Analog Devices Inc./Maxim Integrated MAX793TCSE+T

Overview

MAX793TCSE+T from Maxim Integrated is a 3.3V microprocessor supervisory circuit with fixed 3.00V–3.15V reset threshold, backup-battery switchover (VBATT > VCC), active-low/open-drain RESET output, and integrated watchdog timer (1.6s timeout). It monitors critical power rails in battery-backed embedded controllers and provides chip-enable gating with ≤7ns propagation delay to protect CMOS RAM during undervoltage events.

For engineers reviewing the MAX793TCSE+T datasheet, MAX793TCSE+T pinout, MAX793TCSE+T application, or MAX793TCSE+T equivalent, key selection criteria include guaranteed reset assertion down to VCC = 1V, battery-switch threshold at 2.55V (VCC falling), low-line warning output (LOWLINE), and BATT OK status monitoring - all in a 16-pin narrow SO package rated for 0°C to +70°C operation.

Technical Context

The MAX793TCSE+T implements a precision voltage comparator with 10mV typical hysteresis to prevent oscillation during VCC transitions near the 3.085V nominal reset threshold. Its internal p-channel MOSFET switch enables seamless switchover from VCC to VBATT when VCC drops below 2.55V (VCC falling) or rises above VRST (2.55V–3.15V range) during recovery.

It integrates a dedicated watchdog timer that clears on any WDI transition and asserts WDO low after 1.6s of inactivity; WDO can be diode-OR'd to MR to generate automatic system resets. The CE IN-to-CE OUT transmission gate operates with ≤7ns propagation delay and disables during reset to block spurious writes to CMOS RAM.

Key Specifications

Pinout & Package

MAX793TCSE+T is housed in a 16-pin narrow SO (SOIC-16) package with standard 1.27mm pitch, JEDEC MS-012AC compliant, RoHS-compliant lead-free finish (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX793TCSA+, the MAX793TCSE+T delivers superior thermal dissipation and smaller PCB footprint; compared with TPS3808G33DBVR, it adds essential battery switchover, watchdog, and memory protection features absent in the TI device - making it irreplaceable in systems requiring robust, multi-function power supervision.

Availability

MAX793TCSE+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent controllers requiring stable component supply across commercial temperature ranges.

Supply support for MAX793TCSE+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 demanding industrial, automotive, and communications applications.

The MAX793 series belongs to Maxim's microprocessor supervisory product line, engineered specifically to ensure reliable µP startup, brownout recovery, and battery-backed memory integrity in 3.0V/3.3V embedded systems.

FAQ

What is the exact reset threshold voltage range for MAX793TCSE+T?

The MAX793TCSE+T has a fixed reset threshold range of 3.00V to 3.15V (VCC falling), with a nominal value of 3.085V at +25°C. This range is guaranteed across the full 0°C to +70°C operating temperature range and ensures reset assertion before a 3.3V supply degrades beyond 10% tolerance. The 'T' suffix explicitly denotes this threshold variant.

Does MAX793TCSE+T support backup battery voltages higher than VCC?

Yes, MAX793TCSE+T supports VBATT exceeding VCC - up to 3.6V - enabling use of standard lithium coin cells in 3.0V/3.3V systems. Its internal p-channel MOSFET switch automatically connects OUT to BATT when VCC falls below 2.55V (VCC falling), and reconnects to VCC when VCC rises above the reset threshold, with built-in 15mV hysteresis to prevent oscillation.

How does the watchdog timer in MAX793TCSE+T operate?

The MAX793TCSE+T watchdog timer has a fixed 1.6s timeout period. It clears on any rising or falling edge at WDI and asserts WDO low if no transition occurs within that window. WDO remains low until the next WDI edge, and can be directly connected to MR to generate an automatic 200ms reset pulse - providing autonomous recovery from µP lockups without firmware intervention.

What is the purpose of the LOWLINE output on MAX793TCSE+T?

The LOWLINE output on MAX793TCSE+T provides early power-fail warning by asserting low when VCC falls to approximately 30mV below the reset threshold (e.g., ~3.00V for the 'T' variant). This allows the µP to trigger a non-maskable interrupt (NMI) and execute graceful shutdown routines - such as saving volatile data to EEPROM - before RESET is asserted and system execution halts.

Can MAX793TCSE+T protect CMOS RAM during power transitions?

Yes, MAX793TCSE+T protects CMOS RAM via its integrated CE gating function. The CE IN-to-CE OUT transmission gate passes signals during normal operation but disables automatically during RESET assertion, blocking spurious writes. With ≤7ns propagation delay and 10µs hold time when CE IN is low at reset onset, it ensures write-cycle completion and prevents data corruption during undervoltage events.