Analog Devices Inc./Maxim Integrated MAX6426UK22

Overview

MAX6426UK22 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 2.188V (typical), with capacitor-adjustable reset timeout, guaranteed operation down to VCC = 1V, and 1.6µA typical quiescent current - used in battery-powered controllers and automotive ECUs for reliable power-on reset sequencing.

For engineers reviewing the MAX6426UK22 datasheet, MAX6426UK22 pinout, MAX6426UK22 application, or MAX6426UK22 equivalent, key selection criteria include its 2.188V reset threshold accuracy (±2.5% over temperature), SOT23-5 open-drain output compatibility with mixed-voltage µP interfaces, capacitor-set timeout (275µs to >5ms), and AEC-Q100-compliant variants for automotive use.

Technical Context

The MAX6426UK22 implements a precision voltage detector with laser-trimmed internal reference and hysteresis (4×VTH), comparing VCC against a factory-set 2.188V threshold. Its reset assertion logic is triggered by VCC falling below VTH and held active for a user-defined timeout period determined by external capacitor CSRT charging via a 240nA ramp current source to a 0.65V internal reference.

As an open-drain supervisor, MAX6426UK22 requires an external pullup resistor (10kΩ–100kΩ) to any supply up to 5.5V, enabling wired-OR reset capability and logic-level translation across heterogeneous voltage domains - critical for systems integrating multiple µPs or FPGAs with differing I/O thresholds.

Key Specifications

Pinout & Package

MAX6426UK22 is housed in a 5-pin SOT23-5 package (package code U5+2), RoHS-compliant, with 0.95mm pitch and 2.9mm × 1.6mm footprint - compatible with standard high-volume SMT assembly processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PST9222 and NCP302LSN22T1G, MAX6426UK22 uniquely combines automotive-grade temperature performance, capacitor-adjustable timeout, and sub-2µA quiescent current - making it the sole option for AEC-Q100-compliant, battery-sensitive, and timing-flexible embedded systems.

Availability

MAX6426UK22 is available at Aetrix Electronics and suitable for automotive engine control units, portable medical monitors, industrial PLC modules, and set-top box power management requiring stable component supply, long-lifecycle support, and AEC-Q100-aligned sourcing.

Supply support for MAX6426UK22 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 - emphasizing reliability, low power, and high integration.

The MAX6426UK22 belongs to the MAX6340/MAX6421–MAX6426 family of capacitor-programmable µP supervisors, engineered specifically for robust reset generation in battery-constrained and thermally harsh environments.

FAQ

What is the exact reset threshold voltage of MAX6426UK22?

The MAX6426UK22 has a factory-trimmed nominal reset threshold of 2.188V, with ±1.5% accuracy at +25°C and ±2.5% over the full -40°C to +125°C operating range. This value is laser-trimmed and specified in Table 1 of the datasheet under suffix "22", ensuring predictable brownout detection without external calibration.

Does MAX6426UK22 support capacitor-adjustable reset timeout, and how is it calculated?

Yes, MAX6426UK22 supports capacitor-adjustable reset timeout via the SRT pin. The timeout period tRP (in seconds) is calculated as tRP = 2.73 × 10⁶ × CSRT + 275µs, where CSRT is the external capacitor in farads. For example, a 1500pF capacitor yields a typical tRP of 4.375ms - enabling precise alignment with µP reset timing requirements.

What package type and pin configuration does MAX6426UK22 use?

MAX6426UK22 uses a 5-pin SOT23-5 package (outline 21-0057) with pin 1 = GND, pin 2 = VCC, pin 3 = SRT, pin 4 = N.C., and pin 5 = RESET. The N.C. pin is unconnected internally and may be left floating or grounded; the open-drain RESET output requires an external pullup resistor for proper logic-level definition.

Is MAX6426UK22 qualified for automotive applications?

While MAX6426UK22 itself is not explicitly AEC-Q100 qualified in its base ordering part number, the MAX6340UK22/V+T variant (same threshold and package) is AEC-Q100 qualified. MAX6426UK22 shares identical electrical specs, temperature range (-40°C to +125°C), and construction - making it suitable for automotive designs where full qualification documentation is managed at the system level.

How does the open-drain RESET output of MAX6426UK22 interface with different logic supplies?

The open-drain RESET output of MAX6426UK22 can be pulled up to any voltage from 0V to 5.5V, enabling direct interface with 1.8V, 3.3V, or 5V µP reset inputs without level shifters. A 10kΩ–100kΩ pullup resistor ensures sufficient drive strength while minimizing current draw - supporting mixed-voltage system architectures and wired-OR reset busing.