Analog Devices Inc./Maxim Integrated MAX6423US29+T

Overview

MAX6423US29+T from Analog Devices is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.925V nominal reset threshold (±2.5% over temperature), capacitor-adjustable reset timeout (3.0–5.75ms at CSRT = 1500pF), 1.6µA typical supply current, and guaranteed operation down to VCC = 1V. It monitors system supply voltage in portable and battery-powered embedded controllers.

For engineers reviewing the MAX6423US29+T datasheet, MAX6423US29+T pinout, MAX6423US29+T application, or MAX6423US29+T equivalent, key selection criteria include its SOT143-4 package, open-drain RESET compatibility with multiple logic supplies, immunity to short VCC transients, and factory-laser-trimmed reset threshold accuracy.

Technical Context

This device implements a precision voltage-detection circuit with a laser-trimmed internal reference and a 240nA SRT ramp current source that charges an external capacitor to set the reset timeout period. The reset assertion is triggered when VCC falls below the 2.925V threshold, with hysteresis of 4 × VTH (≈11.7mV).

The open-drain RESET output requires an external pullup resistor (10kΩ–100kΩ) and supports logic-level interfacing up to 5.5V. It remains valid for VCC ≥ 1V, and its leakage current is specified at 1.0µA when deasserted.

Key Specifications

Pinout & Package

MAX6423US29+T is housed in a 4-pin SOT143-4 package (outline 21-0052, land pattern 90-0183), with 0.65mm pitch and lead-free (+) finish. Pin 1 is marked by a dot or beveled edge.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with NCP302LSN29T1G and TLV809EC29DBZR, MAX6423US29+T uniquely delivers capacitor-adjustable reset timing in a 4-pin SOT143 package with open-drain output - enabling design reuse across multiple µP families and supply configurations without layout changes.

Availability

MAX6423US29+T is available at Aetrix Electronics and suitable for battery-powered medical sensors, automotive body control modules, and industrial IoT edge nodes requiring stable component supply with long-term lifecycle support.

Supply support for MAX6423US29+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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

MAX6423US29+T belongs to the MAX6340/MAX6421–MAX6426 family of low-power microprocessor supervisors designed specifically for reliable power-monitoring in space- and energy-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6423US29+T and how does it vary with temperature?

The MAX6423US29+T has a nominal reset threshold of 2.925V, with ±1.5% accuracy at +25°C and ±2.5% over the full -40°C to +125°C operating range. This is confirmed by Table 1 in the datasheet, where suffix "29" corresponds to 2.852V (min), 2.925V (typ), and 2.998V (max). The normalized threshold vs. temperature curve (toc08) shows drift within ±0.5% across temperature.

Can MAX6423US29+T be used with a 1.8V microcontroller reset input?

Yes, MAX6423US29+T is fully compatible with 1.8V µP reset inputs. Its open-drain RESET output can be pulled up to 1.8V using a 10kΩ–100kΩ resistor. When asserted, RESET sinks ≥500µA at VCC ≥ 1.8V with VOL ≤ 0.3V, ensuring solid logic-low recognition. The device itself operates down to VCC = 1.0V, maintaining reset validity during brownout.

What capacitor value is required to achieve a 4.375ms reset timeout with MAX6423US29+T?

To achieve a 4.375ms reset timeout, MAX6423US29+T requires a 1500pF capacitor between SRT and GND. This is explicitly stated in the Electrical Characteristics table under "Reset Timeout Period" (tRP) with condition CSRT = 1500pF. The formula tRP = 2.73 × 10⁶ × CSRT + 275µs confirms this: (2.73e6 × 1500e−12) + 275e−6 = 4.375ms.

Is MAX6423US29+T pin-compatible with any other supervisor ICs?

MAX6423US29+T uses the 4-pin SOT143 package and is pin-compatible with other members of the MAX6421–MAX6423 series in the same package (e.g., MAX6421US29+T, MAX6422US29+T), differing only in RESET output polarity and drive type. It is not pin-compatible with 5-pin SOT23 variants like MAX6425UK29+T due to different pin count and assignment.

Does MAX6423US29+T meet automotive qualification standards?

MAX6423US29+T itself is not AEC-Q100 qualified per the datasheet, which specifies AEC-Q100 qualification only for the MAX6340UK31/V+T variant. However, it shares the same BiCMOS process and operates across -40°C to +125°C, making it suitable for non-safety-critical automotive subsystems where full qualification is not mandated.