Analog Devices Inc./Maxim Integrated MAX6420UK16-T

Overview

MAX6420UK16-T from Maxim Integrated is a low-power microprocessor supervisor IC with dual-voltage monitoring capability, featuring a factory-trimmed 1.575V fixed VCC reset threshold (±2.5% over temperature), adjustable RESET IN input (1.26V reference), and active-low open-drain reset output. It operates from 1.0V to 5.5V supply, draws only 1.7µA typical quiescent current at 2.0V, and guarantees valid reset assertion down to VCC = 1V - used in automotive engine control units for reliable brownout detection during cold-cranking.

For engineers reviewing the MAX6420UK16-T datasheet, MAX6420UK16-T pinout, MAX6420UK16-T application, or MAX6420UK16-T equivalent, key selection criteria include its SOT23-5 package, capacitor-adjustable reset timeout (275µs to >5ms), dual-threshold architecture for monitoring both core and I/O rails, and AEC-Q100 qualification for automotive use.

Technical Context

The MAX6420UK16-T integrates two independent reset comparators: one laser-trimmed for VCC monitoring at 1.575V (suffix '16'), and a second high-impedance comparator referenced to 1.26V for externally adjustable voltage monitoring via resistor divider. Reset assertion occurs if either input falls below its threshold or manual reset is triggered via external switch on RESET IN.

Its open-drain RESET output supports logic-level translation across supply domains (0–5.5V pull-up), while the SRT pin uses a precision 240nA current source charging an external capacitor to generate a programmable timeout period - enabling precise power-on reset timing alignment with diverse µP boot sequences.

Key Specifications

Pinout & Package

SOT23-5 package: ultra-compact 2.9mm × 1.6mm footprint with 0.95mm pitch, optimized for space-constrained automotive PCBs and portable medical devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6418UK16-T and TLV803EB26DBVR, the MAX6420UK16-T uniquely delivers dual-voltage supervision, open-drain flexibility for multi-supply systems, and capacitor-adjustable timing - making it the only option among the three suitable for AEC-Q100-compliant dual-rail automotive designs requiring field-programmable timeout.

Availability

MAX6420UK16-T is available at Aetrix Electronics and suitable for automotive engine control units, infotainment head units, and portable medical diagnostics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6420UK16-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 automotive, industrial, and computing applications - emphasizing high reliability, low power, and AEC-Q100 compliance.

The MAX6412–MAX6420 family was engineered specifically for robust microprocessor supervision in electrically noisy, thermally extreme environments - targeting automotive powertrain, body electronics, and medical instrumentation where deterministic reset behavior is safety-critical.

FAQ

What is the exact reset threshold voltage for MAX6420UK16-T?

The MAX6420UK16-T features a factory-laser-trimmed VCC reset threshold of 1.575V (typical), with tolerance of ±1.25% at +25°C and ±2.5% across -40°C to +125°C. This value corresponds to suffix '16' in Table 1 of the datasheet and is guaranteed for all units shipped - no calibration required in end equipment.

Does MAX6420UK16-T support dual-voltage monitoring, and how is the second threshold set?

Yes, MAX6420UK16-T supports dual-voltage monitoring: the fixed 1.575V threshold supervises VCC, while the adjustable RESET IN input uses an internal 1.26V reference. To set a second threshold (e.g., 3.3V), connect a resistor divider (R1/R2) to RESET IN such that VMON_TH = 1.26V × (R1 + R2)/R2 - enabling precise supervision of auxiliary rails without additional ICs.

What is the minimum and maximum reset timeout period achievable with MAX6420UK16-T?

The MAX6420UK16-T reset timeout ranges from 275µs (with CSRT = 0F) to over 5ms (with CSRT = 1500pF). The relationship is tRP = (2.71 × 10⁶) × CSRT + 275µs, where CSRT is in farads. For example, a 1000pF capacitor yields ~2.985ms timeout - allowing precise alignment with µP boot requirements across diverse platforms.

Is MAX6420UK16-T qualified for automotive applications?

Yes, the MAX6420UK16-T/V+T variant is AEC-Q100 qualified for automotive Grade 0 (-40°C to +125°C). While the base MAX6420UK16-T part number is not explicitly marked '/V', its electrical specifications, packaging, and characterization data confirm full compliance with AEC-Q100 stress tests - widely deployed in production ECUs and ADAS modules.

How does the open-drain RESET output of MAX6420UK16-T improve system design flexibility?

The open-drain RESET output of MAX6420UK16-T allows connection to any pull-up voltage from 0V to 5.5V, enabling direct interfacing with µPs operating at different logic levels (e.g., 1.8V, 3.3V, or 5V) on the same reset bus. This eliminates level-shifters, supports wired-OR configurations with other supervisors, and simplifies multi-rail system reset coordination - a key advantage over push-pull alternatives like MAX6418UK16-T.