Analog Devices Inc./Maxim Integrated MAX816CSA

Overview

MAX816CSA from Maxim Integrated is a high-accuracy, low-power microprocessor supervisory circuit with adjustable reset threshold, power-fail monitoring, and manual reset input. It provides active-low RESET output, guarantees valid reset assertion down to VCC = 1V, and draws only 75µA typical supply current. Designed for +3V systems (3.06V–5.5V operation), it serves in battery-powered medical instruments and portable controllers requiring precise brownout detection.

For engineers reviewing the MAX816CSA datasheet, MAX816CSA pinout, MAX816CSA application, or MAX816CSA equivalent, this page delivers verified functional identity, confirmed pin roles, exact reset threshold configuration method, power-fail comparator reference voltage (1.70V), and validated alternative options for 3V µP supervision.

Technical Context

The MAX816CSA uses an external resistive divider on the RESET IN pin (1.700V internal reference) to set its reset threshold - unlike fixed-threshold MAX814/MAX815 variants. Its PFI input compares against a stable 1.70V reference, and PFO asserts low when PFI falls below that level. The device lacks watchdog functionality but includes a manual reset input (MR) with 150µA internal pull-up and guaranteed 200ms reset pulse width.

RESET is controlled solely by the RESET IN pin voltage-not VCC-enabling independent monitoring of auxiliary rails. The low-line detector and WDO features present in MAX814/MAX815 are absent; instead, MAX816CSA prioritizes flexibility and precision in reset threshold programming for 3V/3.3V applications across commercial temperature range (0°C to +70°C).

Key Specifications

Pinout & Package

MAX816CSA is housed in an 8-pin SO (Small Outline) package, surface-mount compatible with standard reflow profiles. Pin 1 is marked with a beveled corner or dot; pin numbering follows counterclockwise convention from top-left when viewing the top side.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX816CSA, MAX814TSA offers simpler implementation at the cost of inflexibility, while TPS3808G33DBVR delivers superior accuracy and temperature range but sacrifices adjustability and requires layout revision.

Availability

MAX816CSA is available at Aetrix Electronics and suitable for medical instrumentation, portable diagnostic devices, industrial controllers, and smart sensor nodes requiring stable component supply and long-term manufacturability.

Supply support for MAX816CSA 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 targets µP supervision in space-constrained, battery-sensitive systems where accuracy, low IQ, and flexible reset configuration are essential - especially in 3V/3.3V domains.

FAQ

What is the reset threshold configuration method for MAX816CSA?

The MAX816CSA does not have a fixed reset threshold. Instead, it uses an external resistive divider connected to the RESET IN pin, which references an internal 1.700V comparator. By selecting R1 and R2 values per the formula VRT = VRIT × (1 + R1/R2), designers set the exact trip point - enabling precise adaptation to system-specific supply tolerances without changing the MAX816CSA part number.

Does MAX816CSA include a watchdog timer function?

No, MAX816CSA does not include a watchdog timer. That feature is exclusive to the MAX815 variant. MAX816CSA focuses on adjustable reset supervision and power-fail monitoring. If watchdog capability is required, MAX815CSA (with 1.56s timeout) or MAX814CSA (no watchdog, fixed thresholds) should be evaluated instead - both share the same 8-pin SO package but differ in internal functionality.

What is the PFI reference voltage for MAX816CSA, and how is it used?

The PFI reference voltage for MAX816CSA is 1.70V ±2%. This internal comparator reference allows designers to monitor any DC voltage - including 3.3V rails, battery voltages, or isolated supplies - by connecting a resistive divider to PFI. When the divided voltage drops below 1.70V, PFO pulls low to signal impending power failure, enabling µP-initiated data save or controlled shutdown before reset occurs.

Can MAX816CSA operate with a 2.8V supply?

No, MAX816CSA requires a minimum VCC of 3.06V per its electrical specifications. Operation below this voltage violates absolute maximum ratings and may result in undefined behavior or failure to assert RESET correctly. For sub-3V applications, consider alternatives like the MAX6326 series (1.8V–5.5V) or TPS3801 family, which explicitly specify operation down to 1.8V or lower.

Is the RESET output of MAX816CSA push-pull or open-drain?

The RESET output of MAX816CSA is open-drain, active-low. It requires an external pull-up resistor to VCC or another logic rail. This configuration allows wired-OR connection with other reset sources and supports mixed-voltage interface designs. The datasheet specifies VOL ≤ 0.4V at ISINK = 3.2mA, confirming robust low-state drive capability within its specified operating range.