Analog Devices Inc./Maxim Integrated MAX6306UK31D4+

Overview

MAX6306UK31D4+ from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC supply voltage and asserts an active-low push/pull reset signal when VCC falls below its factory-set 3.08V threshold (±2.5% over temperature), with a 1120ms minimum reset timeout period. It features manual-reset input (MR), guaranteed RESET validity down to VCC = 1V, and immunity to fast transients-ideal for reliable power-on reset in dual-voltage embedded systems.

For engineers reviewing the MAX6306UK31D4+ datasheet, MAX6306UK31D4+ pinout, MAX6306UK31D4+ application, or MAX6306UK31D4+ equivalent, key selection considerations include its 3.08V VCC reset threshold, 1120ms factory-programmed timeout, MR input compatibility with TTL/CMOS logic, guaranteed operation from -40°C to +85°C, and SOT23-5 package suitability for space-constrained PCB layouts.

Technical Context

The MAX6306UK31D4+ uses an internal factory-trimmed resistor divider to monitor VCC against a precision reference, enabling accurate undervoltage detection without external components. Its reset generator incorporates a temperature-stable timer circuit ensuring consistent 1120ms minimum timeout across -40°C to +85°C.

This device integrates a manual-reset input with internal 63.5kΩ pull-up, supporting direct connection to momentary switches or logic drivers. The push/pull RESET output sources/sinks current (VOH ≥ 0.8×VCC at ISOURCE = 500µA; VOL ≤ 0.3V at ISINK = 1.2mA), eliminating need for external pull-up resistors in most µP interface configurations.

Key Specifications

Pinout & Package

MAX6306UK31D4+ is housed in a lead-free 5-pin SOT23 package (outline U5+1), measuring 2.9mm × 1.6mm × 1.1mm, optimized for high-density PCB layouts and reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-monitoring reset applications.

Compared with MAX6306UK31D4+, the D3 variant reduces boot delay but sacrifices robustness against slow-ramping supplies, while TPS3808G33DBVR offers lower current and better threshold accuracy at the cost of functional flexibility and pin count.

Availability

MAX6306UK31D4+ is available at Aetrix Electronics and suitable for industrial control systems, portable medical devices, automotive infotainment units, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6306UK31D4+ 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, communications, and consumer applications.

The MAX6305–MAX6313 family was designed specifically for multivoltage microprocessor supervision in space-constrained, reliability-critical systems-emphasizing factory-programmability, transient immunity, and minimal external component count.

FAQ

What is the exact factory-set reset threshold voltage for MAX6306UK31D4+?

The MAX6306UK31D4+ has a nominal VCC reset threshold of 3.08V, with ±2.5% tolerance over the full operating temperature range (-40°C to +85°C). This value is factory-trimmed using an internal resistor divider and corresponds to the "31" suffix per Table 1 in the datasheet. The actual measured threshold for a given unit falls between 3.003V and 3.157V at room temperature.

Does MAX6306UK31D4+ require external components to function as a basic VCC supervisor?

No, MAX6306UK31D4+ requires zero external components for core VCC supervision. Its factory-programmed 3.08V threshold, 1120ms timeout, and push/pull RESET output eliminate the need for external resistors, capacitors, or pull-ups. Only optional features-such as RST IN monitoring or MR debouncing-require external parts like resistor dividers or 0.1µF bypass capacitors.

Can the manual-reset (MR) input of MAX6306UK31D4+ be driven directly by a microcontroller GPIO?

Yes, the MR input of MAX6306UK31D4+ accepts standard CMOS logic levels and features an internal 63.5kΩ pull-up resistor. A microcontroller GPIO configured as open-drain or push-pull can drive MR low to initiate reset. For 3.3V systems, VIH ≥ 0.7×VCC (≥2.1V) and VIL ≤ 0.3×VCC (≤1.0V) ensure reliable detection; no level-shifting is needed when VCC and MCU IO share the same supply.

What is the minimum VCC voltage at which MAX6306UK31D4+ guarantees valid RESET output behavior?

MAX6306UK31D4+ guarantees RESET output validity down to VCC = 1V. Below this, the push/pull driver's sourcing/sinking capability degrades significantly. The datasheet specifies VOL ≤ 0.3V at ISINK = 1.2mA and VOH ≥ 0.8×VCC at ISOURCE = 500µA for VCC > 2.5V; at VCC = 1V, RESET remains asserted but logic levels may not meet standard interface thresholds.

How does the 1120ms reset timeout (D4) of MAX6306UK31D4+ impact system boot timing?

The 1120ms minimum timeout of MAX6306UK31D4+ ensures the µP remains held in reset until all power domains-including slow-ramping LDOs, clock oscillators, and peripheral regulators-have fully stabilized. This prevents race conditions during initialization and is especially critical in systems with cascaded power supplies or high-capacitance loads. The timeout begins only after VCC exceeds 3.08V and remains above threshold for the entire duration.