Analog Devices Inc./Maxim Integrated MAX6426UK16+

Overview

MAX6426UK16+ 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 1.575 V (typical), with capacitor-adjustable reset timeout (275 µs to >5 ms), guaranteed operation down to VCC = 1 V, and quiescent current of 1.6 µA (typ). It serves as a system-level power-on reset controller in battery-powered embedded controllers.

For engineers reviewing the MAX6426UK16+ datasheet, MAX6426UK16+ pinout, MAX6426UK16+ application, or MAX6426UK16+ equivalent, key selection criteria include its 1.575 V reset threshold accuracy (±1.5% at +25°C), SOT23-5 open-drain output architecture, capacitor-programmable timeout, immunity to sub-50 µs VCC transients, and guaranteed reset validity at VCC ≥ 1 V.

Technical Context

The MAX6426UK16+ implements a precision voltage detector with laser-trimmed internal resistors setting the 1.575 V nominal reset threshold, combined with a 240 nA constant-current ramp source charging an external capacitor on the SRT pin to generate the reset timeout delay. Its open-drain RESET output requires an external pullup and supports logic-level interfacing across 0–5.5 V domains.

It operates over –40°C to +125°C, features hysteresis of 4 × VTH (≈6.3 mV), guarantees valid RESET assertion down to VCC = 1 V, and exhibits immunity to short negative-going VCC transients - e.g., ≤50 µs duration for 100 mV overdrive below VTH - ensuring robust brownout detection without false triggering.

Key Specifications

Pinout & Package

MAX6426UK16+ is housed in a 5-pin SOT23-5 package (package code U5+2), RoHS-compliant, with exposed pad not electrically connected. Pin 3 is NC (not internally connected) and may be tied to GND for mechanical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PST9216 and NCP302LSN16T1G, MAX6426UK16+ uniquely combines ultra-low ICC (1.6 µA), guaranteed reset validity down to VCC = 1 V, and fully capacitor-adjustable timeout - enabling optimized power efficiency, robust low-voltage operation, and precise timing alignment across diverse µP platforms.

Availability

MAX6426UK16+ is available at Aetrix Electronics and suitable for battery-powered controllers, automotive body electronics, and portable medical devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6426UK16+ 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 high-performance analog and mixed-signal semiconductor solutions for power, sensing, and interface applications.

The MAX6421–MAX6426 family delivers low-power, capacitor-programmable reset supervisors targeting space-constrained, battery-sensitive systems requiring precise voltage monitoring and flexible reset timing.

FAQ

What is the exact reset threshold voltage of MAX6426UK16+ and how accurate is it?

The MAX6426UK16+ has a nominal reset threshold of 1.575 V, 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 at wafer test and confirmed in the Electrical Characteristics table under VTH parameter. The suffix "16" in MAX6426UK16+ explicitly denotes this 1.575 V threshold per Table 1 of the datasheet.

Does MAX6426UK16+ support operation below 1.6 V supply, and what happens to RESET output at low VCC?

Yes, MAX6426UK16+ guarantees valid RESET assertion down to VCC = 1.0 V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. Below 1.0 V, RESET output current-sinking capability declines sharply. For applications requiring logic-valid RESET down to 0 V, a 100 kΩ pulldown resistor from RESET to GND is recommended - a design detail explicitly covered in the Applications Information section for MAX6426UK16+.

How is the reset timeout period set on MAX6426UK16+, and what capacitor value gives ~4.375 ms?

The reset timeout period on MAX6426UK16+ is set by connecting a capacitor (CSRT) between the SRT pin and GND. Using the formula tRP = 2.73 × 10⁶ × CSRT + 275 µs, a 1500 pF capacitor yields a typical timeout of 4.375 ms - matching the datasheet's tRP specification at that capacitance. Ceramic capacitors with leakage <10 nA are recommended, as stated in the Selecting a Reset Capacitor section.

Can MAX6426UK16+ be used in wired-OR reset configurations, and how is this implemented?

Yes, MAX6426UK16+ supports wired-OR reset via its open-drain RESET output. As shown in Figure 2 of the datasheet, an external open-drain logic signal (e.g., from another supervisor or watchdog) can be connected directly to the MAX6426UK16+ RESET pin. This allows auxiliary circuitry to hold the system in reset, though the external signal does not trigger the internal timeout - only the MAX6426UK16+'s own VCC monitoring initiates the full timeout sequence.

Is MAX6426UK16+ pin-compatible with other reset ICs, and which ones are documented alternatives?

Yes, the MAX6426UK16+ is documented as pin-compatible with PST92XX series devices (per Benefits and Features section). Specifically, PST9216 shares identical SOT23-5 pinout, 1.575 V threshold, and open-drain output. However, MAX6426UK16+ offers lower quiescent current (1.6 µA vs. 3.5 µA) and guaranteed operation down to VCC = 1 V - distinctions confirmed in the Electrical Characteristics and Applications Information sections of the MAX6426UK16+ datasheet.