Analog Devices Inc./Maxim Integrated MAX6837VXSD0+

Overview

MAX6837VXSD0+ from Maxim Integrated is an ultra-low-voltage microprocessor supervisory circuit with open-drain active-low reset output, 1.575V factory-set reset threshold, and 1.5ms reset timeout period. It monitors +1.2V to +1.8V supplies in portable and battery-powered systems, asserting reset during brownout or power-down events while consuming only 7.5µA typical supply current.

For engineers reviewing the MAX6837VXSD0+ datasheet, MAX6837VXSD0+ pinout, MAX6837VXSD0+ application, or MAX6837VXSD0+ equivalent, key selection criteria include its SC70-4 package, debounced manual reset input (MR), ±2.5% threshold accuracy over temperature, and compatibility with bidirectional µP reset pins via open-drain configuration.

Technical Context

The MAX6837VXSD0+ implements a precision voltage comparator with hysteresis (0.75% of VTH) and a fixed 1.5ms timeout timer triggered by VCC falling below 1.575V or MR assertion. Its internal 20kΩ MR pullup enables direct switch interfacing without external components.

This device belongs to the MAX6832–MAX6840 family of SC70-packaged supervisors optimized for low-power, space-constrained applications. It uses BiCMOS process technology (681 transistors) and guarantees valid reset operation down to VCC = 0.55V with open-drain output sinking capability.

Key Specifications

Pinout & Package

MAX6837VXSD0+ is housed in a 4-pin SC70 package (2.0mm × 2.1mm, 0.65mm pitch) with exposed pad for thermal performance. Pin 1 = GND, Pin 2 = RESET (open-drain), Pin 3 = MR (debounced manual reset), Pin 4 = VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar µP supervisory applications.

Compared with MAX6837VXSD0+, MAX6835VXSD0+ simplifies BOM by eliminating the pullup resistor but sacrifices level-shifting flexibility, while MAX6381XR29D3+ trades manual reset for extended timeout-making MAX6837VXSD0+ optimal for compact, field-serviceable embedded devices.

Availability

MAX6837VXSD0+ is available at Aetrix Electronics and suitable for wearable health monitors, industrial sensor nodes, and portable medical diagnostics requiring stable component supply across long production lifecycles.

Supply support for MAX6837VXSD0+ 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 management, sensing, and connectivity in demanding environments.

The MAX6832–MAX6840 product line delivers ultra-low-voltage supervisory circuits targeting portable, battery-powered, and space-constrained embedded systems requiring high accuracy and minimal quiescent current.

FAQ

What is the exact reset threshold voltage of the MAX6837VXSD0+ and how stable is it over temperature?

The MAX6837VXSD0+ has a factory-set reset threshold of 1.575V with ±2.5% accuracy over the full operating temperature range of -40°C to +85°C. This specification is guaranteed by design and verified across temperature extremes-not just at +25°C-ensuring reliable brownout detection in automotive and industrial environments where ambient temperature fluctuates significantly. The MAX6837VXSD0+ maintains this stability using precision bandgap references and matched transistor ratios in its BiCMOS process.

Does the MAX6837VXSD0+ require an external pullup resistor on the RESET pin, and what value is recommended?

Yes, the MAX6837VXSD0+ requires an external pullup resistor on its open-drain RESET pin because it cannot drive high actively. A 10kΩ to 100kΩ resistor pulled to the target logic rail (e.g., 3.3V or 5V) is recommended. Lower values ensure faster rise time for high-speed µPs; higher values minimize current draw in battery-critical applications. The MAX6837VXSD0+ can sink up to 200µA at VCC ≥ 1.5V, so the chosen resistor must keep VOL ≤ 0.2V under worst-case sink conditions.

Can the MAX6837VXSD0+ be used to monitor a supply voltage other than VCC, such as a separate I/O rail?

No-the MAX6837VXSD0+ monitors only the VCC pin voltage; it does not support external threshold adjustment like the MAX6838/MAX6839/MAX6840 series. For monitoring non-VCC rails (e.g., 3.3V I/O while VCC is 1.6V), use the MAX6838VXSD0+ with RESET-IN pin and external resistor divider. The MAX6837VXSD0+ is strictly a VCC-supply supervisor with fixed 1.575V threshold, making it unsuitable for adjustable or multi-rail monitoring applications.

How does the debounced manual reset (MR) input on the MAX6837VXSD0+ work, and what is its minimum pulse width requirement?

The MAX6837VXSD0+ integrates hardware debounce on its MR input, rejecting glitches shorter than 100ns and requiring a minimum pulse width of 2µs for reliable reset assertion. Its internal 20kΩ pullup resistor allows direct connection to a momentary switch (MR to GND), eliminating external RC networks. When MR is pulled low, reset asserts immediately and remains active for the full 1.5ms timeout after MR returns high-ensuring µP reset completion even with noisy switch contacts.

Is the MAX6837VXSD0+ compatible with microcontrollers that have bidirectional reset pins, and how is this implemented?

Yes, the MAX6837VXSD0+ is explicitly designed for bidirectional µP reset pins due to its open-drain RESET output. Connect the MAX6837VXSD0+ RESET pin directly to the µP's reset I/O with a shared pullup resistor. Either device can then assert reset: the MAX6837VXSD0+ pulls low during brownout, and the µP pulls low during software-initiated reset. This eliminates level translators and simplifies PCB routing-confirmed in Maxim's Figure 4 application circuit for MAX6834/MAX6837/MAX6840.