Analog Devices Inc./Maxim Integrated MAX811TEUS

Overview

MAX811TEUS from Maxim Integrated is an active-low microprocessor supervisory circuit in a 4-pin SOT143 package, designed to monitor 3.08V supply rails and assert reset during power-up, brownout, or power-down events. It delivers 6µA supply current, guarantees RESET validity down to VCC = 1V, and provides 140ms minimum reset timeout-ideal for battery-powered embedded controllers requiring reliable power-on initialization.

For engineers reviewing the MAX811TEUS datasheet, MAX811TEUS pinout, MAX811TEUS application, or MAX811TEUS equivalent, key selection criteria include its precise 3.08V threshold (±1.5% over temperature), manual reset input with 20kΩ internal pull-up, immunity to sub-40µs VCC transients, and guaranteed operation across –40°C to +85°C industrial temperature range.

Technical Context

The MAX811TEUS implements a precision bandgap-based voltage comparator with factory-trimmed 3.08V reset threshold and 30ppm/°C tempco, ensuring accurate detection of 3V ±5% supply regulation loss. Its internal timer generates a fixed 140ms reset pulse after VCC rises above threshold, independent of supply ramp rate.

It features a debounced manual reset input (MR) with 10µs glitch immunity and 10µs minimum pulse width requirement; MR asserts reset low while held low and maintains it for 180ms after release. The active-low RESET output sinks up to 1.2mA at VCC ≥ VTH(MIN), with VOL ≤ 0.4V under load.

Key Specifications

Pinout & Package

MAX811TEUS is housed in a 4-pin SOT143 package (4.0 × 2.0 × 1.75 mm), surface-mountable with gull-wing leads. Pin 1 is VCC, Pin 2 is GND, Pin 3 is RESET (active-low open-drain), and Pin 4 is MR (active-low manual reset input).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G30DBVR and ADM6705ARTZ-REEL7, the MAX811TEUS offers integrated MR pull-up and guaranteed RESET validity down to VCC = 1V-critical for brownout resilience in 3V battery systems-while trading off slightly higher supply current and shorter reset timeout.

Availability

MAX811TEUS is available at Aetrix Electronics and suitable for industrial controllers, portable medical devices, smart sensor nodes, and point-of-sale terminals requiring stable component supply with guaranteed long-term availability.

Supply support for MAX811TEUS 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 interface applications in industrial, automotive, and communications markets.

The MAX811/MAX812 family was engineered specifically for cost-sensitive, space-constrained µP systems needing single-chip voltage supervision with manual reset-targeting portable, battery-powered, and embedded control equipment.

FAQ

What is the exact reset threshold voltage for MAX811TEUS?

The MAX811TEUS has a nominal reset threshold voltage of 3.08V, with guaranteed accuracy of ±1.5% over the full –40°C to +85°C temperature range. This value is factory-trimmed and specified in the Electrical Characteristics table under VTH parameter for the 'T' suffix variant. The threshold remains stable with a tempco of 30ppm/°C, making it suitable for precise 3V supply monitoring in industrial applications.

Does MAX811TEUS require external components for basic operation?

No, the MAX811TEUS requires no external components for core supervision functionality. Its internal 20kΩ pull-up resistor on the MR pin allows direct connection of a momentary switch to ground. The active-low RESET output is open-drain and only needs an external pull-up resistor (typically 10kΩ) to interface with most µP reset inputs. No timing capacitors or voltage dividers are necessary-enabling true single-chip reset solution.

How does MAX811TEUS behave when VCC drops below 1V?

The MAX811TEUS guarantees correct RESET output state down to VCC = 1V: RESET remains a valid logic low (sinking up to 1.2mA) throughout this range. Below 1V, the RESET output transitions to high-impedance (open-circuit) mode. To maintain a defined low state down to 0V, a 100kΩ external pull-down resistor on the RESET pin is recommended per Maxim's Application Information section.

What is the minimum pulse width required on the MR pin to trigger reset?

The MAX811TEUS requires a minimum MR pulse width of 10µs to reliably initiate a reset event. This specification is documented in the Electrical Characteristics table under "MR Minimum Pulse Width (tMR)" with a typical value of 10µs. Pulses shorter than this may not be recognized due to internal glitch filtering, which rejects transients ≤100ns-ensuring noise immunity in electrically harsh environments.

Can MAX811TEUS be used with 3.3V microcontrollers that have bidirectional reset pins?

Yes, but with caution: MAX811TEUS can interface with bidirectional µP reset pins (e.g., Motorola 68HC11) using a 4.7kΩ series resistor between RESET and the µP pin, as shown in Figure 3 of the datasheet. This prevents contention when both devices drive the line. Without this resistor, simultaneous high-drive from the µP and low-drive from MAX811TEUS could cause indeterminate logic levels or excessive current flow.