Analog Devices Inc./Maxim Integrated MAX6835FXSD0+

Overview

MAX6835FXSD0+ from Maxim Integrated is an ultra-low-voltage microprocessor supervisory circuit in SC70-4 package, featuring a 1.050V factory-set reset threshold, push-pull active-low RESET output, debounced manual reset (MR) input, and 70µs reset timeout period. It monitors +1.2V to +1.8V supplies in portable battery-powered systems and asserts reset during brownout or power-up to ensure reliable µP initialization.

For engineers reviewing the MAX6835FXSD0+ datasheet, MAX6835FXSD0+ pinout, MAX6835FXSD0+ application, or MAX6835FXSD0+ equivalent, key selection criteria include its 1.050V threshold accuracy (±2.5%), 7.5µA typical supply current, guaranteed reset validity down to VCC = 0.55V, and compatibility with low-voltage core logic in space-constrained embedded designs.

Technical Context

The MAX6835FXSD0+ implements a precision bandgap-based voltage comparator with hysteresis (0.75% of VTH) to reject fast VCC transients, and integrates an internal 20kΩ MR pullup resistor enabling direct switch-to-ground connection without external components. Its reset assertion is triggered solely by VCC falling below 1.050V or MR being pulled low.

Reset remains asserted for exactly 70µs after VCC rises above 1.050V or MR is released, with propagation delay of 70µs and startup time of 150µs from 0V. The push-pull active-low RESET output sinks up to 200µA at VCC ≥ 1.5V while maintaining VOL ≤ 0.2V, ensuring clean interface with CMOS µP reset inputs.

Key Specifications

Pinout & Package

MAX6835FXSD0+ is housed in a 4-pin SC70-4 package (2.0mm × 2.1mm, 0.65mm pitch), optimized for high-density PCB layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6835FXSD0+, MAX809TRD1+T serves higher-voltage systems without manual reset, while TPS3808G01DBVR trades fixed low-current operation for timeout flexibility at higher power and BOM cost - MAX6835FXSD0+ uniquely balances 1.050V precision, 70µs speed, MR integration, and ultra-low 7.5µA consumption in SC70-4.

Availability

MAX6835FXSD0+ is available at Aetrix Electronics and suitable for portable medical devices, industrial wireless sensors, wearable health monitors, and low-power IoT edge controllers requiring stable component supply across extended production lifecycles.

Supply support for MAX6835FXSD0+ 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, sensing, and connectivity in demanding industrial and portable applications.

The MAX6832–MAX6840 family delivers ultra-low-voltage supervision for battery-powered systems, targeting applications where sub-1.2V supply monitoring, minimal quiescent current, and SC70 packaging are essential design constraints.

FAQ

What is the exact reset threshold voltage of the MAX6835FXSD0+ and how accurate is it over temperature?

The MAX6835FXSD0+ 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 confirmed in the Electrical Characteristics table of the official datasheet. The MAX6835FXSD0+ uses a precision bandgap reference and hysteresis (0.75% of VTH) to maintain stability against thermal drift and noise, making it suitable for reliable 1.2V system monitoring without calibration.

Does the MAX6835FXSD0+ require an external pullup resistor on its RESET pin?

No, the MAX6835FXSD0+ does not require an external pullup resistor because it features a push-pull active-low RESET output. This output actively drives LOW during reset and HIGH otherwise, eliminating dependency on external components. The MAX6835FXSD0+ can directly interface with standard CMOS µP reset inputs, unlike open-drain variants such as MAX6834FXRD0 which mandate a pullup. This reduces BOM count and improves signal integrity in compact layouts.

What is the function of the MR pin on the MAX6835FXSD0+ and how should it be used?

The MR (Manual Reset) pin on the MAX6835FXSD0+ is an active-low input with an internal 20kΩ pullup resistor to VCC. Pulling MR low forces an immediate reset, which remains asserted for the full 70µs timeout after MR returns high. It accepts CMOS-level signals and rejects glitches shorter than 100ns. For mechanical switch use, connect one side to MR and the other to GND - no external debounce circuitry is needed due to built-in filtering, simplifying field-service reset implementation.

Can the MAX6835FXSD0+ operate reliably when VCC drops below 1.0V?

Yes, the MAX6835FXSD0+ guarantees valid reset assertion down to VCC = 0.55V for its active-low push-pull output. Below this level, the RESET output becomes high-impedance, but the device continues monitoring and asserting reset until VCC falls out of specification. This behavior ensures deterministic µP reset during deep brownout conditions common in battery-depleted portable equipment, preventing undefined states in 1.2V logic systems before complete power loss.

What timeout period is implemented in the MAX6835FXSD0+ and how is it selected?

The MAX6835FXSD0+ implements a fixed 70µs reset active timeout period, denoted by the "D0" suffix in its ordering code. This value is factory-programmed and non-adjustable - no external components or configuration pins are required. The 70µs duration is optimized for fast power-up sequencing in modern low-power microcontrollers and matches the minimum reset-hold time specified in most 1.2V µP datasheets, ensuring robust initialization without unnecessary delay.