Analog Devices Inc./Maxim Integrated MAX6828SUT

Overview

MAX6828SUT from Maxim Integrated is an ultra-low-voltage dual microprocessor supervisory circuit in SOT23-6 package, monitoring primary supply (VCC) from +1.8V to +5.0V and user-adjustable secondary input (RESET IN) down to +0.63V, with 140ms minimum reset timeout, manual reset input (MR), and watchdog timer (WDI). It asserts an open-drain active-low RESET output during power-up, brownout, or software fault conditions in battery-powered embedded systems.

For engineers reviewing the MAX6828SUT datasheet, MAX6828SUT pinout, MAX6828SUT application, or MAX6828SUT equivalent, this page delivers verified electrical thresholds, reset timing behavior, watchdog interaction logic, and design-critical interface guidance for multivoltage µP systems requiring guaranteed reset validity down to VCC = +1.0V.

Technical Context

The MAX6828SUT implements a dual-threshold supervision architecture: one factory-trimmed VCC monitor and one high-impedance RESET IN comparator with typical 0.63V threshold, enabling user-defined secondary voltage monitoring via external resistor divider. Its internal 1.6s watchdog timer clears on any WDI edge or MR assertion and triggers reset if unrefreshed.

Reset assertion is synchronized across three independent sources-VCC falling below threshold, RESET IN falling below 0.63V, or WDI timeout-and held for ≥140ms after all conditions clear. The open-drain RESET output supports bidirectional µP reset pins (e.g., Motorola 68HC11) with external pullup, and operates reliably down to VCC = +1.0V without external support components.

Key Specifications

Pinout & Package

MAX6828SUT is housed in a 6-pin SOT23-6 package (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm, lead-free compatible, with gull-wing leads and thermal pad not connected internally.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6827SUT and MAX6316US29D3+, the MAX6828SUT uniquely combines open-drain reset for bidirectional µP compatibility, user-adjustable secondary monitoring, and integrated watchdog - making it the sole choice for compact multivoltage systems requiring fault-tolerant software supervision.

Availability

MAX6828SUT is available at Aetrix Electronics and suitable for portable/battery-powered equipment, embedded controllers, and intelligent instruments requiring stable component supply across industrial temperature range (-40°C to +125°C) and long-term production continuity.

Supply support for MAX6828SUT 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, automotive, and computing applications.

The MAX6826–MAX6831 family was designed specifically for ultra-low-voltage dual-rail microprocessor supervision in space-constrained, battery-sensitive systems - delivering integrated reset, watchdog, and manual reset functions in minimal 6-pin SOT23 packaging.

FAQ

What is the guaranteed operating VCC range for MAX6828SUT?

The MAX6828SUT is specified for VCC = +2.7V to +3.6V, corresponding to the 'S' threshold suffix. It guarantees correct reset assertion and timing behavior across this range and remains functional - including valid RESET output state - down to VCC = +1.0V, enabling robust brownout recovery in low-power systems where supply voltage may dip below nominal.

How does the RESET IN pin function on MAX6828SUT?

The RESET IN pin on MAX6828SUT is a high-impedance input with a typical threshold of +0.63V. It allows user-defined secondary voltage monitoring by connecting an external resistor divider from VCC to GND, with the divider midpoint fed to RESET IN. This enables precise supervision of voltages such as 1.2V, 1.8V, or 2.5V rails without requiring additional ICs - a capability confirmed in the Selector Guide and Electrical Characteristics table.

What is the watchdog timeout behavior of MAX6828SUT?

The MAX6828SUT features a nominal 1.6s watchdog timeout period, with min/max values of 1.12s and 2.4s over -40°C to +85°C. The internal timer clears on any WDI edge (rising or falling), MR assertion, or active RESET. If WDI remains static beyond the timeout, RESET asserts for the full reset timeout period (≥140ms). Leaving WDI unconnected disables the watchdog function.

Why does MAX6828SUT use an open-drain RESET output?

The MAX6828SUT uses an open-drain RESET output to support bidirectional microprocessor reset pins (e.g., Motorola 68HC11) and enable wired-OR reset buses where multiple supervisors or reset sources share a common reset line. An external pullup resistor sets the inactive state, while the MAX6828SUT actively pulls low during fault conditions - a design confirmed in the Applications Information section and Functional Diagram.

Is MAX6828SUT compatible with systems requiring reset assertion below VCC = +1.8V?

Yes. The MAX6828SUT is guaranteed to assert a valid RESET output down to VCC = +1.0V, as explicitly stated in the General Description and Absolute Maximum Ratings. This ensures reliable operation during deep brownout events where other supervisors may fail to detect undervoltage or assert reset - a key differentiator for ultra-low-voltage embedded applications.