Analog Devices Inc./Maxim Integrated MAX815LCSA+T

Overview

MAX815LCSA+T from Maxim Integrated is a ±1% accurate, low-power microprocessor supervisory circuit with integrated watchdog timer, power-fail monitoring, and active-low reset output. It features a 4.7V fixed reset threshold, 200ms reset timeout, 75µA max supply current, and guaranteed RESET validity down to VCC = 1V. It is used in portable medical instruments and battery-powered controllers requiring reliable brownout detection and autonomous watchdog recovery.

For engineers reviewing the MAX815LCSA+T datasheet, MAX815LCSA+T pinout, MAX815LCSA+T application, or MAX815LCSA+T equivalent, this page delivers verified functional identity, exact pin roles for SO-8 layout, confirmed +5V system compatibility (4.75V–5.5V operating range), and two validated alternative supervisory ICs with documented threshold and watchdog differences.

Technical Context

The MAX815LCSA+T implements a dedicated watchdog timer with 1.56s timeout triggered by WDI transitions, independent of the VCC reset comparator. Its reset generator asserts active-low RESET for ≥200ms after VCC rises above 4.7V or MR falls below 1.1V, with immunity to transients ≤30µs at 100mV overdrive.

Power-fail monitoring uses a 2.50V internal reference on PFI (K/L/N variants), driving open-drain PFO low when input drops below threshold; the LOW LINE output is absent - confirming MAX815-specific omission versus MAX814. All logic interfaces (MR, WDI, PFI) accept CMOS/TTL levels and feature internal 150µA pull-up on MR.

Key Specifications

Pinout & Package

MAX815LCSA+T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant and lead-free (+T suffix). Pin 1 is marked with a dot or bevel; pin count and spacing conform to JEDEC MS-012AA standard (150 mil width, 1.27mm pitch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX815LCSA+T, MAX814LCSA+T removes watchdog capability but adds low-line warning for predictive brownout response, while TPS3808G33DBVR trades functionality for extreme low-power operation at the cost of 5V compatibility and supervision flexibility.

Availability

MAX815LCSA+T is available at Aetrix Electronics and suitable for medical portable monitors, battery-powered controllers, intelligent set-top boxes, and critical µP power monitoring applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX815LCSA+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, with emphasis on reliability and parametric accuracy.

The MAX814/MAX815/MAX816 family was engineered specifically for high-accuracy µP supervision in safety-critical and portable systems, combining reset, watchdog, and power-fail functions in minimal footprint with guaranteed behavior down to 1V VCC.

FAQ

What is the reset threshold voltage of the MAX815LCSA+T?

The MAX815LCSA+T has a factory-trimmed reset threshold of 4.70V ±1%, optimized for +5V systems with ±5% supply tolerance. This value is fixed and defined by the "L" suffix per Maxim's ordering convention; it ensures reset assertion before the µP's minimum operating voltage is violated under worst-case temperature and load conditions.

Does the MAX815LCSA+T include a watchdog timer?

Yes, the MAX815LCSA+T integrates a dedicated watchdog timer with a nominal timeout period of 1.56 seconds. It is triggered by transitions on the WDI pin and operates independently of the VCC reset comparator; WDO asserts low on timeout or during VCC reset, providing autonomous recovery from firmware lockups.

What is the function of the PFI and PFO pins on the MAX815LCSA+T?

PFI is the power-fail input referenced to a 2.50V internal comparator; when voltage at PFI falls below 2.50V, PFO - an open-drain output - pulls low and can sink ≥1.2mA. This enables early warning of +5V rail collapse using an external resistor divider, allowing the µP to initiate orderly shutdown before RESET activates.

Can the MAX815LCSA+T operate with a 3.3V supply?

No, the MAX815LCSA+T is specified only for 4.75V to 5.5V operation and uses a 4.7V reset threshold. For 3.3V systems, the MAX815T variant (3.03V threshold) or MAX816 (adjustable threshold) should be selected; substituting MAX815LCSA+T on 3.3V will prevent proper reset assertion and likely cause system instability.

Is the RESET output of the MAX815LCSA+T push-pull or open-drain?

The RESET output of the MAX815LCSA+T is a push-pull (active driver) structure, capable of both sourcing and sinking current. It drives low to ≤0.4V at 3.2mA and high to VCC −1.5V at 800µA, allowing direct connection to most µP reset inputs without external pull-up resistors.