Analog Devices Inc./Maxim Integrated MAX6309UK31D3-T

Overview

MAX6309UK31D3-T from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC (factory-set at 3.08V ±2.5%), an external undervoltage input (RST IN), and a manual reset (MR) to assert an active-low push/pull RESET output. It guarantees valid reset assertion down to VCC = 1V, features 140ms minimum reset timeout, and draws only 8µA supply current - ideal for battery-powered multivoltage systems requiring reliable brownout protection.

For engineers reviewing the MAX6309UK31D3-T datasheet, MAX6309UK31D3-T pinout, MAX6309UK31D3-T application, or MAX6309UK31D3-T equivalent, key selection criteria include its factory-trimmed 3.08V VCC threshold, immunity to fast transients (<100ns), guaranteed operation over 0°C to +70°C, and compatibility with 3.3V/5V mixed-rail embedded controllers.

Technical Context

The MAX6309UK31D3-T implements a dual-monitoring architecture: an internal factory-trimmed resistor divider sets the primary VCC reset threshold at 3.08V, while a dedicated RST IN pin accepts externally scaled undervoltage signals referenced to a precise 1.23V internal comparator threshold. Its push/pull RESET output drives both high and low without external pull-up, ensuring deterministic logic levels across full VCC range (1.0V–5.5V).

Reset assertion is triggered when either VCC falls below 3.08V (±2.5% over temperature) or RST IN drops below 1.23V (±50mV hysteresis), with MR providing asynchronous override. The internal timer enforces a fixed 140ms minimum timeout after all monitored inputs return to valid states - a value factory-programmed via the "D3" suffix and verified over -40°C to +85°C.

Key Specifications

Pinout & Package

MAX6309UK31D3-T is housed in a 5-pin SOT23 package (outline U5+1, land pattern 90-0174), optimized for space-constrained PCB layouts in portable electronics. Pin 1 is RESET (active-low push/pull), Pin 2 is GND, Pin 3 is RST IN (undervoltage monitor input), Pin 4 is MR (manual reset input), and Pin 5 is VCC (supply input and primary monitor rail).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6309UK31D3-T, the MAX6309UK30D3-T offers a lower nominal threshold for tighter brownout response, while the TPS3808G33DBVR trades supervision flexibility for lower quiescent current and simplified single-rail use - neither is pin-compatible nor functionally equivalent without schematic revision.

Availability

MAX6309UK31D3-T is available at Aetrix Electronics and suitable for industrial PLCs, medical patient monitors, automotive infotainment head units, and smart energy meters requiring stable component supply across extended production lifecycles.

Supply support for MAX6309UK31D3-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 portable and embedded systems - delivering precision reset thresholds, transient immunity, and minimal external component count in ultra-small packages.

FAQ

What is the factory-programmed VCC reset threshold for MAX6309UK31D3-T?

The MAX6309UK31D3-T has a factory-programmed VCC reset threshold of 3.08V, with ±2.5% tolerance over the 0°C to +70°C operating temperature range. This value is laser-trimmed during manufacturing and corresponds to the "31" in the part number per Table 1 of the datasheet. The MAX6309UK31D3-T uses this threshold to detect brownout conditions on the primary 3.3V supply rail.

Does MAX6309UK31D3-T support manual reset functionality?

Yes, the MAX6309UK31D3-T includes a dedicated MR (manual reset) input on Pin 4. A logic-low pulse ≥1.5µs asserts RESET for the full 140ms timeout period. The pin features a 63.5kΩ internal pull-up resistor, enabling direct connection to a momentary switch without external components. The MAX6309UK31D3-T guarantees MR operation across its full VCC range (1.0V–5.5V).

What is the reset timeout period for MAX6309UK31D3-T?

The MAX6309UK31D3-T has a factory-programmed reset timeout period of 140ms minimum, indicated by the "D3" suffix in the part number. This timeout is enforced after all monitored inputs (VCC and RST IN) return above their respective thresholds, ensuring the microprocessor completes power-up initialization. The MAX6309UK31D3-T maintains this timing specification across temperature and supply voltage variations.

Can MAX6309UK31D3-T monitor a secondary voltage rail?

Yes, the MAX6309UK31D3-T includes an RST IN pin (Pin 3) that accepts an externally scaled voltage via resistor divider to monitor a secondary rail (e.g., 1.8V or 2.5V). The internal comparator triggers reset when RST IN falls below 1.23V ±50mV. This dual-monitoring capability makes the MAX6309UK31D3-T suitable for systems with multiple independent power domains.

What package type and RoHS status does MAX6309UK31D3-T use?

The MAX6309UK31D3-T is supplied in a lead-free 5-pin SOT23 package (package code U5+1), compliant with RoHS Directive 2011/65/EU. The "-T" suffix denotes tape-and-reel packaging; leaded versions use "-T" without the "+", but the MAX6309UK31D3-T specifically ships in lead-free form. Its compact 2.9mm × 1.6mm footprint supports high-density PCB layouts in portable equipment.