Analog Devices Inc./Maxim Integrated MAX6309UK32D1+T

Overview

The MAX6309UK32D1+T from Maxim Integrated is a 5-pin SOT23 programmable supervisory IC that monitors VCC (factory-set at 3.2V ±2.5%), an adjustable undervoltage input (RST IN), and a manual-reset input (MR) to assert an active-low push/pull RESET output. It guarantees valid reset assertion down to VCC = 1V, features 8µA supply current, and provides a 1ms minimum reset timeout period. It is used in multivoltage embedded systems requiring reliable power-on and brownout reset control.

For engineers reviewing the MAX6309UK32D1+T datasheet, MAX6309UK32D1+T pinout, MAX6309UK32D1+T application, or MAX6309UK32D1+T equivalent, this page delivers verified technical context, factory-trimmed threshold accuracy, MR timing behavior, transient immunity specs, and real-world design implications for portable and industrial microprocessor supervision.

Technical Context

The MAX6309UK32D1+T implements a dual-monitoring architecture: its internal factory-trimmed voltage divider sets the primary VCC reset threshold at 3.2V, while a dedicated RST IN pin accepts externally scaled undervoltage signals referenced to a 1.23V internal comparator. The MR input includes a 63.5kΩ internal pull-up and guarantees reset assertion for ≥1.5µs MR low pulse width across temperature.

Its push/pull RESET output drives high/low with guaranteed VOH ≥0.8×VCC (at ISOURCE = 500µA, VCC > 2.5V) and VOL ≤0.3V (at ISINK = 1.2mA, VCC > 2.5V), enabling direct interface with CMOS/TTL logic without external pull-ups. Reset timeout is factory-programmed to D1 = 1ms (min), with propagation delay stable over –40°C to +85°C.

Key Specifications

Pinout & Package

MAX6309UK32D1+T is housed in a RoHS-compliant, lead-free 5-pin SOT23 package (outline U5+1, land pattern 90-0174), measuring 2.9mm × 1.6mm × 1.1mm, optimized for space-constrained PCB layouts in portable and embedded designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6309UK32D1+T, the MAX6309UK32D2+T extends reset duration for slower peripherals, while the TPS3808G33DBVR trades multi-input flexibility for lower quiescent current and simpler integration-neither offers pin-compatible replacement without layout or firmware changes.

Availability

MAX6309UK32D1+T is available at Aetrix Electronics and suitable for portable computers, industrial controllers, intelligent instruments, and multivoltage embedded systems requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

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 demanding industrial, automotive, and computing applications, with emphasis on reliability, low power, and integration.

The MAX6305–MAX6313 family was engineered specifically for multirail microprocessor supervision in space- and power-constrained systems, combining factory-trimmed accuracy, transient immunity, and flexible input configurations in a 5-pin SOT23 package.

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 full operating temperature range (–40°C to +85°C). This value is confirmed in Table 1 of the datasheet and corresponds to the "32" suffix in the part number. The MAX6309UK32D1+T uses an internal resistor divider to achieve this precision without external components.

Does MAX6309UK32D1+T support manual reset functionality, and how is it implemented?

Yes, MAX6309UK32D1+T includes a dedicated MR (manual-reset) input on pin 4. It features an internal 63.5kΩ pull-up resistor, so the pin can be left unconnected or tied to VCC if unused. Pulling MR low for ≥1.5µs asserts RESET and holds it active for the full 1ms timeout period after MR returns high. This enables hardware-level field reset without firmware involvement.

What is the guaranteed RESET output behavior of MAX6309UK32D1+T when VCC drops below 1.0V?

The MAX6309UK32D1+T guarantees valid RESET assertion down to VCC = 1.0V, meaning the output remains a defined logic low during brownout conditions until VCC falls below that level. Below 1.0V, push/pull drive capability degrades; however, for applications requiring validity to 0V, a 100kΩ pull-down resistor from RESET to GND maintains a solid low state, as documented in the Applications Information section.

Can MAX6309UK32D1+T monitor a second voltage rail besides VCC, and how is that configured?

Yes, MAX6309UK32D1+T monitors a second rail via the RST IN pin (pin 3), which compares an externally applied voltage against a precise 1.23V internal reference. To monitor, for example, a 5V rail at 4.5V threshold, use a resistor divider (R1 = 1.2MΩ, R2 = 180kΩ) to scale the rail down to 1.23V at RST IN. The MAX6309UK32D1+T datasheet provides the exact formula and noise-immunity guidance for this configuration.

What is the reset timeout period programmed into MAX6309UK32D1+T, and is it adjustable?

The MAX6309UK32D1+T is factory-programmed with a D1 reset timeout period of 1ms (minimum), as indicated by the "D1" in its part number. This timeout is fixed and non-adjustable-no external capacitor or resistor modifies it. The internal timer begins only after all monitored voltages (VCC and RST IN) exceed their respective thresholds and ensures the µP remains held in reset for at least 1ms before release.