Analog Devices Inc./Maxim Integrated MAX815KCPA+

Overview

MAX815KCPA+ from Maxim Integrated is a high-accuracy, low-power microprocessor supervisory IC with integrated watchdog timer, power-fail monitoring, and active-low reset output. It features a 4.8V ±1% 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 system recovery.

For engineers reviewing the MAX815KCPA+ datasheet, MAX815KCPA+ pinout, MAX815KCPA+ application, or MAX815KCPA+ equivalent, key selection criteria include its fixed 4.8V reset threshold, independent 1.56s watchdog timeout, PFI/PFO undervoltage warning capability, manual reset input (MR), and compatibility with +5V systems operating from 4.85V to 5.5V.

Technical Context

The MAX815KCPA+ implements a dedicated watchdog timer with 1.56s timeout triggered by WDI transitions - not voltage monitoring - enabling software execution supervision independent of VCC stability. Its reset generator uses a precision bandgap reference and comparator with ±1% worst-case accuracy over temperature and supply variation.

Power-fail detection is handled by a separate 2.50V PFI comparator (K-suffix), driving open-drain PFO to signal early supply degradation. The MR input includes a 150µA internal pullup and supports TTL/CMOS logic levels, while RESET remains asserted for ≥200ms after MR release.

Key Specifications

Pinout & Package

MAX815KCPA+ is housed in an 8-pin plastic DIP package (PDIP) with 0.3-inch body width and through-hole mounting. Pin 1 is marked with a notch or dot; pin numbering proceeds counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX815KCPA+, MAX814KCPA+ removes watchdog complexity while adding low-line detection for battery-aware systems, whereas TPS3808G33DBVR trades accuracy, dual-rail support, and feature richness for lower cost and simpler integration in basic 3.3V reset applications.

Availability

MAX815KCPA+ is available at Aetrix Electronics and suitable for medical instrumentation, portable diagnostic controllers, industrial PLCs, set-top boxes, and intelligent instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX815KCPA+ 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, emphasizing reliability, accuracy, and low power.

The MAX814/MAX815/MAX816 family was engineered specifically for high-reliability microprocessor supervision in portable and critical systems, combining ±1% reset accuracy, ultra-low quiescent current, and integrated watchdog/power-fail functions in compact 8-pin packages.

FAQ

What is the reset threshold voltage of the MAX815KCPA+?

The MAX815KCPA+ has a factory-set reset threshold of 4.80V ±1%, meaning the guaranteed minimum trip point is 4.75V under worst-case conditions. This threshold is optimized for +5V systems with ±4% supply tolerance and ensures reliable reset assertion before µP operational voltage limits are violated. The "K" suffix explicitly denotes this 4.8V rating per Maxim's ordering nomenclature.

Does the MAX815KCPA+ include a watchdog timer?

Yes, the MAX815KCPA+ integrates a fully independent watchdog timer with a nominal timeout period of 1.56 seconds. It monitors the WDI pin for transitions - not VCC - and asserts WDO low if no edge occurs within that window. This function is exclusive to the MAX815 variant; MAX814 and MAX816 lack it. WDO can be connected to MR to generate a full system reset on timeout.

Can the MAX815KCPA+ monitor voltages other than VCC?

Yes, the MAX815KCPA+ can monitor auxiliary supply rails using the PFI pin. With its fixed 2.50V internal reference, an external resistor divider scales the target voltage (e.g., +12V) to fall below 2.50V just before the rail becomes unsafe. When PFI drops below threshold, PFO pulls low to trigger a µP interrupt, enabling early shutdown sequencing - a capability confirmed in Figures 1 and 11 of the official datasheet.

What is the supply current specification for the MAX815KCPA+?

The MAX815KCPA+ draws a maximum supply current of 75µA across its full operating temperature range (0°C to +70°C) and VCC range (4.85V to 5.5V). Typical current is lower - approximately 45µA at +25°C and VCC = 5.0V - making it suitable for battery-critical applications like portable medical devices where multi-year shelf life is required without compromising reset accuracy or watchdog responsiveness.

How does the manual reset (MR) input behave on the MAX815KCPA+?

The MR input on the MAX815KCPA+ is an active-low, internally pulled up (150µA) CMOS-compatible pin. Pulling MR below 1.10V asserts RESET immediately; RESET remains low for at least 200ms after MR returns high. No external pullup is needed, and MR accepts standard TTL/CMOS logic levels. Debounce is unnecessary for momentary switch use, though a 0.1µF capacitor to ground is recommended in noisy environments.