µA quiescent current, immunity to short VCC transients, and absence of external component requirements for pullup or trimming.

Technical Context

The MAX6314US31D3-T implements a precision voltage-monitoring comparator with laser-trimmed internal resistive divider to set the 3.08V reset threshold, and an internal timer that guarantees RESET remains asserted for ≥140ms after VCC rises above threshold or MR deasserts. Its bidirectional RESET output combines a 4.7kΩ passive pullup resistor with a p-channel active pullup transistor enabled for 2µs during low-to-high transitions.

This architecture ensures fast rise time on shared reset buses-even with multiple devices and stray capacitance-while maintaining compatibility with µPs like the 68HC11 that detect reset source (internal vs. external) by sampling RESET state after two E-clock cycles. The MR input includes a 63kΩ internal pullup and supports debounced manual reset without external components.

Key Specifications

Pinout & Package

SOT143 (4-pin, 1.3mm × 2.9mm, 0.95mm height), surface-mount package rated for -40°C to +85°C operation. Lead-free packaging available (replace "-T" with "+T" in part number).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6314US31D3-T, MAX6315US31D3-T requires external pullup and lacks bidirectional support, while TPS3808G31DBVR omits MR and offers lower ICC but no µP-source discrimination-making MAX6314US31D3-T uniquely suited for 68HC11-compatible systems needing manual reset and glitch-immune brownout protection.

Availability

MAX6314US31D3-T is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC controllers, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6314US31D3-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 high-performance analog and mixed-signal semiconductor solutions for industrial, communications, computing, and consumer markets.

The MAX6314 family delivers precision, low-power µP supervisory circuits with factory-trimmed thresholds and bidirectional reset outputs-targeted specifically at systems using Motorola 68HC11 and compatible microcontrollers requiring source-aware reset behavior.

FAQ

What is the exact reset threshold voltage and accuracy of the MAX6314US31D3-T?

The MAX6314US31D3-T has a factory-trimmed nominal reset threshold of 3.08V, with ±1.8% accuracy at +25°C and ±2.5% over the full -40°C to +85°C temperature range. This value is laser-trimmed during manufacturing and verified per the Electrical Characteristics table in the official MAX6314 datasheet. The threshold is referenced to the VCC pin and applies to falling VCC conditions.

Does the MAX6314US31D3-T require external components for basic operation?

No, the MAX6314US31D3-T requires no external components for core supervision functionality. Its internal 4.7kΩ pullup resistor and p-channel active pullup eliminate the need for an external RESET pullup, while the MR input includes a 63kΩ internal pullup-enabling direct connection of a momentary switch to GND without debounce circuitry. A 0.1µF bypass capacitor on VCC is recommended but not mandatory.

How does the bidirectional RESET output of the MAX6314US31D3-T work with microcontrollers like the 68HC11?

The MAX6314US31D3-T's RESET output combines an n-channel pulldown, a 4.7kΩ passive pullup, and a p-channel active pullup enabled for 2µs during low-to-high transitions. This allows µPs such as the 68HC11 to assert RESET themselves and then sample its state after two E-clock cycles to distinguish internal vs. external reset sources-ensuring correct vector selection and state recovery without external timing components.

What is the minimum reset timeout period specified for the MAX6314US31D3-T?

The MAX6314US31D3-T is configured with a minimum reset timeout period (tRP) of 140ms, as indicated by the "D3" suffix in the part number. This duration is guaranteed over temperature and ensures sufficient hold time for µP initialization, memory settling, and peripheral configuration before release. The actual timeout may extend slightly due to process variation but will not fall below 140ms under any valid operating condition.

Can the MAX6314US31D3-T operate down to 1.0V supply voltage?

Yes, the MAX6314US31D3-T specifies an operating voltage range of 1.0V to 5.5V. It guarantees RESET remains a valid logic low for VCC > 1.0V (with ISINK = 80µA), enabling reliable supervision during deep brownout or battery depletion scenarios. Below 1.0V, RESET becomes high-impedance; for continuous validity to 0V, a 100kΩ external pull-down resistor on the RESET pin is recommended per the datasheet Application Information section.