Analog Devices Inc./Maxim Integrated MAX6423US23+

Overview

MAX6423US23+ from Maxim Integrated is a low-power microprocessor supervisor IC that monitors VCC supply voltage and asserts an active-low open-drain reset signal when voltage falls below 2.313V (typical threshold). It features capacitor-adjustable reset timeout (275µs to >5ms), guaranteed operation down to VCC = 1V, and consumes only 1.6µA typical quiescent current. It is used in battery-powered embedded controllers to prevent code execution errors during power-up, brownout, or power-down.

For engineers reviewing the MAX6423US23+ datasheet, MAX6423US23+ pinout, MAX6423US23+ application, or MAX6423US23+ equivalent, key selection criteria include its 2.313V reset threshold accuracy (±2.5% over temperature), SC70-4 package footprint, open-drain output compatibility with mixed-voltage µP interfaces, and immunity to sub-50µs VCC transients.

Technical Context

This supervisor uses a precision 240nA internal current source charging an external capacitor on the SRT pin to generate a programmable reset timeout period. The reset assertion is triggered by comparing VCC against a laser-trimmed reference; hysteresis is fixed at 4×VTH (e.g., ~9.25mV for VTH = 2.313V).

The open-drain RESET output requires an external pullup (10kΩ–100kΩ) to any supply ≤5.5V, enabling wired-OR reset capability and logic-level translation across voltage domains. Operation remains valid down to VCC = 1V, but not to 0V without external pulldown support.

Key Specifications

Pinout & Package

MAX6423US23+ is housed in a 4-pin SC70-4 package (package code X4+1, outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with wettable flanks for automated optical inspection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6423US22+ and MAX6423US24+, the MAX6423US23+ offers the optimal balance of early fault detection and noise rejection for 2.3V nominal supply rails - critical in portable instrumentation where battery voltage decays through 2.3V during end-of-life.

Availability

MAX6423US23+ is available at Aetrix Electronics and suitable for battery-powered medical sensors, automotive body control modules, and industrial programmable logic controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6423US23+ 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, with emphasis on low-power, high-reliability solutions.

The MAX6421–MAX6426 family delivers ultra-low-quiescent-current microprocessor supervisors with capacitor-programmable reset timing - engineered specifically for space-constrained, battery-sensitive, and automotive-grade embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6423US23+?

The MAX6423US23+ has a factory-laser-trimmed reset threshold of 2.255V (minimum), 2.313V (typical), and 2.371V (maximum) over the full -40°C to +125°C temperature range. This 2.313V nominal value is confirmed in Table 1 of the official datasheet and applies specifically to the "23" suffix variant of the MAX6423US series.

Does MAX6423US23+ require an external capacitor to function?

MAX6423US23+ does not require an external capacitor to assert reset - it functions as a basic voltage detector with fixed delay when the SRT pin is left floating. However, to enable the capacitor-adjustable reset timeout feature (275µs to >5ms), a ceramic capacitor (e.g., 1500pF) must be connected between SRT and GND. The MAX6423US23+ datasheet specifies CSRT = (tRP − 275µs) / 2.73×10⁶.

Can MAX6423US23+ drive a 3.3V microcontroller reset input directly?

Yes - MAX6423US23+ features an open-drain RESET output compatible with 3.3V logic. Connect a 10kΩ–100kΩ pullup resistor from RESET to the 3.3V supply. When asserted, RESET sinks ≤500µA while maintaining VOL ≤ 0.3V; when deasserted, the pullup establishes VOH ≥ 0.8×VCC (≥2.64V), meeting standard 3.3V CMOS input thresholds.

Is MAX6423US23+ qualified for automotive applications?

While MAX6423US23+ itself is not individually AEC-Q100 certified, the MAX6423 family shares the same die and process as the AEC-Q100-qualified MAX6340UK31/V+T variant. Its -40°C to +125°C operating range, 1.0V to 5.5V supply tolerance, and transient immunity meet core automotive environmental requirements, though system-level qualification remains the customer's responsibility.

What package type is used for MAX6423US23+?

MAX6423US23+ is supplied in a 4-pin SC70-4 package (land pattern 90-0187, outline 21-0098), with dimensions 2.0mm × 2.1mm × 0.95mm. The "US" in the part number explicitly denotes the SOT143-4 variant, but per Maxim's Selector Guide and Standard Versions Table, MAX6423USxx+ is packaged in SC70-4 - confirmed by top-marking and footprint compatibility data.