Analog Devices Inc./Maxim Integrated MAX802LCPA+

Overview

MAX802LCPA+ from Maxim Integrated is a microprocessor supervisory IC providing reset generation, battery-backup switching, watchdog timer, and power-fail detection in a single 8-pin DIP package. It asserts a low-active RESET pulse during power-up (VCC ≥ 1V), brownout (VCC < 4.65V), and watchdog timeout (1.6s), while delivering VOUT from VCC or VBATT with ±2% power-fail accuracy - used in battery-powered controllers requiring reliable μP startup and RAM retention.

For engineers reviewing the MAX802LCPA+ datasheet, MAX802LCPA+ pinout, MAX802LCPA+ application, or MAX802LCPA+ equivalent, this page delivers verified specifications, validated pin functions, confirmed alternative parts for 4.65V reset threshold supervisory circuits, and supply-chain support for industrial embedded designs.

Technical Context

The MAX802LCPA+ integrates four independent functional blocks: a precision 4.65V reset comparator with 200ms pulse width and guaranteed assertion down to VCC = 1V; a 1.6s watchdog timer cleared by WDI edge transitions; a battery switchover circuit using 5Ω (VCC-on) and 80Ω (VBATT-on) PMOS switches; and a 1.25V reference-based power-fail comparator (PFI/PFO) with 400ns response time and ±2% accuracy over temperature.

Its dual-supply architecture enables seamless transition between VCC and VBATT when VCC drops below 4.65V (with 40mV hysteresis), while quiescent current remains at 200μA in normal operation and drops to 50nA in battery-backup mode - critical for long-life lithium-backed systems where supply integrity and low leakage are co-constrained.

Key Specifications

Pinout & Package

MAX802LCPA+ uses an 8-pin plastic DIP (PDIP) package with 0.3-inch width and through-hole mounting. Pin spacing conforms to JEDEC MS-001, compatible with standard PCB footprints for legacy μP supervisory circuits.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX802LEPA+, MAX802LCPA+ offers identical electrical performance at lower cost and lead time for commercial-temperature applications; compared with MAX805LCPA+, it provides the industry-standard active-low reset polarity required by most 8-bit and 32-bit microcontrollers without level-shifting.

Availability

MAX802LCPA+ is available at Aetrix Electronics and suitable for battery-powered controllers, intelligent instruments, critical μP power monitoring, and embedded data loggers requiring stable component supply across production lifecycles.

Supply support for MAX802LCPA+ 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, with emphasis on reliability, integration, and low-power operation.

The MAX802LCPA+ belongs to Maxim's μP supervisory product line, engineered specifically to replace discrete reset generators, battery switches, and watchdog timers in space-constrained embedded systems operating from +5V rails.

FAQ

What is the guaranteed reset assertion voltage for MAX802LCPA+?

The MAX802LCPA+ guarantees RESET output remains a valid logic low down to VCC = 1.0V, ensuring deterministic reset behavior during deep brownout conditions. This specification is tested and guaranteed across the full 0°C to +70°C operating temperature range, and is critical for systems where the +5V supply may sag significantly before complete failure. The MAX802LCPA+ achieves this using a dedicated low-voltage comparator stage independent of the main reset threshold circuitry.

Does MAX802LCPA+ support lithium battery backup without external components?

Yes, MAX802LCPA+ supports direct connection of 3.0V–3.6V lithium batteries to the VBATT pin without external diodes or regulators. Its internal switchover circuit engages only when VCC falls below 4.65V and VBATT exceeds VCC by ≥20mV, and draws <1μA from the battery when VCC is >1V below VBATT. The device also guarantees ±2% power-fail accuracy, enabling precise low-battery warning using the PFI/PFO pair.

How does the watchdog timer in MAX802LCPA+ interact with the reset function?

The MAX802LCPA+ watchdog timer triggers a full 200ms RESET pulse if the WDI pin remains static (high or low) for 1.6s. The timer clears on any rising or falling edge at WDI, on RESET assertion, or when WDI is three-stated. Critically, while RESET is asserted, the watchdog remains disabled - preventing spurious timeouts during reset recovery. This behavior ensures that firmware-initiated resets do not inadvertently trigger secondary watchdog events.

Can MAX802LCPA+ monitor a negative supply rail?

Yes, MAX802LCPA+ can monitor negative rails using an external resistor network that references the PFI input to ground. As shown in Figure 7 of the datasheet, connecting R1 and R2 between the negative rail and GND creates a positive voltage at PFI proportional to |V−|; when that voltage drops below 1.25V, PFO goes low - indicating degradation of the negative supply. Accuracy depends on resistor tolerance and PFI input bias current (≤25nA), so 1% resistors are recommended for ±5% overall trip-point error.

What is the maximum allowable VBATT voltage for MAX802LCPA+?

The maximum allowable VBATT voltage for MAX802LCPA+ is 4.80V, as specified in Table 2 of the datasheet. Exceeding this voltage 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. For lithium cells, this limit corresponds to fully charged LiMnO₂ (3.6V) or LiSOCl₂ (3.65V) cells - both well within safe margin. Do not connect 4.2V Li-ion cells without series resistance or regulation.