Analog Devices Inc./Maxim Integrated MAX6306UK31D4

Overview

MAX6306UK31D4 from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC and an external undervoltage input (RST IN), asserts active-low reset during brownout or power failure, and features factory-set 3.08V reset threshold and 1120ms minimum timeout. It draws only 8µA supply current, guarantees RESET validity down to VCC = 1V, and rejects fast transients-ideal for portable 3.3V/5V multivoltage systems.

For engineers reviewing the MAX6306UK31D4 datasheet, MAX6306UK31D4 pinout, MAX6306UK31D4 application, or MAX6306UK31D4 equivalent, key selection criteria include its dual-supply monitoring capability (VCC + RST IN), manual-reset input (MR), push/pull reset output structure, guaranteed operation over –40°C to +85°C, and immunity to sub-1µs VCC transients per typical operating characteristics.

Technical Context

The MAX6306UK31D4 implements a precision internal voltage divider to monitor VCC against a factory-trimmed 3.08V threshold (±2.5% over temperature), while simultaneously comparing an external voltage at RST IN to a 1.23V reference via resistor divider. Its reset generator enforces a fixed 1120ms minimum timeout after all monitored supplies return to regulation.

It integrates a 63.5kΩ internal pull-up on MR, supports TTL/CMOS logic levels on MR, and delivers a push/pull active-low RESET output capable of sinking 3.2mA at VCC > 4.25V. The device ignores transients shorter than ~1µs at full overdrive, as confirmed in Figure TOC7 of the datasheet.

Key Specifications

Pinout & Package

MAX6306UK31D4 is housed in a 5-pin SOT23 package (outline U5+1, land pattern 90-0174), measuring 2.9mm × 1.6mm × 1.1mm, RoHS-compliant, tape-and-reel packaged.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6306UK31D3 and TPS3808G33DBVR, the MAX6306UK31D4 uniquely combines dual-rail supervision (VCC + RST IN), manual reset, and long 1120ms timeout in a 5-pin SOT23 - making it optimal for robust multivoltage systems requiring extended reset hold and field-serviceability.

Availability

MAX6306UK31D4 is available at Aetrix Electronics and suitable for portable computers, industrial controllers, intelligent instruments, and multivoltage embedded systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6306UK31D4 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 management, sensing, and interface applications, serving industrial, computing, and communications markets.

The MAX6305–MAX6313 family was engineered specifically for multivoltage microprocessor supervision in space-constrained, battery-sensitive systems - delivering factory-programmed accuracy, ultra-low quiescent current, and transient-immune reset generation in SOT23 packaging.

FAQ

What is the factory-set reset threshold voltage for MAX6306UK31D4?

The MAX6306UK31D4 has a factory-trimmed VCC reset threshold of 3.08V nominal, with tolerance of ±2.5% over the full operating temperature range (–40°C to +85°C). This value is encoded in the "31" suffix per Table 1 of the datasheet, corresponding to the 3.08V entry (31 → 3.034V min / 3.080V typ / 3.126V max at +25°C).

Does MAX6306UK31D4 support manual reset functionality?

Yes, MAX6306UK31D4 includes a dedicated MR (manual reset) input on pin 4. Pulling MR low forces an immediate active-low RESET assertion, which persists for the full 1120ms timeout period after MR returns high. An internal 63.5kΩ pull-up resistor allows direct connection of a momentary switch to GND without external components.

What type of reset output does MAX6306UK31D4 provide?

MAX6306UK31D4 provides an active-low push/pull RESET output on pin 1. Unlike open-drain variants, this output actively drives both high and low states - eliminating the need for an external pull-up resistor and enabling direct interfacing with bidirectional µP reset pins such as those found on Motorola 68HC11 derivatives.

Can MAX6306UK31D4 monitor a second voltage rail besides VCC?

Yes, MAX6306UK31D4 monitors a second rail via the RST IN input (pin 3), which compares an externally divided voltage to an internal 1.23V reference. This allows supervision of auxiliary supplies like 3.3V, 2.5V, or 1.8V rails - independent of the 3.08V VCC threshold - enabling true dual-rail fault detection in multivoltage systems.

What is the minimum VCC voltage at which MAX6306UK31D4 guarantees valid RESET output?

MAX6306UK31D4 guarantees valid RESET output down to VCC = 1.0V, as specified in the Electrical Characteristics table. Below this level, push/pull drive strength degrades significantly; for applications requiring asserted RESET down to 0V, a 100kΩ pull-down resistor from RESET to GND is recommended per the Applications Information section.