Analog Devices Inc./Maxim Integrated MAX6309UK32D1-T

Overview

MAX6309UK32D1-T from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC (factory-set to 3.2V ±2.5%), an adjustable undervoltage input (RST IN), and a manual reset (MR) input, asserting an active-low push/pull RESET output for microprocessor system initialization in multivoltage embedded systems. It guarantees valid reset down to VCC = 1V, consumes only 8µA supply current, and features 1ms minimum reset timeout.

For engineers reviewing the MAX6309UK32D1-T datasheet, MAX6309UK32D1-T pinout, MAX6309UK32D1-T application, or MAX6309UK32D1-T equivalent, key selection criteria include factory-trimmed 3.2V VCC threshold accuracy, MR input compatibility with TTL/CMOS logic, immunity to sub-1µs VCC transients, and guaranteed reset assertion across -0°C to +70°C ambient.

Technical Context

The MAX6309UK32D1-T implements a precision bandgap reference (1.23V ±0.03V) to compare VCC against its factory-trimmed 3.2V threshold via internal resistor divider, while RST IN operates independently with identical 1.23V comparator reference. Its push/pull RESET output sources ≥800µA at VCC > 4.25V and sinks ≥3.2mA - enabling direct interface with µP reset pins without external pull-up.

Reset assertion occurs when VCC falls below 3.2V × (1 − 2.5%) = 3.12V (min) or RST IN drops below 1.20V (min), with hysteresis of 2.5mV on RST IN and 2×VTH (≈6.4V) on VCC. The internal timer initiates only after all monitored inputs exceed thresholds, enforcing strict 1ms (min) delay before deassertion.

Key Specifications

Pinout & Package

MAX6309UK32D1-T is housed in a 5-pin SOT23 package (outline U5+1, land pattern 90-0174), measuring 2.9mm × 1.6mm × 1.1mm with gull-wing leads. Pin 1 is marked by a dot; device orientation follows JEDEC MO-178.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6312UK32D1-T, MAX6309UK32D1-T omits overvoltage monitoring to reduce pin count and cost; versus TPS3808G33DBVR, it trades lower quiescent current for greater configurability via MR and RST IN - making it optimal for field-serviceable or multirail designs.

Availability

MAX6309UK32D1-T is available at Aetrix Electronics and suitable for portable computers, intelligent instruments, and embedded control systems requiring stable component supply across commercial temperature range.

Supply support for MAX6309UK32D1-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, sensing, and interface applications in industrial, computing, and communications markets.

The MAX6305–MAX6313 family delivers programmable supervisory functions for multivoltage microprocessor systems, emphasizing factory-trimmed accuracy, transient immunity, and minimal external component count.

FAQ

What is the exact factory-programmed VCC reset threshold for MAX6309UK32D1-T?

The MAX6309UK32D1-T has a factory-trimmed VCC reset threshold of 3.2V, specified with ±2.5% tolerance over the −0°C to +70°C operating temperature range. This value corresponds to entry "32" in Table 1 of the datasheet, where nominal thresholds are defined in 100mV increments from 2.5V to 5.0V. The actual measured threshold at +25°C falls within 3.12V to 3.28V.

Does MAX6309UK32D1-T support manual reset functionality, and what are the input voltage requirements?

Yes, MAX6309UK32D1-T includes a dedicated MR pin with internal 63.5kΩ pull-up. It accepts TTL-level low signals (≤0.8V) and CMOS-level high signals (≥0.7×VCC), enabling direct connection to 3.3V or 5V logic. A minimum 1.5µs pulse width is required at temperature extremes, and the pin tolerates noise via optional 0.1µF capacitor to ground - no external debounce circuitry is needed.

What is the guaranteed minimum reset timeout period for MAX6309UK32D1-T, and how is it programmed?

The MAX6309UK32D1-T guarantees a minimum reset timeout of 1ms, corresponding to the "D1" suffix in its part number. This timeout is factory-programmed and non-adjustable; other options include D2 (20ms), D3 (140ms), and D4 (1120ms). The internal timer starts only after all monitored voltages (VCC and RST IN) exceed their respective thresholds, ensuring deterministic release timing.

Can MAX6309UK32D1-T monitor voltages other than VCC, and how is that implemented?

Yes, MAX6309UK32D1-T monitors a second voltage via its RST IN pin, which compares an external voltage against a precise 1.23V internal reference. Users implement this by connecting a resistor divider from the target voltage rail to RST IN and GND, calculating R1/R2 to trigger reset when the rail falls below the desired threshold. Input leakage is limited to ±25nA, allowing megohm-scale resistors without significant error.

What package type and RoHS status does MAX6309UK32D1-T use?

MAX6309UK32D1-T is supplied in a lead-free 5-pin SOT23 package (package code U5+1), compliant with RoHS Directive 2011/65/EU. The "-T" suffix denotes tape-and-reel packaging; leaded versions use "-T" without "+" prefix. Footprint dimensions follow JEDEC MO-178 standard, with 0.95mm pin pitch and 1.1mm maximum height.