Analog Devices Inc./Maxim Integrated MAX802MCPA

Overview

MAX802MCPA from Maxim Integrated is a microprocessor supervisory IC providing precision reset generation, battery-backup switchover, watchdog timer, and power-fail detection for +5V systems. It asserts active-low RESET during power-up, brownout (VCC < 4.40V), and watchdog timeout (1.6s), while switching VOUT to VBATT when VCC drops below threshold-used in battery-powered controllers and intelligent instruments requiring reliable μP startup and data retention.

For engineers reviewing the MAX802MCPA datasheet, MAX802MCPA pinout, MAX802MCPA application, or MAX802MCPA equivalent, key selection criteria include its 4.40V reset threshold, ±2% power-fail accuracy, 200ms reset pulse width, 50nA battery-backup quiescent current, and compatibility with CMOS RAM backup in industrial embedded systems.

Technical Context

The MAX802MCPA integrates four core functions: a precision voltage monitor with 4.40V reset threshold (±2% over temperature), a 1.6s watchdog timer cleared by WDI edges, a battery switchover circuit using 80Ω PMOS switch with 40mV hysteresis, and a 1.25V reference-based power-fail comparator driving PFO.

Its internal architecture guarantees RESET assertion down to VCC = 1V, supports manual reset disable via floating WDI, and disables the PFI comparator when VBATT powers VOUT-ensuring minimal battery drain during backup mode while maintaining fast response (<400ns) on power-fail detection.

Key Specifications

Pinout & Package

MAX802MCPA is housed in an 8-pin plastic DIP (PDIP) package with 0.3-inch width, RoHS-compliant lead finish, and standard through-hole mounting. Pin 1 is VBATT, pin 8 is GND, and all pins are electrically defined per Maxim's official pin description table.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX802LCPA and MAX706PESA, MAX802MCPA uniquely combines 4.40V precision reset, battery switchover, and power-fail warning in a single PDIP package-making it irreplaceable in legacy +5V battery-backed μP systems requiring all three functions.

Availability

MAX802MCPA is available at Aetrix Electronics and suitable for battery-powered controllers, intelligent instruments, and critical μP power monitoring requiring stable component supply across industrial temperature ranges and long-lifecycle programs.

Supply support for MAX802MCPA 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 high-performance analog and mixed-signal ICs for industrial, communications, and computing applications.

The MAX802MCPA belongs to Maxim's μP supervisory circuit family, engineered specifically to replace discrete reset generators and battery switchover circuits in +5V microprocessor systems with guaranteed timing, accuracy, and reliability.

FAQ

What is the reset threshold voltage for MAX802MCPA?

The MAX802MCPA has a nominal reset threshold of 4.40V, with a guaranteed range of 4.25V to 4.50V over temperature. This value is specified for VCC falling conditions and includes 40mV hysteresis to prevent chatter during slow supply decay. The threshold is factory-trimmed and does not require external calibration-enabling direct replacement of discrete reset circuits in +5V systems.

Does MAX802MCPA support battery backup for CMOS RAM?

Yes, MAX802MCPA provides integrated battery-backup switchover for CMOS RAM. When VCC falls below 4.40V, it automatically connects VBATT to VOUT through an 80Ω PMOS switch-provided VBATT exceeds VCC by at least 20mV. In backup mode, MAX802MCPA draws only 50nA from the battery at +25°C, ensuring multi-year operation with standard lithium coin cells.

How does the watchdog timer function in MAX802MCPA?

The MAX802MCPA watchdog timer times out after 1.6 seconds if the WDI pin is held static (high or low). A rising or falling edge on WDI clears the timer. The timer also resets automatically during RESET assertion or when WDI is left floating (high-impedance). This behavior allows flexible firmware supervision without requiring constant toggling-ideal for low-power sleep modes where wake events are infrequent.

What is the purpose of the PFI and PFO pins on MAX802MCPA?

PFI is the power-fail comparator input referenced to an internal 1.25V bandgap; when the voltage at PFI drops below 1.25V, PFO goes low to signal impending supply failure. PFO is an open-drain output that can drive a μP interrupt line or external logic. During battery backup (VBATT powering VOUT), the PFI comparator is disabled and PFO is forced low-eliminating unnecessary current draw from the backup source.

Can MAX802MCPA operate with VCC below 4.40V and still assert RESET?

Yes, MAX802MCPA guarantees RESET assertion down to VCC = 1.0V, per its Absolute Maximum Ratings and Electrical Characteristics table. As VCC falls below 4.40V, RESET remains low for 200ms after crossing the threshold-and continues asserting as long as VCC stays below 1.0V. This ensures μP remains held in reset throughout deep brownout, preventing erratic execution during unstable supply conditions.