Analog Devices Inc./Maxim Integrated MAX6309UK30D4-T

Overview

MAX6309UK30D4-T from Maxim Integrated is a 5-pin SOT23 programmable supervisory circuit that monitors VCC and an external undervoltage input (RST IN), asserts active-low push/pull RESET when either falls below its threshold, and provides 1120ms minimum reset timeout. It features factory-set 3.0V VCC reset threshold (±2.5% over temperature), 8µA supply current, and guaranteed RESET validity down to VCC = 1V. Used in multivoltage embedded systems for reliable power-on and brownout reset generation.

For engineers reviewing the MAX6309UK30D4-T datasheet, MAX6309UK30D4-T pinout, MAX6309UK30D4-T application, or MAX6309UK30D4-T equivalent, key selection criteria include its dual-supply monitoring capability (VCC + RST IN), manual-reset input with internal 63.5kΩ pull-up, immunity to fast VCC transients, and compatibility with 3.3V/5V microprocessor reset interfaces requiring stable active-low push/pull assertion.

Technical Context

The MAX6309UK30D4-T implements a dual-input supervisory architecture: one path monitors VCC via an internal factory-trimmed voltage divider set to 3.0V nominal threshold, while a second path accepts an external resistor-divider–programmed undervoltage signal at RST IN (1.23V reference). Both inputs feed independent comparators with built-in hysteresis (2.5mV on RST IN).

Reset assertion is synchronized by an internal timer that enforces a minimum 1120ms timeout after all monitored supplies return above threshold; the manual-reset input (MR) forces reset for its duration plus full tRP. The push/pull RESET output sources/sinks current (VOH = 0.8×VCC, VOL = 0.3V), eliminating need for external pull-up resistors in most µP interfaces.

Key Specifications

Pinout & Package

MAX6309UK30D4-T is housed in a 5-pin SOT23 package (outline U5+1, land pattern 90-0174), measuring 2.9mm × 1.6mm × 1.1mm, RoHS-compliant with lead-free finish (suffix "+T" denotes lead-free; "-T" is standard leaded).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6312UK30D4-T, the MAX6309UK30D4-T omits overvoltage detection but retains identical VCC/RST IN accuracy and MR functionality - reducing component count where OVRST IN is unnecessary. Versus TPS3808G30DBVT, it adds RST IN and MR while delivering longer timeout and lower quiescent current, at the cost of slightly larger footprint.

Availability

MAX6309UK30D4-T is available at Aetrix Electronics and suitable for industrial PLCs, medical patient monitors, automotive body control modules, and network router power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6309UK30D4-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 and mixed-signal ICs for power, sensing, interface, and reliability-critical applications.

The MAX6305–MAX6313 family delivers highly integrated, low-power supervisory circuits targeting multivoltage embedded systems where robust reset generation under brownout, transient, and manual-recovery conditions is essential.

FAQ

What is the factory-set VCC reset threshold for MAX6309UK30D4-T?

The MAX6309UK30D4-T has a factory-trimmed VCC reset threshold of 3.0V nominal, with ±2.5% tolerance over the full operating temperature range (-40°C to +85°C). This value is encoded in the "30" segment of the part number and verified per Electrical Characteristics table in the datasheet. The MAX6309UK30D4-T uses an internal resistor divider to achieve this precise threshold without external components.

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

Yes, the MAX6309UK30D4-T includes a dedicated MR (manual-reset) input on pin 4. It is active-low, internally pulled up to VCC with 63.5kΩ, and requires a logic-low pulse ≥1.5µs to assert reset. After MR returns high, the MAX6309UK30D4-T maintains RESET active for the full 1120ms timeout period. This enables hardware reset buttons or external logic control without additional biasing components.

What is the function of the RST IN pin on MAX6309UK30D4-T?

The RST IN pin (pin 3) on the MAX6309UK30D4-T is an adjustable undervoltage reset input referenced to a precise 1.23V internal comparator threshold. When used with an external resistor divider, it monitors secondary power rails (e.g., 1.8V, 2.5V) and asserts RESET if the divided voltage falls below 1.23V. This enables dual-rail supervision alongside the factory-set 3.0V VCC monitor in the MAX6309UK30D4-T.

Is MAX6309UK30D4-T compatible with 3.3V microprocessor reset inputs?

Yes, the MAX6309UK30D4-T's push/pull RESET output is fully compatible with 3.3V µP reset inputs. At VCC = 3.3V, it guarantees VOH ≥ 0.8×VCC (≥2.64V) and VOL ≤ 0.3V when sinking 500µA, meeting standard 3.3V CMOS logic thresholds. Its active-low assertion and 1120ms timeout align with common µP reset timing requirements, and no external pull-up is needed due to its push/pull structure.

What package type and environmental compliance does MAX6309UK30D4-T use?

The MAX6309UK30D4-T is supplied in a 5-pin SOT23 package (outline U5+1) with dimensions 2.9mm × 1.6mm × 1.1mm. It is available in both leaded ("-T") and lead-free ("+T") variants per RoHS Directive 2011/65/EU. The "-T" suffix in MAX6309UK30D4-T indicates standard leaded packaging; lead-free ordering requires substituting "+T" per Maxim's ordering guidelines.