Analog Devices Inc./Maxim Integrated MAX6309UK29D3

Overview

MAX6309UK29D3 from Maxim Integrated is a push/pull active-low reset IC with factory-programmed 2.93V V_CC reset threshold and 140ms minimum reset timeout period. It monitors V_CC via internal trimmed divider, includes manual reset (MR) input and adjustable undervoltage reset input (RST IN), and guarantees valid RESET output down to V_CC = 1V. Designed for multivoltage systems like 3V/5V embedded controllers.

For engineers reviewing the MAX6309UK29D3 datasheet, MAX6309UK29D3 pinout, MAX6309UK29D3 application, or MAX6309UK29D3 equivalent, key selection criteria include its 2.93V ±1.5% threshold accuracy, 8µA supply current, immunity to fast V_CC transients, guaranteed operation over 0°C to +70°C, and SOT23-5 package compatibility with space-constrained portable designs.

Technical Context

The MAX6309UK29D3 uses an internal factory-trimmed resistor divider to set its nominal 2.93V reset threshold on V_CC, with ±1.5% room-temperature tolerance and 40ppm/°C tempco. Its reset generator asserts active-low RESET for ≥140ms after all monitored supplies exceed their thresholds.

It features a dedicated MR input with 63.5kΩ internal pull-up, supports TTL/CMOS logic drive, and includes an adjustable RST IN comparator referenced to 1.23V - enabling external monitoring of secondary supplies. The device ignores short-duration negative-going V_CC transients per its transient immunity curves.

Key Specifications

Pinout & Package

SOT23-5 package: compact 2.9mm × 1.6mm surface-mount footprint with gull-wing leads, optimized for high-density PCB layouts in portable equipment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6310UK29D3 and TPS3808G33DBVR, the MAX6309UK29D3 uniquely balances precise 2.93V threshold accuracy, integrated manual reset, adjustable secondary-supply monitoring, and industry-standard SOT23-5 footprint - making it optimal for cost-sensitive, multivoltage embedded systems requiring robust brownout immunity.

Availability

MAX6309UK29D3 is available at Aetrix Electronics and suitable for industrial PLC modules, medical patient monitors, automotive infotainment head units, and smart energy meters requiring stable component supply with guaranteed long-term sourcing.

Supply support for MAX6309UK29D3 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 space-constrained, battery-sensitive applications - delivering precision reset thresholds, low quiescent current, and transient immunity in minimal SOT23-5 packaging.

FAQ

What is the exact factory-programmed reset threshold voltage for MAX6309UK29D3?

The MAX6309UK29D3 has a factory-programmed nominal V_CC reset threshold of 2.93V, with a tolerance of ±1.5% at +25°C and a temperature coefficient of 40ppm/°C. This value is confirmed in Table 1 of the datasheet and corresponds to the "UK29" suffix. The actual threshold ranges from 2.886V (min) to 3.000V (max) across the 0°C to +70°C operating range.

Does MAX6309UK29D3 support manual reset functionality, and how is it implemented?

Yes, the MAX6309UK29D3 includes a dedicated manual reset (MR) input on Pin 4. It is active-low, features an internal 63.5kΩ pull-up resistor, and asserts RESET for the full 140ms timeout period after MR returns high. The MR pin accepts TTL/CMOS logic levels and can be driven by a momentary switch to GND - no external components or debounce circuitry are required for standard use cases.

What is the minimum V_CC voltage at which MAX6309UK29D3 guarantees valid RESET output assertion?

The MAX6309UK29D3 guarantees valid active-low RESET output down to V_CC = 1V, as specified in the Electrical Characteristics table. Below this voltage, the push/pull output's sinking capability degrades significantly. For applications requiring reset assertion down to 0V, a 100kΩ pull-down resistor between RESET and GND is recommended - a design detail explicitly documented for the MAX6309UK29D3 in the Applications Information section.

How does MAX6309UK29D3 handle fast transients on the V_CC supply line?

The MAX6309UK29D3 is specifically designed to ignore fast V_CC transients, with immunity characterized in the "Maximum Transient Duration vs. V_CC Reset Threshold Overdrive" graph. For example, a 100mV negative-going glitch below the 2.93V threshold can be up to ~10µs wide without triggering reset. This behavior stems from internal filtering and comparator hysteresis (2×V_TH), and is a core feature validated across the entire MAX6305–MAX6313 family including the MAX6309UK29D3.

What package type and footprint does MAX6309UK29D3 use, and are there lead-free options?

The MAX6309UK29D3 is supplied in a 5-pin SOT23-5 package (2.9mm × 1.6mm), with gull-wing leads compatible with standard reflow soldering processes. Lead-free versions are available: replace the "-T" suffix with "+T" in the order code (e.g., MAX6309UK29D3+T). Both leaded and lead-free variants share identical electrical specifications and thermal performance per the Absolute Maximum Ratings table.