Analog Devices Inc./Maxim Integrated MAX6312UK29D3+

Overview

MAX6312UK29D3+ from Maxim Integrated is a precision 5-pin SOT23 programmable reset IC designed to monitor VCC and an external undervoltage input (RST IN) while providing manual-reset capability. It features a factory-set 2.9V ±2.5% VCC reset threshold, 140ms (min) reset timeout, active-high push/pull RESET output, and operates from VCC = (VTH + 2.5%) to +5.5V - ideal for dual-supply 3.3V/5V embedded control systems requiring reliable brownout protection.

For engineers reviewing the MAX6312UK29D3+ datasheet, MAX6312UK29D3+ pinout, MAX6312UK29D3+ application, or MAX6312UK29D3+ equivalent, key selection considerations include its guaranteed RESET validity down to VCC = 1.0V, immunity to fast VCC transients (<100ns), 8µA supply current at +25°C, manual-reset input with internal 63.5kΩ pull-up, and compatibility with TTL/CMOS logic levels in mixed-voltage designs.

Technical Context

The MAX6312UK29D3+ implements a dual-monitoring architecture: one internal factory-trimmed voltage divider sets the primary 2.9V VCC reset threshold, while a separate comparator monitors the RST IN pin against a precise 1.23V reference. Its active-high push/pull RESET output ensures immediate drive capability without external pull-ups, and the MR input supports debounced manual reset with glitch rejection of 0.1µs.

This device belongs to the MAX6305–MAX6313 family optimized for multivoltage system supervision. It guarantees operation across –40°C to +85°C, maintains reset assertion during VCC dips as low as 1.0V, and uses hysteresis (2.5mV on RST IN, ~2×VTH on VCC) to prevent chatter during threshold crossings - critical for stable microprocessor initialization in portable and industrial equipment.

Key Specifications

Pinout & Package

MAX6312UK29D3+ is housed in a lead-free 5-pin SOT23 package (package code U5+1, outline 21-0057), measuring 2.9mm × 1.6mm × 1.1mm, suitable for high-density PCB layouts in space-constrained portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6312UK29D3+, the MAX6312EUK29D3+ offers identical functionality with extended thermal qualification, while the TPS3808G33DBVR sacrifices dual-input flexibility and manual reset for TI ecosystem alignment and fixed-threshold simplicity - making MAX6312UK29D3+ optimal for cost-sensitive, dual-rail commercial designs needing full feature set.

Availability

MAX6312UK29D3+ is available at Aetrix Electronics and suitable for industrial PLCs, portable medical devices, smart energy meters, and automotive body control units requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.

Supply support for MAX6312UK29D3+ 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 product line was designed specifically for multivoltage microprocessor supervision in space-constrained, low-power systems - emphasizing precision threshold accuracy, transient immunity, and minimal external component count.

FAQ

What is the exact factory-set reset threshold voltage for MAX6312UK29D3+?

The MAX6312UK29D3+ has a factory-trimmed VCC reset threshold of 2.9V with a tolerance of ±2.5% over the full temperature range (–40°C to +85°C). This value is laser-trimmed during production and documented in the Electrical Characteristics table under "Reset Threshold (VTH)" for MAX6312/MAX6312E devices. The "29" in the part number explicitly denotes the 2.9V nominal threshold per Maxim's ordering convention.

Does MAX6312UK29D3+ support monitoring a second voltage rail besides VCC?

Yes, MAX6312UK29D3+ supports monitoring a second voltage rail via its RST IN pin, which compares an externally divided voltage against an internal 1.23V reference. This allows independent supervision of a 3.3V, 5V, or other rail using two resistors - a key differentiator from single-input reset supervisors. The device asserts RESET if either VCC falls below 2.9V or the RST IN voltage drops below 1.23V.

What is the function of the MR pin on MAX6312UK29D3+ and how should it be used?

The MR (Manual Reset) pin on MAX6312UK29D3+ is an active-low input that forces RESET assertion when pulled low. It features an internal 63.5kΩ pull-up resistor, so it may be left unconnected or tied to VCC for normal operation. To initiate manual reset, connect a normally open momentary switch between MR and GND. No external debounce components are required due to built-in 0.1µs glitch rejection.

Is MAX6312UK29D3+ compatible with 3.3V microcontrollers that require an active-high reset signal?

Yes, MAX6312UK29D3+ provides an active-high push/pull RESET output, making it directly compatible with 3.3V µPs requiring high-true reset assertion. Unlike open-drain reset ICs, it sources up to 150µA at VCC ≥ 1.8V and sinks up to 1.2mA - eliminating the need for an external pull-up resistor and ensuring robust drive strength across its operating voltage range.

What is the minimum VCC voltage at which MAX6312UK29D3+ guarantees valid RESET output operation?

MAX6312UK29D3+ guarantees valid RESET output logic levels down to VCC = 1.0V, as specified in the Electrical Characteristics table under "RESET Output Voltage (VOH/VOL)". Below this voltage, output drive capability degrades, but the device continues asserting RESET until VCC falls below the functional minimum of 2.97V (VTH + 2.5%). This ensures safe µP shutdown sequencing during deep brownout events.