Analog Devices Inc./Maxim Integrated MAX793TCSE

Overview

MAX793TCSE from Maxim Integrated is a 3.3V microprocessor supervisory circuit with fixed reset threshold (3.00V–3.15V), backup-battery switchover, active-low/open-drain RESET output, and integrated chip-enable gating for CMOS RAM protection. It guarantees reset assertion down to VCC = 1V, supports battery voltages exceeding VCC (e.g., 3.6V Li), and delivers 7ns max CE IN-to-CE OUT propagation delay in normal operation - used in battery-backed embedded controllers requiring reliable power-fail detection and brownout immunity.

For engineers reviewing the MAX793TCSE datasheet, MAX793TCSE pinout, MAX793TCSE application, or MAX793TCSE equivalent, key selection criteria include its T-suffix reset threshold (3.00V–3.15V), 16-pin narrow SO package, guaranteed reset hold time (200ms), battery OK monitoring capability (MAX793 variant only), and compatibility with 3.0V/3.3V µP systems requiring low-line warning (LOWLINE) and watchdog-triggered reset support.

Technical Context

The MAX793TCSE implements a precision voltage comparator with 10mV typical hysteresis for reset assertion on VCC falling below 3.00V–3.15V, and includes an independent low-line comparator (LOWLINE) with 5–60mV adjustable hysteresis relative to VRST. Its internal p-channel MOSFET switch enables seamless VCC-to-BATT switchover when VCC drops below VSW (2.55V–2.95V depending on variant), with <15mV typical hysteresis to prevent oscillation.

It integrates a manual reset input (MR) with 70µA internal pullup, a 200ms reset timeout timer, and a transmission-gate-based CE IN/CE OUT path that disables during reset to protect RAM - with CE OUT driven high-impedance or pulled up to OUT, and propagation delay tested at 7ns (max) under 50Ω/50pF conditions.

Key Specifications

Pinout & Package

MAX793TCSE is housed in a 16-pin narrow SO (SOIC-16) package with 1.27mm pitch, JEDEC MS-012AC compliant, body size 10.3mm × 5.3mm × 1.75mm, moisture sensitivity level MSL-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX793SCSE, the MAX793TCSE provides tighter reset window alignment for ±5% 3.3V rails, while MAX795TCSE sacrifices monitoring features for footprint reduction - making MAX793TCSE optimal for full-featured, commercial-temp battery-backed controllers requiring both robustness and diagnostics.

Availability

MAX793TCSE is available at Aetrix Electronics and suitable for battery-powered embedded controllers, critical µP power monitoring systems, and intelligent remote terminals requiring stable component supply, long-lifecycle availability, and guaranteed commercial-temperature performance.

Supply support for MAX793TCSE 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and computing applications.

The MAX793 series belongs to Maxim's microprocessor supervisory product line, designed specifically to ensure reliable boot-up, brownout immunity, and data integrity in 3.0V/3.3V embedded systems with battery backup requirements.

FAQ

What is the reset threshold voltage range for MAX793TCSE?

The MAX793TCSE has a fixed reset threshold range of 3.00V to 3.15V (VCC falling), optimized for 3.3V ±5% power supplies. This ensures reset is asserted before the supply drops below 3.0V - the lower bound of system tolerance - and guarantees valid reset operation down to VCC = 1V. The 'T' suffix explicitly denotes this threshold variant.

Does MAX793TCSE support backup batteries with voltage higher than VCC?

Yes, MAX793TCSE supports backup-battery voltages exceeding VCC - such as standard 3.6V lithium cells in 3.3V systems. Its internal p-channel MOSFET switch enables seamless VCC-to-BATT switchover when VCC falls below the battery switch threshold (2.55V–2.95V), with built-in 15mV hysteresis to prevent oscillation during transition.

What is the function of the BATT OK output on MAX793TCSE?

The BATT OK output on MAX793TCSE is a dedicated battery health indicator that goes high when VBATT exceeds 2.0V (minimum), and low otherwise. It is continuously monitored during normal operation and disabled (logic low) when VCC falls below the battery switch threshold (VSW). This feature is exclusive to the MAX793 family and not present in MAX794/MAX795 variants.

How does the CE IN-to-CE OUT gating work in MAX793TCSE?

In MAX793TCSE, the CE IN-to-CE OUT path uses an internal transmission gate that passes signals during normal operation (reset deasserted) with ≤7ns propagation delay. When reset is asserted, the gate disables - blocking spurious CE transitions from corrupting CMOS RAM. If CE IN is low at reset assertion, CE OUT remains low for 10µs to complete the current write cycle before going high-impedance.

Can MAX793TCSE generate a reset pulse automatically on watchdog timeout?

Yes, MAX793TCSE can generate an automatic reset on watchdog timeout by connecting WDO to MR via a diode (anode to WDO, cathode to MR). When WDO goes low due to 1.6s WDI inactivity, it pulls MR low, initiating a 200ms reset pulse. The internal 70µA MR pullup ensures clean release, and the design avoids race conditions by holding CE OUT low for 10µs during the transition - ensuring safe RAM write completion.