Analog Devices Inc./Maxim Integrated MAX816CSA+T

Overview

MAX816CSA+T from Maxim Integrated is a ±1% accurate, low-power microprocessor supervisory circuit with adjustable reset threshold, active-high and active-low RESET outputs, power-fail monitoring (PFI/PFO), and manual reset input. It operates from 1.2V to 5.5V, guarantees valid RESET down to VCC = 1V, and draws only 75µA typical supply current. It is used in portable/battery-powered equipment and critical µP power monitoring where precise, glitch-immune reset control is required.

For engineers reviewing the MAX816CSA+T datasheet, MAX816CSA+T pinout, MAX816CSA+T application, or MAX816CSA+T equivalent, this page delivers verified functional identity, confirmed 8-pin SO package mapping, validated terminal roles (including RESET IN, PFI, PFO, MR), exact reset threshold adjustability via external divider, and two technically documented alternative parts for +3V supervisory use cases.

Technical Context

The MAX816CSA+T implements a high-impedance (≤35nA leakage) 1.700V reference comparator on the RESET IN pin to enable externally adjustable reset thresholds - unlike fixed-threshold MAX814/MAX815 variants. Its power-fail comparator uses a fixed 1.70V internal reference tied to PFI, driving open-drain PFO with ≥1.2mA sink capability.

It provides dual RESET outputs: active-low RESET (pin 7) and active-high RESET (pin 8), both asserted when RESET IN falls below 1.70V and held for ≥140ms after crossing back above threshold. No watchdog or LOW LINE functionality is present - distinguishing it from MAX814 (LOW LINE) and MAX815 (watchdog).

Key Specifications

Pinout & Package

MAX816CSA+T is housed in an 8-pin SO (Small Outline) package, surface-mount compatible, with 1.27mm lead pitch and JEDEC MS-012AC outline. Pin 1 is marked by a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX816CSA+T, MAX814TSA+ offers fixed-threshold simplicity and low-line detection but sacrifices adjustability and independent PFI monitoring; TPS3808G33DBVR reduces supply current by >95% but removes PFI, dual RESET, and reset timing flexibility - making MAX816CSA+T optimal for designs needing precision, configurability, and comprehensive power supervision.

Availability

MAX816CSA+T is available at Aetrix Electronics and suitable for portable medical devices, industrial PLCs, smart energy meters, and point-of-sale terminals requiring stable component supply across extended production lifecycles.

Supply support for MAX816CSA+T 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 demanding industrial, medical, and communications applications.

The MAX814/MAX815/MAX816 family was engineered specifically for high-accuracy, low-power microprocessor supervision in battery-constrained and mission-critical systems - with the MAX816 variant optimized for adjustable reset threshold and dual-output flexibility.

FAQ

What is the function of the RESET IN pin on the MAX816CSA+T?

The RESET IN pin on the MAX816CSA+T serves as the high-impedance (≤35nA leakage) input to a 1.700V reference comparator. It enables fully adjustable reset threshold via an external resistor divider - unlike fixed-threshold variants. When voltage at RESET IN falls below 1.700V, the MAX816CSA+T asserts both RESET outputs. This architecture decouples reset triggering from VCC, allowing monitoring of any voltage rail.

Does the MAX816CSA+T include a watchdog timer?

No, the MAX816CSA+T does not include a watchdog timer. Watchdog functionality is exclusive to the MAX815 series (e.g., MAX815CSA+T), which features WDI and WDO pins and a 1.56s timeout. The MAX816CSA+T is functionally aligned with the MAX814 series in omitting watchdog circuitry, focusing instead on adjustable reset and power-fail monitoring.

What is the PFI voltage threshold for the MAX816CSA+T, and how is it used?

The MAX816CSA+T has a fixed 1.70V PFI (Power-Fail Input) threshold. It is used to detect falling voltage on auxiliary rails - for example, connecting a resistor divider from a 12V supply to PFI so that PFO asserts when the divided voltage drops below 1.70V, signaling imminent failure. This enables µP-driven shutdown sequencing before main supply collapse.

Can the MAX816CSA+T operate with a 1.8V supply?

Yes, the MAX816CSA+T operates from 1.2V to 5.5V, so it functions reliably at 1.8V. However, its RESET outputs remain valid only down to VCC = 1V - meaning at 1.8V, both RESET and RESET outputs are fully functional. The 1.70V RESET IN reference and PFI threshold remain stable across this range, enabling accurate supervision even at low VCC.

How does the MAX816CSA+T differ from the MAX814CSA+T in pin configuration and functionality?

The MAX816CSA+T replaces the MAX814CSA+T's LOW LINE output (pin 6) with RESET IN (pin 6), removing low-line detection but enabling adjustable reset. Both share MR, VCC, GND, PFI, PFO, and dual RESET pins. Functionally, MAX816CSA+T cannot generate LOW LINE warnings, but gains full reset threshold programmability - making it suitable for custom voltage monitoring where fixed thresholds are insufficient.