Analog Devices Inc./Maxim Integrated MAX6836FXSD3+

Overview

MAX6836FXSD3+ from Maxim Integrated is a push-pull active-high microprocessor supervisory circuit designed to monitor +1.2V to +1.8V supply rails in low-voltage digital systems. It asserts RESET when VCC falls below 1.050V (±2.5% over temperature), maintains reset for 210ms after recovery, and draws only 7.5µA typical supply current - enabling reliable power-on reset in portable battery-powered equipment.

For engineers reviewing the MAX6836FXSD3+ datasheet, MAX6836FXSD3+ pinout, MAX6836FXSD3+ application, or MAX6836FXSD3+ equivalent, key selection criteria include its factory-set 1.050V reset threshold, 210ms timeout period (D3 suffix), SC70-4 package, debounced MR input, and guaranteed RESET validity down to VCC = 0.75V.

Technical Context

The MAX6836FXSD3+ implements a precision bandgap-based voltage comparator with ±2.5% threshold accuracy across –40°C to +85°C, paired with a fixed 210ms reset timeout timer. Its internal 20kΩ MR pullup enables direct connection of a momentary switch to ground without external debounce circuitry.

This device uses BiCMOS process technology (681 transistors) and features immunity to short negative VCC transients ≤100ns, while asserting RESET only when VCC drops below 1.050V or MR is pulled low - ensuring robust operation during brownout and power-up sequencing.

Key Specifications

Pinout & Package

MAX6836FXSD3+ is housed in a 4-pin SC70 package (1.3mm × 1.6mm, 0.5mm pitch), optimized for high-density portable designs. Pin 1 is GND, Pin 2 is RESET (push-pull active-high), Pin 3 is MR (active-low manual reset), and Pin 4 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6836FXSD3+, MAX6316HUT46+T serves higher-voltage systems but cannot monitor 1.2V rails, while TPS3808G33DBVR offers flexibility at the cost of added components and 60% higher supply current - making MAX6836FXSD3+ optimal for compact, low-power 1.2V–1.8V applications.

Availability

MAX6836FXSD3+ is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered IoT nodes, and industrial PLC I/O modules requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6836FXSD3+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, computing, and communications markets.

The MAX6832–MAX6840 product line delivers ultra-low-voltage supervisory circuits targeting portable and battery-operated systems requiring precise reset control at 1.2V–1.8V supply levels with minimal quiescent current.

FAQ

What is the exact reset threshold voltage for MAX6836FXSD3+ and how accurate is it over temperature?

The MAX6836FXSD3+ has a factory-set reset threshold of 1.050V 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, ensuring consistent brownout detection for 1.2V systems without calibration or external components. The threshold is referenced internally to a precision bandgap, not to VCC, so it remains stable even as supply voltage varies.

Does MAX6836FXSD3+ support manual reset, and what are the electrical requirements for the MR pin?

Yes, MAX6836FXSD3+ includes a debounced manual reset (MR) input with an internal 20kΩ pullup resistor to VCC. To assert reset, MR must be driven below 0.3×VCC for ≥2µs. The pin accepts CMOS-level signals and is compatible with open-drain drivers. No external components are needed - a simple momentary switch from MR to ground suffices, and the internal debounce eliminates need for RC filters or firmware handling.

What is the function of the RESET output on MAX6836FXSD3+, and how does it interface with microprocessors?

The RESET output of MAX6836FXSD3+ is a push-pull, active-high signal that drives HIGH during reset and LOW otherwise. It is designed for direct connection to microprocessors requiring HIGH-active reset inputs (e.g., many ARM Cortex-M and RISC-V MCUs). With 0.2×VCC VOL at 200µA sink and 0.8×VCC VOH at 150µA source, it meets standard CMOS logic thresholds across its 0.75V–3.6V VCC range, eliminating need for level shifters or pullup resistors.

How does MAX6836FXSD3+ behave when VCC falls below 0.75V, and is RESET still valid?

MAX6836FXSD3+ guarantees RESET output validity down to VCC = 0.75V - meaning the active-high RESET signal remains asserted and electrically valid (VOH ≥ 0.8×VCC) until VCC drops to that level. Below 0.75V, the output may become indeterminate. For applications requiring reset assertion all the way to 0V, a 100kΩ pullup resistor to VCC is recommended to maintain defined logic state, as documented in Maxim's application note for this device family.

What timeout period is implemented in MAX6836FXSD3+, and how is it selected?

MAX6836FXSD3+ implements a fixed 210ms reset timeout period, indicated by the "D3" suffix in its ordering code. This timeout is factory-programmed and non-adjustable - it begins when VCC rises above 1.050V or when MR is released, and holds RESET HIGH for exactly 210ms thereafter. The timing is generated by an internal RC oscillator calibrated to ±20% over temperature, eliminating need for external capacitors or trimming.