Analog Devices Inc./Maxim Integrated MAX6306UK31D3+T

Overview

MAX6306UK31D3+T from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC for undervoltage conditions and provides a push/pull active-low reset output. It features a factory-set 3.08V ±2.5% reset threshold (per Table 1, UK31 = 3.08V nominal), 140ms minimum reset timeout (D3), manual reset input (MR), and guaranteed RESET validity down to VCC = 1V. It is used in multivoltage embedded systems requiring reliable power-on and brownout reset.

For engineers reviewing the MAX6306UK31D3+T datasheet, MAX6306UK31D3+T pinout, MAX6306UK31D3+T application, or MAX6306UK31D3+T equivalent, key selection considerations include its 3.08V VCC reset threshold tolerance, MR input timing (1.5µs min pulse width), 8µA supply current, immunity to fast VCC transients, and compatibility with 3.3V/5V dual-rail systems.

Technical Context

The MAX6306UK31D3+T uses an internal factory-trimmed resistor divider to monitor VCC against a precision reference, asserting reset when VCC falls below 3.08V ±2.5% over –40°C to +85°C. Its reset timeout is fixed at ≥140ms and is generated by an internal RC timer.

It includes a dedicated manual-reset input (MR) with internal 63.5kΩ pull-up, supporting TTL/CMOS logic levels and guaranteeing reset assertion during MR low and for the full timeout after MR release. The device operates from VCC = (VTH + 2.5%) to +5.5V - i.e., 3.16V to 5.5V - and maintains valid RESET output down to VCC = 1V.

Key Specifications

Pinout & Package

MAX6306UK31D3+T is housed in a lead-free 5-pin SOT23 package (outline U5+1, land pattern 90-0174), optimized for space-constrained PCB layouts and reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6306UK31D3+T, the D2 variant trades timeout duration for faster release, while TPS3808G33DBVR offers lower current and better accuracy but sacrifices MR functionality and adjustable secondary monitoring - making MAX6306UK31D3+T optimal for cost-sensitive, manually serviceable 3.3V/5V systems requiring robust transient immunity.

Availability

MAX6306UK31D3+T is available at Aetrix Electronics and suitable for industrial PLCs, portable medical devices, automotive body controllers, and network edge equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6306UK31D3+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 management, sensing, and interface applications, serving industrial, automotive, and communications markets.

The MAX6305–MAX6313 family was engineered specifically for multivoltage microprocessor supervision in space-constrained, noise-prone environments - delivering factory-programmable thresholds, manual reset, and transient-immune operation in SOT23 packaging.

FAQ

What is the exact factory-set reset threshold voltage for MAX6306UK31D3+T?

The MAX6306UK31D3+T has a factory-trimmed VCC reset threshold of 3.08V, with ±2.5% tolerance over –40°C to +85°C. This value is derived from Maxim's Table 1: "UK31" corresponds to nominal 3.08V (31 × 0.1V offset from 2.5V base). The actual threshold is guaranteed between 3.003V and 3.157V at room temperature and remains stable across temperature due to 40ppm/°C drift specification.

Does MAX6306UK31D3+T support monitoring of a second voltage rail?

Yes, MAX6306UK31D3+T supports secondary supply monitoring via its RST IN pin, which accepts an external resistor divider to set a custom undervoltage threshold referenced to the internal 1.23V bandgap. This allows independent supervision of a 5V, 12V, or other auxiliary rail alongside the primary 3.3V VCC monitoring - a capability confirmed in the Pin Description and Detailed Description sections of the datasheet.

What is the minimum VCC voltage required for MAX6306UK31D3+T to operate correctly?

MAX6306UK31D3+T requires VCC ≥ (VTH + 2.5%) = 3.16V to ensure proper internal biasing and comparator operation. Below this, the device may not assert reset reliably. However, once asserted, RESET remains valid down to VCC = 1V - meaning the output stays logically correct even as supply collapses, enabling safe shutdown sequencing.

Can the manual reset (MR) input of MAX6306UK31D3+T be driven by a microcontroller GPIO?

Yes, the MR input of MAX6306UK31D3+T is compatible with standard CMOS/TTL logic levels: VIH ≥ 0.7×VCC (for VTH < 4.0V) and VIL ≤ 0.3×VCC. With VCC = 3.3V, a GPIO high ≥ 2.31V and low ≤ 0.99V will reliably control reset. Its internal 63.5kΩ pull-up eliminates need for external resistors, and 1.5µs minimum pulse width accommodates typical MCU GPIO toggle timing.

Is MAX6306UK31D3+T RoHS-compliant and lead-free?

Yes, MAX6306UK31D3+T is RoHS-compliant and supplied in lead-free packaging, as indicated by the "+T" suffix per Maxim's Ordering Information. The "+" in the package code denotes RoHS status, and the device meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) requirements for standard reflow soldering up to +260°C peak temperature.