Analog Devices Inc./Maxim Integrated MAX802MCPA+

Overview

MAX802MCPA+ from Maxim Integrated is a microprocessor supervisory IC providing 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), delivers VOUT from VCC or VBATT with 40mV hysteresis, and features PFI/PFO comparator with 1.25V threshold - used in industrial controllers and battery-backed memory systems.

For engineers reviewing the MAX802MCPA+ datasheet, MAX802MCPA+ pinout, MAX802MCPA+ application, or MAX802MCPA+ equivalent, key selection criteria include its 4.40V reset threshold, 200ms reset pulse width, 50nA battery-backup quiescent current, guaranteed RESET assertion down to VCC = 1V, and compatibility with lithium backup batteries up to 4.55V.

Technical Context

The MAX802MCPA+ integrates four core functions on a single die: a precision voltage monitor with 4.40V ±2% reset threshold, a 1.6s watchdog timer cleared by WDI edges or RESET assertion, a bidirectional battery switchover circuit with 80Ω PMOS switch and 40mV hysteresis, and an independent 1.25V reference-based power-fail comparator driving PFO.

Its internal architecture isolates the PFI comparator from reset logic, enabling flexible undervoltage monitoring of non-5V rails. The RESET output remains valid down to VCC = 1V, and VOUT sourcing supports CMOS RAM retention during main supply failure - all while drawing only 200µA in normal operation and 50nA in battery-backup mode.

Key Specifications

Pinout & Package

MAX802MCPA+ is housed in an 8-pin plastic DIP package (0.300" wide) with industry-standard lead spacing and RoHS-compliant lead-free finish (+ suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX802MCPA+, MAX802MCSA+ offers identical functionality in surface-mount form for density-critical layouts, while MAX800MCPA+ adds watchdog flexibility at the cost of reduced low-VCC reset guarantee - making MAX802MCPA+ optimal for fixed-timing, high-reliability industrial control.

Availability

MAX802MCPA+ is available at Aetrix Electronics and suitable for industrial programmable logic controllers, smart energy meters, medical infusion pumps, and ruggedized handheld terminals requiring stable component supply across extended temperature ranges and long production lifecycles.

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 precision analog and mixed-signal ICs for industrial, medical, and communications applications, emphasizing reliability, low power, and integration.

The MAX802MCPA+ belongs to Maxim's microprocessor supervisory product line, engineered specifically for fail-safe power monitoring and battery-backed memory retention in harsh environments where supply stability cannot be assumed.

FAQ

What is the guaranteed minimum VCC level at which MAX802MCPA+ asserts RESET?

The MAX802MCPA+ guarantees RESET assertion down to VCC = 1V across its operating temperature range. This ensures the microprocessor remains held in reset even during deep brownout conditions where other supervisory ICs may release prematurely. The specification is verified per Electrical Characteristics table, with RESET output voltage maintained below 0.4V at ISINK = 3.2mA when VCC = 1.2V for the E-grade variant - and explicitly confirmed for C-grade MAX802MCPA+ in the Detailed Description section.

Can MAX802MCPA+ monitor a +3.3V supply instead of +5V?

Yes, MAX802MCPA+ can monitor a +3.3V supply using its PFI input and internal 1.25V reference. Connect a resistor divider from the +3.3V rail to PFI so that PFI = 1.25V when the supply reaches its undervoltage threshold (e.g., 3.0V). The PFI input draws only ±25nA, minimizing divider error. Note that the primary reset function remains tied to VCC, so VCC must still be supplied with a valid +5V rail for the IC to operate.

What is the maximum allowable VBATT voltage for MAX802MCPA+?

The maximum allowable VBATT voltage for MAX802MCPA+ is 4.55V, as specified in Table 2 of the datasheet. Exceeding this risks forward-biasing the internal substrate diode (D1 in Figure 3) when VCC is near its reset threshold, causing unintended current flow from VBATT into the VCC domain and potential latch-up. Lithium coin cells (3.0–3.6V) and SuperCaps charged to ≤4.55V comply safely.

Does MAX802MCPA+ require external components to function as a basic supervisor?

No, MAX802MCPA+ operates autonomously with no external components required for core reset, watchdog, and battery switchover functions. Only optional features need external parts: a resistor divider for PFI (if monitoring non-5V rails), a pull-up resistor for PFO (open-drain output), and a capacitor on WDI (if noise filtering is needed). The device includes internal 1.25V reference, precision voltage comparators, and MOSFET switches.

How does the watchdog timer interact with the RESET signal in MAX802MCPA+?

In MAX802MCPA+, the watchdog timer and RESET are tightly coupled: a 1.6s timeout on WDI triggers an immediate RESET pulse, and any active RESET assertion clears the watchdog timer. The timer restarts only after RESET goes high and WDI receives a valid edge. This prevents spurious timeouts during reset recovery and ensures the watchdog remains disabled while the system is held in reset - a critical safety feature for fault-tolerant designs.