Analog Devices Inc./Maxim Integrated MAX6309UK27D2-T

Overview

The MAX6309UK27D2-T from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC (factory-set 2.7V reset threshold) and an external undervoltage input (RST IN), while providing manual reset capability and push/pull active-low RESET output. It asserts system reset during power-up, brownout, or manual trigger events, with guaranteed operation down to VCC = 1V, 8µA supply current, and 20ms minimum reset timeout. It is used in portable computers and multivoltage embedded systems requiring reliable power monitoring.

For engineers reviewing the MAX6309UK27D2-T datasheet, MAX6309UK27D2-T pinout, MAX6309UK27D2-T application, or MAX6309UK27D2-T equivalent, key selection considerations include its factory-trimmed 2.7V VCC threshold (±2.5% over temperature), 20ms reset timeout, manual-reset input with internal 63.5kΩ pull-up, push/pull RESET output capable of sinking 3.2mA at VCC > 4.25V, and immunity to fast VCC transients.

Technical Context

The MAX6309UK27D2-T implements a dual-monitoring architecture: one path uses an internal factory-trimmed resistor divider to monitor VCC against a 2.7V threshold, and a second path compares an external voltage applied to RST IN against a 1.23V internal reference. Reset assertion occurs if either monitored voltage falls below its respective threshold, and the internal timer holds RESET active for ≥20ms after all inputs return to regulation.

Its push/pull RESET output drives low actively (VOL ≤ 0.4V at ISINK = 3.2mA, VCC > 4.25V) and high actively (VOH ≥ 0.8 × VCC at ISOURCE = 500µA, VCC > 2.5V), eliminating need for external pull-up resistors. The MR input features TTL/CMOS-compatible logic thresholds, 1.5µs minimum pulse width, and internal ESD protection - but requires MR supply to match VCC to avoid violating absolute maximum ratings.

Key Specifications

Pinout & Package

MAX6309UK27D2-T is housed in a 5-pin SOT23 package (outline U5+1, land pattern 90-0174), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and RoHS-compliant lead-free finish (indicated by "+T" suffix; "-T" denotes standard leaded).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6309UK27D2-T, the MAX6309UK27D3-T offers identical functionality with extended reset timing, while the TPS3808G125DBVR trades dual-input flexibility and higher drive strength for lower supply current and simpler single-threshold operation - making it unsuitable as a drop-in replacement in multivoltage designs.

Availability

MAX6309UK27D2-T is available at Aetrix Electronics and suitable for portable computers, industrial controllers, and battery-powered instruments requiring stable component supply with guaranteed long-term availability and consistent parametric performance.

Supply support for MAX6309UK27D2-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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, computing, and communications markets.

The MAX6305–MAX6313 family was designed specifically for multivoltage microprocessor supervision in space-constrained, low-power systems - delivering precision reset thresholds, transient immunity, and integrated manual reset in miniature SOT23 packages.

FAQ

What is the factory-set VCC reset threshold for MAX6309UK27D2-T?

The MAX6309UK27D2-T has a factory-trimmed VCC reset threshold of 2.7V, with ±2.5% tolerance over the full operating temperature range (-40°C to +85°C). This value is encoded in the "27" portion of the part number and is implemented using an internal precision resistor divider - no external components are required to set or calibrate this threshold. The MAX6309UK27D2-T maintains this accuracy without user adjustment.

Does MAX6309UK27D2-T support manual reset functionality?

Yes, the MAX6309UK27D2-T includes a dedicated MR (manual reset) input on pin 4. It is active-low, features an internal 63.5kΩ pull-up resistor, and accepts TTL- or CMOS-level logic signals. A low pulse ≥1.5µs forces RESET assertion for the full timeout period (20ms minimum) after MR returns high. The MAX6309UK27D2-T does not require external pull-up or debounce circuitry for basic operation.

What type of RESET output does MAX6309UK27D2-T provide?

The MAX6309UK27D2-T provides a push/pull active-low RESET output on pin 1. Unlike open-drain variants, it actively drives both high and low states - sourcing up to 500µA at VCC > 2.5V and sinking up to 3.2mA at VCC > 4.25V. This eliminates the need for an external pull-up resistor and ensures robust logic-level definition across its operating range, including down to VCC = 1V.

Can MAX6309UK27D2-T monitor a second voltage rail besides VCC?

Yes, the MAX6309UK27D2-T monitors a second voltage via the RST IN input (pin 3), which compares an external voltage to a precise 1.23V internal reference. By connecting a resistor divider from the target rail (e.g., 3.3V or 5V) to RST IN and GND, users can program an additional undervoltage detection point. This dual-monitoring capability is confirmed in the device's functional diagram and pin description for MAX6309UK27D2-T.

What is the minimum reset timeout period for MAX6309UK27D2-T?

The MAX6309UK27D2-T has a factory-programmed minimum reset timeout period of 20ms, indicated by the "D2" suffix in the part number. This value is guaranteed over temperature and supply voltage, and defines the minimum duration RESET remains asserted after all monitored voltages return to regulation. The MAX6309UK27D2-T uses an internal oscillator-based timer - no external capacitor is needed to set or adjust this timing.