Analog Devices Inc./Maxim Integrated MAX802TCSA+

Overview

MAX802TCSA+ from Maxim Integrated is a 3.3V microprocessor supervisory circuit with precision reset threshold (3.075V ±2%), 200ms reset timeout, watchdog timer (1.6s), battery-backup switchover, and power-fail detection. It monitors VCC supply integrity, asserts active-low RESET during brownout or watchdog timeout, and switches VOUT to VBATT when VCC falls below 2.40V-enabling reliable CMOS RAM retention in portable controllers and embedded systems.

For engineers reviewing the MAX802TCSA+ datasheet, MAX802TCSA+ pinout, MAX802TCSA+ application, or MAX802TCSA+ equivalent, this page delivers verified specifications including reset threshold tolerance (±2%), battery leakage current (≤1µA), VCC supply current (40µA typ), watchdog timeout accuracy (±40%), and SO-8 package compatibility-critical for low-power, battery-backed µP system design.

Technical Context

The MAX802TCSA+ integrates a precision voltage comparator with 2% reset threshold tolerance, a monostable reset timer with guaranteed 140–280ms assertion window, and a non-disableable watchdog timer triggered by WDI inactivity exceeding 1.6s. Its dual-supply architecture uses internal PMOS switches (3Ω VCC-to-VOUT, 140Ω VBATT-to-VOUT) to manage switchover at VSW = 2.40V with 25mV hysteresis.

It features an independent power-fail comparator (VPFT = 1.237V ±20mV) referenced to VCC, active-low PFO output, manual reset input with 70µA internal pull-up, and guaranteed RESET assertion down to VCC = 1.0V. All logic inputs (WDI, MR, PFI) operate across full VCC range (1.0–5.5V) with nanoscale leakage (±25nA).

Key Specifications

Pinout & Package

MAX802TCSA+ is housed in an 8-pin SOIC package (SO-8, 150mil width) with RoHS-compliant lead-free finish (+ suffix). Pin spacing conforms to JEDEC MS-012, thermal pad not required.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX802TESA+, MAX802TCSA+ offers lower temperature rating but identical electrical performance and footprint; compared with MAX706TESA+, it adds watchdog supervision, battery switchover, and power-fail detection-making it essential for safety-critical or battery-backed designs.

Availability

MAX802TCSA+ is available at Aetrix Electronics and suitable for battery-powered portable controllers, embedded industrial controllers, intelligent medical instruments, and critical µP power monitoring requiring stable component supply across production lifecycles.

Supply support for MAX802TCSA+ 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 power management, sensing, and interface applications in industrial, medical, and communications systems.

The MAX802 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust 3.0V/3.3V system power monitoring with integrated watchdog, battery switchover, and power-fail warning in space-constrained portable and embedded platforms.

FAQ

What is the guaranteed reset assertion voltage for MAX802TCSA+?

The MAX802TCSA+ guarantees active-low RESET assertion for VCC down to 1.0V, regardless of VBATT state. This ensures fail-safe reset behavior during deep brownout conditions where supply voltage collapses below typical logic thresholds-critical for preventing undefined µP states in safety-critical applications. The device maintains this guarantee across its full operating temperature range (0°C to +70°C).

Does MAX802TCSA+ support battery voltage higher than VCC?

Yes, MAX802TCSA+ explicitly supports VBATT exceeding VCC-such as a 3.6V lithium cell powering a 3.3V system. Its internal battery switchover circuit activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT through a 140Ω switch. This design allows safe, automatic backup power engagement without risk of reverse current or damage, even when VBATT > VCC during normal operation.

What is the watchdog timeout accuracy of MAX802TCSA+?

The MAX802TCSA+ watchdog timer has a nominal timeout of 1.6 seconds with ±40% variation over temperature and process. At TA = +25°C, typical timeout is 1.6s (1.12–2.24s min/max). Unlike some supervisory ICs, the watchdog function cannot be disabled-ensuring continuous firmware health monitoring. This fixed timeout eliminates external component dependencies while providing predictable fault recovery timing.

Can MAX802TCSA+ monitor a secondary power rail like +5V or -12V?

Yes, MAX802TCSA+ can monitor auxiliary rails using the PFI input with an external resistor divider. Its dedicated 1.237V reference and ±20mV threshold accuracy allow precise trip-point setting-for example, scaling a +5V rail to 1.237V at PFI triggers PFO low when +5V drops below 4.95V. The PFI input draws only ±25nA, minimizing divider loading error and enabling high-impedance monitoring of sensitive or isolated supplies.

Is MAX802TCSA+ pin-compatible with other MAX80x variants?

Yes, MAX802TCSA+ shares identical SO-8 pinout and function mapping with MAX802RCSA+, MAX802SCSA+, MAX804TCSA+, and MAX805TCSA+. All share VOUT/VCC/GND/PFI/PFO/WDI/RESET/VBATT assignments and electrical characteristics-only reset threshold (T=3.075V, S=2.925V, R=2.625V) and power-fail tolerance differ. This enables drop-in replacement across variants during design iteration or supply chain adjustments without PCB changes.