Analog Devices Inc./Maxim Integrated MAX6797AKALTD7+T

Overview

The MAX6797AKALTD7+T from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (4.625V threshold), VCC2 (3.075V threshold), and an externally adjustable RSTIN input (626mV reference) with 26.25ms minimum reset timeout. It features push-pull active-low RST/RST1/RST2/PFO outputs, watchdog timer (35s startup / 1.12s normal), manual-reset input, and power-fail detection - deployed in telecom power systems requiring reliable brownout and fault recovery.

For engineers reviewing the MAX6797AKALTD7+T datasheet, MAX6797AKALTD7+T pinout, MAX6797AKALTD7+T application, or MAX6797AKALTD7+T equivalent, key selection criteria include guaranteed reset validity down to VCC1/VCC2 = 0.8V, ultra-low 14µA typical supply current at 3.6V, dual-mode watchdog timing, and factory-trimmed dual-threshold precision for multivoltage rail supervision.

Technical Context

The MAX6797AKALTD7+T implements independent voltage comparators for primary (VCC1) and secondary (VCC2) supplies plus a high-impedance RSTIN input referenced to a 626mV internal bandgap. Its reset logic asserts when any monitored voltage falls below its threshold and holds reset for a fixed 26.25ms (min) timeout after all thresholds are re-exceeded.

It integrates a dual-mode watchdog timer with 35s minimum startup period post-reset and 1.12s minimum normal timeout, plus MR input with 50kΩ internal pullup and PFI/PFO pair supporting power-fail warning without reset delay. All functions operate across –40°C to +125°C with supply voltage range 0.8V–5.5V per rail.

Key Specifications

Pinout & Package

MAX6797AKALTD7+T is housed in an 8-pin SOT23 package (3.0mm × 1.7mm × 1.3mm height), RoHS-compliant and tape-and-reel packaged (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6795AKALTD7+T and TPS3808G33DBVR, the MAX6797AKALTD7+T uniquely delivers triple-supply supervision with rail-specific push-pull outputs, integrated power-fail warning, and dual-mode watchdog - making it optimal for complex multivoltage systems where reliability and feature integration outweigh minimal cost premium.

Availability

MAX6797AKALTD7+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, automotive ADAS, and medical imaging applications requiring stable component supply, extended temperature operation, and certified RoHS compliance.

Supply support for MAX6797AKALTD7+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 and mixed-signal ICs for demanding industrial, automotive, and communications applications, emphasizing reliability, low power, and integration.

The MAX6715A–MAX6729A/MAX6797A family targets multivoltage embedded systems needing compact, accurate, and feature-rich power supervision - especially where space-constrained SOT23 packaging and guaranteed operation down to 0.8V are critical.

FAQ

What is the exact reset timeout period for MAX6797AKALTD7+T?

The MAX6797AKALTD7+T has a minimum reset timeout period of 26.25ms, corresponding to the D7 suffix in its part number. This value is guaranteed across –40°C to +125°C and ensures sufficient hold time for processor initialization before release. Typical timeout is 35ms, and maximum is 70ms under worst-case conditions.

Does MAX6797AKALTD7+T support monitoring a 1.2V core supply as the third voltage?

Yes, MAX6797AKALTD7+T supports monitoring a 1.2V core supply via its RSTIN pin using an external resistor divider. With a 626mV internal reference, a divider ratio of R1/R2 = 0.92 achieves a 1.2V trip point (VEXT_TH = 626mV × (R1 + R2)/R2). The high-impedance RSTIN input draws only ±100nA, enabling low-power divider design.

How does the watchdog timer behave after power-on reset in MAX6797AKALTD7+T?

After power-on reset, MAX6797AKALTD7+T enters a 35s minimum startup watchdog period, allowing full system boot. Once the first valid WDI edge occurs, it switches to 1.12s minimum normal timeout mode. If WDI remains static beyond either period, MAX6797AKALTD7+T asserts reset for 26.25ms. WDI left unconnected disables the watchdog.

Can MAX6797AKALTD7+T generate a power-fail interrupt without resetting the system?

Yes, MAX6797AKALTD7+T provides dedicated PFI/PFO functionality for this purpose. When PFI falls below 626.5mV (e.g., due to dropping battery voltage), PFO asserts low within 2µs - independently of reset logic. This signal can trigger MCU interrupts for orderly shutdown without issuing a system reset, preserving volatile state for diagnostics.

What is the supply voltage range over which MAX6797AKALTD7+T guarantees valid reset output?

MAX6797AKALTD7+T guarantees correct reset output logic state as long as either VCC1 or VCC2 remains above 0.8V. This specification ensures reliable brownout detection and reset assertion even during severe supply sag - critical for automotive and industrial applications where input voltage may dip transiently below nominal levels.