Analog Devices Inc./Maxim Integrated MAX6421XS23-T

Overview

MAX6421XS23-T from Maxim Integrated is a low-power, active-low push-pull microprocessor reset supervisor IC designed for precise VCC monitoring and capacitor-adjustable reset timeout in space-constrained systems. It monitors supply voltages from 1.6V to 5V, features ±1.5% reset threshold accuracy at +25°C, guarantees valid reset operation down to VCC = 1V, and draws only 1.6µA typical quiescent current-enabling reliable brownout protection in battery-powered medical instruments and portable controllers.

For engineers reviewing the MAX6421XS23-T datasheet, MAX6421XS23-T pinout, MAX6421XS23-T application, or MAX6421XS23-T equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative options for voltage-monitoring reset circuits requiring SC70-4 packaging and factory-trimmed 2.3V reset thresholds.

Technical Context

The MAX6421XS23-T implements a precision bandgap-based voltage detector with laser-trimmed internal resistors to set its nominal 2.3V reset threshold (suffix "23" per Table 1), achieving ±1.5% accuracy at +25°C and ±2.5% over –40°C to +125°C. Its reset assertion is triggered by VCC falling below VTH, and deassertion is delayed by an externally adjustable timeout determined by a ramp current (240nA) charging CSRT to a 0.65V internal reference.

This device uses a dedicated SRT pin to control timeout via external capacitor (tRP = 2.73×10⁶ × CSRT + 275µs), supports push-pull active-low RESET output capable of sinking 3.2mA at VCC ≥ 4.5V (VOL = 0.4V), and maintains guaranteed logic validity for VCC ≥ 1.0V-making it suitable for low-voltage embedded systems where deterministic power-up sequencing and glitch immunity are critical.

Key Specifications

Pinout & Package

MAX6421XS23-T is housed in a 4-pin SC70-4 package (outline 21-0098), with 0.65mm pitch, 1.25mm × 0.85mm body size, and thermal pad omitted. Pin 1 is marked with a dot; pin numbering follows standard SC70 top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6421XS23-T, MAX6421US23-T offers identical functionality in a larger but thermally robust SOT143 package, while TLV803EB23DBZR trades adjustability and ultra-low current for simplicity and lower cost-neither is pin-compatible, and both require PCB redesign.

Availability

MAX6421XS23-T is available at Aetrix Electronics and suitable for battery-powered medical monitors, industrial embedded controllers, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for MAX6421XS23-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, automotive, and medical markets.

The MAX6421–MAX6426 family delivers ultra-low-power, capacitor-programmable reset supervisors targeting portable and energy-sensitive systems where accurate voltage monitoring and flexible reset timing are essential.

FAQ

What is the exact reset threshold voltage of MAX6421XS23-T?

The MAX6421XS23-T has a factory-laser-trimmed nominal reset threshold of 2.3V, with ±1.5% accuracy at +25°C and ±2.5% over the full –40°C to +125°C operating range. This value is confirmed by suffix "23" in the part number and Table 1 of the datasheet, and applies specifically to the MAX6421XS23-T-not the broader MAX6421 family.

How do I calculate the reset timeout period for MAX6421XS23-T?

For MAX6421XS23-T, the reset timeout period tRP (in seconds) is calculated as tRP = (2.73 × 10⁶) × CSRT + 275µs, where CSRT is the capacitor value in farads connected between SRT and GND. For example, a 1500pF capacitor yields tRP ≈ 4.375ms. This formula is device-specific and validated in the Electrical Characteristics table.

Does MAX6421XS23-T support operation below 1.6V supply?

Yes-MAX6421XS23-T is fully specified down to VCC = 1.0V, with guaranteed reset assertion and deassertion functionality. Its supply voltage range is 1.0V to 5.5V, and reset output remains valid (VOL ≤ 0.4V, VOH ≥ 0.8×VCC) for VCC ≥ 1.0V, enabling use in deep-brownout scenarios where other supervisors fail.

What package type does MAX6421XS23-T use, and is it lead-free?

MAX6421XS23-T uses the 4-pin SC70-4 package (outline 21-0098), measuring 1.25mm × 0.85mm with 0.65mm pitch. It is available in lead-free format; the "-T" suffix denotes lead-free packaging per Maxim's ordering conventions, and RoHS compliance is confirmed in the Package Information section.

Can MAX6421XS23-T replace MAX6421XS22-T in an existing design?

MAX6421XS23-T can replace MAX6421XS22-T only if the system requires a 2.3V reset threshold instead of 2.2V. Both share identical SC70-4 packaging, pinout, and electrical behavior except for threshold voltage-so no PCB changes are needed, but the reset trip point shifts by 100mV, which must be verified against system rail tolerances.