Analog Devices Inc./Maxim Integrated MAX6309UK27D1-T

Overview

MAX6309UK27D1-T from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC (factory-set 2.7V reset threshold), an external undervoltage input (RST IN), and a manual-reset input (MR) to assert an active-low push/pull RESET signal. It features 8µA supply current, guaranteed RESET validity down to VCC = 1V, 1ms minimum reset timeout, and immunity to fast VCC transients. It is used in multivoltage embedded systems requiring reliable power-on and brownout reset control.

For engineers reviewing the MAX6309UK27D1-T datasheet, MAX6309UK27D1-T pinout, MAX6309UK27D1-T application, or MAX6309UK27D1-T equivalent, key selection criteria include its factory-trimmed 2.7V VCC threshold (±2.5% over temperature), MR input with internal 63.5kΩ pull-up, push/pull output capable of sinking 3.2mA at VCC > 4.25V, and operation across 0°C to +70°C.

Technical Context

The MAX6309UK27D1-T implements a dual-monitoring architecture: one path uses an internal factory-trimmed resistor divider to monitor VCC against a 2.7V threshold, while 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, or if MR is pulled low.

Its push/pull RESET output guarantees VOL ≤ 0.4V at ISINK = 3.2mA (VCC > 4.25V) and VOH ≥ 0.8 × VCC at ISOURCE = 500µA (VCC > 2.5V), enabling direct interface with 3.3V/5V µP reset inputs without external pull-ups. The 1ms minimum timeout (D1 variant) is factory-programmed and stable over temperature (±0.5% typical variation).

Key Specifications

Pinout & Package

MAX6309UK27D1-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 and TPS3808G125DBVR, the MAX6309UK27D1-T uniquely combines factory-set 2.7V VCC supervision, external RST IN capability, manual reset support, and minimal 1ms timeout in a 5-pin SOT23 - offering optimal flexibility for multivoltage embedded designs requiring fast, deterministic reset behavior.

Availability

MAX6309UK27D1-T is available at Aetrix Electronics and suitable for portable computers, embedded control systems, and multivoltage industrial controllers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6309UK27D1-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 systems, integrating precision reset thresholds, multiple input monitoring, and programmable timeouts into minimal 5-pin packages.

FAQ

What is the factory-set reset threshold voltage for MAX6309UK27D1-T?

The MAX6309UK27D1-T has a factory-trimmed VCC reset threshold of 2.7V nominal, with a tolerance of ±2.5% over the operating temperature range of 0°C to +70°C. This value is laser-trimmed during production and does not require external components or calibration. The "27" in the part number explicitly denotes the 2.7V threshold per Maxim's ordering convention.

Does MAX6309UK27D1-T support manual reset functionality?

Yes, MAX6309UK27D1-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 logic-compatible voltage levels (VIH = 0.7×VCC, VIL = 0.3×VCC). A low pulse ≥1.5µs forces RESET assertion for the full timeout period (1ms minimum), making it ideal for front-panel buttons or system-level reset commands.

What is the RESET output configuration of MAX6309UK27D1-T?

MAX6309UK27D1-T features an active-low push/pull RESET output on pin 1. Unlike open-drain variants, it actively drives both high and low states: VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC > 2.5V), and VOL ≤ 0.4V at ISINK = 3.2mA (VCC > 4.25V). This eliminates the need for an external pull-up resistor and ensures robust interfacing with standard µP reset inputs.

Can MAX6309UK27D1-T monitor a second voltage rail besides VCC?

Yes, MAX6309UK27D1-T includes an RST IN input (pin 3) that compares an externally applied voltage to an internal 1.23V reference. By connecting a resistor divider from the auxiliary rail (e.g., 5V, 12V, or 24V) to RST IN, designers can configure precise undervoltage detection for secondary supplies - enabling true multivoltage supervision in a single 5-pin device.

What is the minimum supply voltage at which MAX6309UK27D1-T guarantees valid RESET output?

MAX6309UK27D1-T guarantees valid RESET output down to VCC = 1V. Below this level, the push/pull driver strength degrades significantly. This specification ensures the reset signal remains asserted throughout deep brownout conditions, preventing erratic µP behavior during final stages of power loss - a critical requirement for data integrity in embedded systems.