Analog Devices Inc./Maxim Integrated MAX6309UK30D4

Overview

The MAX6309UK30D4 from Maxim Integrated is a 5-pin SOT23 programmable supervisory circuit that monitors VCC (factory-set threshold = 3.0V ±2.5%) and an external undervoltage input (RST IN), asserts active-low push/pull RESET during out-of-tolerance conditions, and provides manual reset (MR) with 1120ms minimum timeout. It draws only 8µA supply current and guarantees valid RESET down to VCC = 1V - used in multivoltage embedded systems requiring reliable power-on and brownout reset.

For engineers reviewing the MAX6309UK30D4 datasheet, MAX6309UK30D4 pinout, MAX6309UK30D4 application, or MAX6309UK30D4 equivalent, key selection considerations include its factory-programmed 3.0V VCC reset threshold, 1120ms reset timeout, push/pull active-low RESET output, MR input with internal 63.5kΩ pull-up, and immunity to fast VCC transients up to 100V/µs.

Technical Context

The MAX6309UK30D4 implements a dual-monitor architecture: one internal factory-trimmed voltage divider sets the primary VCC reset threshold at 3.0V, while a separate comparator monitors the RST IN pin against a 1.23V internal reference. Its push/pull RESET output actively drives low and high, eliminating external pull-up requirements.

It features guaranteed operation over -40°C to +85°C, includes built-in glitch rejection on MR (1.5µs min pulse width, 0.1µs noise immunity), and maintains reset assertion for the full 1120ms timeout after any monitored supply recovers - ensuring µP initialization completes before release.

Key Specifications

Pinout & Package

MAX6309UK30D4 is housed in a 5-pin SOT23 package (outline U5+1, land pattern 90-0174), measuring 2.9mm × 1.6mm × 1.1mm, suitable for space-constrained PCB layouts in portable and multilayer designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6309UK30D3 and TPS3808G30DBVR, the MAX6309UK30D4 uniquely combines factory-programmed 3.0V supervision, 1120ms timeout, RST IN capability, and push/pull RESET - making it optimal for industrial systems demanding robust, multi-input reset assurance without external components.

Availability

MAX6309UK30D4 is available at Aetrix Electronics and suitable for industrial PLCs, portable medical devices, automotive body electronics, smart energy meters, and multivoltage embedded controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6309UK30D4 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 industrial, communications, computing, and consumer applications - emphasizing reliability, integration, and low-power operation.

The MAX6305–MAX6313 family delivers programmable supervisory functions in minimal SOT23 packages, targeting space- and power-constrained embedded systems needing deterministic reset behavior under multirail and transient-prone conditions.

FAQ

What is the factory-programmed reset threshold voltage for MAX6309UK30D4?

The MAX6309UK30D4 has a factory-programmed VCC reset threshold of 3.0V, with tolerance of ±2.5% over the full operating temperature range (-40°C to +85°C). This value is set by an internal trimmed voltage divider and cannot be adjusted externally. The "30" in the part number explicitly denotes the 3.0V nominal threshold per Maxim's ordering convention.

Does MAX6309UK30D4 support manual reset functionality, and how is it implemented?

Yes, MAX6309UK30D4 includes a dedicated MR (manual reset) input on pin 4. It is internally pulled up to VCC with a 63.5kΩ resistor and responds to logic-low pulses ≥1.5µs duration. When asserted, it forces the active-low RESET output to remain low for the full 1120ms timeout period after MR returns high - enabling reliable user-initiated system restart without external circuitry.

What type of RESET output does MAX6309UK30D4 provide, and why does it matter?

MAX6309UK30D4 provides an active-low push/pull RESET output (pin 1), meaning it actively drives both low and high states. Unlike open-drain variants, it requires no external pull-up resistor - simplifying design, reducing component count, and ensuring strong logic-high drive (≥0.8×VCC) to interface directly with µP reset pins that demand defined high-level signaling during normal operation.

Can MAX6309UK30D4 monitor a second voltage rail besides VCC?

Yes, MAX6309UK30D4 includes an RST IN input (pin 3) that compares an external voltage to a precise 1.23V internal reference. By connecting a resistor divider from the secondary rail to RST IN and GND, designers can configure undervoltage supervision for a second supply - such as a 5V analog rail or isolated 12V bias - independent of the 3.0V VCC threshold.

What is the maximum supply voltage and transient immunity specification for MAX6309UK30D4?

MAX6309UK30D4 operates with VCC from 2.5V to 5.5V and withstands absolute maximum VCC of +6V. Its VCC input is immune to fast negative-going transients up to 100V/µs slew rate - a key feature documented in the Typical Operating Characteristics (TOC07) - preventing false resets caused by switching noise or load-dump events in industrial and automotive power systems.