Analog Devices Inc./Maxim Integrated MAX6306UK29D4+

Overview

The MAX6306UK29D4+ from Maxim Integrated is a 5-pin SOT23 programmable supervisory circuit that monitors VCC and one external undervoltage input (RST IN), asserts an active-low push/pull RESET output, features a manual-reset input (MR), and provides factory-set 2.9V reset threshold with 1120ms minimum timeout. It draws only 8µA supply current and guarantees valid RESET down to VCC = 1V - ideal for battery-powered microcontroller systems requiring reliable power-on and brownout reset.

For engineers reviewing the MAX6306UK29D4+ datasheet, MAX6306UK29D4+ pinout, MAX6306UK29D4+ application, or MAX6306UK29D4+ equivalent, this page delivers verified technical context, precise pin functionality, real-world use cases in multivoltage embedded systems, and two confirmed alternative parts with documented functional and timing differences.

Technical Context

The MAX6306UK29D4+ implements a precision internal voltage divider to monitor VCC against a factory-trimmed 2.9V threshold (±2.5% over –40°C to +85°C), while simultaneously comparing an external voltage at RST IN to a 1.23V internal reference. Its reset assertion logic combines both inputs: RESET activates if either VCC falls below 2.9V or RST IN drops below its programmed threshold.

It integrates a manual-reset input (MR) with 63.5kΩ internal pull-up, guaranteed 1.5µs minimum pulse width immunity, and a fixed 1120ms (min) reset timeout after all monitored supplies recover. The push/pull RESET output sinks ≥3.2mA at VCC > 4.25V and sources ≥800µA, ensuring robust drive into µP reset pins without external pull-ups.

Key Specifications

Pinout & Package

MAX6306UK29D4+ is housed in a lead-free 5-pin SOT23 package (outline U5+1), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6306UK29D4+, the MAX6306UK29D3+ offers identical supervision accuracy and interface but significantly shorter reset hold time, while the TPS3808G33DBVR trades multifunction capability for lower current and simpler integration in basic 3.3V-only designs.

Availability

MAX6306UK29D4+ is available at Aetrix Electronics and suitable for portable computers, embedded control systems, and intelligent instruments requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX6306UK29D4+ 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 in industrial, computing, and communications systems.

The MAX6305–MAX6313 family was engineered specifically for multivoltage microprocessor supervision - combining factory-trimmed thresholds, adjustable inputs, manual reset, and robust transient immunity in minimal SOT23 packaging.

FAQ

What is the exact reset threshold voltage for MAX6306UK29D4+ and how tightly is it specified?

The MAX6306UK29D4+ has a factory-trimmed nominal VCC reset threshold of 2.9V, with a tolerance of ±2.5% over the full operating temperature range of –40°C to +85°C. This specification is guaranteed by production testing per the datasheet's Electrical Characteristics table, and the device uses an internal trimmed voltage divider - no external components affect this threshold. The 2.9V value corresponds to entry "29" in Table 1 of the MAX6305–MAX6313 datasheet.

Does MAX6306UK29D4+ support monitoring of a second voltage rail beyond VCC?

Yes, the MAX6306UK29D4+ includes a dedicated RST IN pin that compares an external voltage to a precise 1.23V internal reference. By connecting a resistor divider from the secondary rail (e.g., 1.8V or 2.5V) to RST IN, users can program undervoltage detection for that rail independently of the 2.9V VCC threshold. The input leakage is ≤±25nA, enabling megohm-level divider resistors with minimal error.

What is the function of the MR pin on MAX6306UK29D4+ and how should it be interfaced?

The MR pin on MAX6306UK29D4+ is an active-low manual-reset input with an internal 63.5kΩ pull-up resistor to VCC. Driving MR low forces RESET assertion for the full timeout period (1120ms min) after MR returns high. It accepts TTL logic in 5V systems and CMOS levels in 3V systems. For front-panel use, connect a normally open momentary switch from MR to GND; no external debounce is needed due to built-in 0.1µs glitch rejection.

How does the RESET output of MAX6306UK29D4+ differ from open-drain alternatives?

The MAX6306UK29D4+ features an active-low push/pull RESET output - meaning it actively drives both low (sinking ≥3.2mA at VCC > 4.25V) and high (sourcing ≥800µA). Unlike open-drain supervisors, it requires no external pull-up resistor, simplifies PCB layout, and ensures fast, robust transitions into bidirectional µP reset pins (e.g., Motorola 68HC11). This architecture also maintains defined logic states during VCC brownout down to 1V.

Is MAX6306UK29D4+ compatible with lead-free PCB assembly processes?

Yes, the "+" suffix in MAX6306UK29D4+ explicitly denotes RoHS-compliant, lead-free packaging. The device is qualified for standard Pb-free reflow profiles with a peak soldering temperature of +260°C, per Maxim's package documentation. The SOT23-5 outline (U5+1) is identical to its leaded counterpart - only the finish differs - ensuring drop-in compatibility in existing layouts and manufacturing lines.