Analog Devices Inc./Maxim Integrated MAX793SCSE+T

Overview

MAX793SCSE+T from Maxim Integrated is a 3.3V microprocessor supervisory circuit with fixed reset threshold (2.85V–3.00V), backup-battery switchover, active-low reset output, and integrated watchdog timer (1.6s timeout). It monitors VCC in battery-backed embedded controllers, asserts reset below threshold, gates CE signals with ≤7ns propagation delay, and supports low-line warning via LOWLINE output.

For engineers reviewing the MAX793SCSE+T datasheet, MAX793SCSE+T pinout, MAX793SCSE+T application, or MAX793SCSE+T equivalent, this page delivers verified specifications, validated pin functions, confirmed battery-switching behavior (VBATT > VCC supported), and real-world use cases in portable equipment and critical µP power monitoring.

Technical Context

The MAX793SCSE+T implements a precision voltage comparator with 10mV typical hysteresis for reset assertion/deassertion, a dedicated VCC-to-VBATT switchover circuit with 2.41V typical switch threshold (VCC falling), and an independent watchdog timer that clears on any WDI transition. Its CE gating uses a series transmission gate with 46Ω on-resistance and guaranteed 7ns max propagation delay.

It integrates a low-line comparator (VLL = 2.925V rising) with 15mV hysteresis, BATT OK monitoring (2.00V min threshold), and manual reset input with 70µA internal pullup. All outputs-including RESET (open-drain), RESET (push-pull), WDO, PFO, and LOWLINE-are fully specified across 0°C to +70°C.

Key Specifications

Pinout & Package

MAX793SCSE+T is housed in a 16-pin narrow SO package (SOIC-16, 3.9mm width), RoHS-compliant and lead-free (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX793TCSE+T, the MAX793SCSE+T provides earlier reset assertion for wider 3.3V ±10% supplies, while TPS3808G33DBVR offers footprint reduction at the cost of losing battery management and memory protection features essential in mission-critical embedded systems.

Availability

MAX793SCSE+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent controllers, critical µP power monitoring, and portable equipment requiring stable component supply across industrial temperature ranges.

Supply support for MAX793SCSE+T 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, mixed-signal, and power-management ICs for industrial, communications, computing, and consumer applications.

The MAX793 family delivers integrated µP supervision with battery switchover, watchdog, and CE gating-designed specifically for reliable operation in 3.0V/3.3V battery-backed embedded systems where data integrity and power-fail response are critical.

FAQ

What is the exact reset threshold voltage range for MAX793SCSE+T?

The MAX793SCSE+T has a fixed reset threshold range of 2.85V to 3.00V (VCC falling), corresponding to the 'S' suffix. This is verified in the Electrical Characteristics table under VRST parameter, with typical value 2.925V and guaranteed min/max across temperature. The threshold applies to both reset assertion and deassertion with 10mV hysteresis to prevent oscillation during brownout recovery. MAX793SCSE+T does not support adjustable reset thresholds like the MAX794.

Does MAX793SCSE+T support backup batteries with voltage higher than VCC?

Yes, MAX793SCSE+T explicitly supports VBATT > VCC, enabling use of standard 3.6V lithium batteries with 3.3V main supplies. The datasheet confirms VBATT can reach 6.0V absolute maximum, and the battery switchover circuit activates when VCC falls below 2.41V (typical), connecting OUT to BATT regardless of VBATT exceeding VCC. This behavior is guaranteed in the Absolute Maximum Ratings and Electrical Characteristics sections for MAX793SCSE+T.

How does the CE gating function work on MAX793SCSE+T, and what is its propagation delay?

The MAX793SCSE+T uses an internal transmission gate between CE IN (Pin 11) and CE OUT (Pin 12) that enables only when reset is inactive. During reset assertion, CE OUT is forced low for up to 10µs if CE IN was low, ensuring memory write completion. The propagation delay is guaranteed ≤7ns max under test conditions (50Ω source, 50pF load), verified in the Electrical Characteristics table. This delay preserves timing margins for high-speed µP–RAM interfaces.

Is the watchdog timer in MAX793SCSE+T configurable or disableable?

No, the watchdog timer in MAX793SCSE+T is fixed at 1.6s timeout and cannot be disabled. The datasheet states "unlike the 5V MAX690 family, the watchdog function cannot be disabled." It clears on any WDI edge (low-to-high or high-to-low) and asserts WDO low if no transition occurs within 1.6s. This behavior is confirmed in the Detailed Description section and applies identically to MAX793SCSE+T as part of the MAX793 family.

What is the purpose and activation method of the battery freshness seal in MAX793SCSE+T?

The battery freshness seal in MAX793SCSE+T disconnects the backup battery from internal circuitry until first power-up, minimizing shelf-life degradation. It is activated by grounding PFO while bringing VCC above the reset threshold, holding it until reset deasserts (200ms), then cycling VCC down. Once enabled, the seal remains active until VCC exceeds VRST again. This process is documented in the Battery Freshness Seal section and confirmed for MAX793SCSE+T via its inclusion in the MAX793/MAX794 feature set.