Analog Devices Inc./Maxim Integrated MAX6740XKVRD3+

Overview

The MAX6740XKVRD3+ from Maxim Integrated is a triple-voltage microprocessor supervisor IC with two factory-trimmed reset thresholds (VTH1 = 2.925V, VTH2 = 2.188V) and one adjustable RSTIN input (488mV threshold), open-drain RESET output, manual-reset-detect function, and 150ms minimum reset timeout. It monitors I/O and core supplies in portable multivoltage systems such as GPS equipment and PDAs.

For engineers reviewing the MAX6740XKVRD3+ datasheet, MAX6740XKVRD3+ pinout, MAX6740XKVRD3+ application, or MAX6740XKVRD3+ equivalent, key selection criteria include its SC70-5 package, dual fixed + single adjustable voltage monitoring capability, 6µA supply current, and integrated manual-reset-detect timing with internal 50kΩ pullup - critical for battery-powered system reliability and sequencing control.

Technical Context

The MAX6740XKVRD3+ implements independent comparators for VCC1 (2.925V threshold), VCC2 (2.188V threshold), and RSTIN (488mV reference), each feeding into a shared reset timer with 150ms minimum assertion period. Its open-drain RESET output includes an internal 50kΩ pullup to VCC1, enabling direct pushbutton interfacing without external components.

Reset assertion occurs when any monitored voltage falls below its threshold; deassertion requires all three inputs to exceed their thresholds simultaneously for the full timeout. The device operates across -40°C to +85°C and draws only 6µA total supply current at 3.3V/2.5V, making it suitable for ultra-low-power embedded supervision.

Key Specifications

Pinout & Package

MAX6740XKVRD3+ uses a 5-pin SC70-5 package with exposed pad (no thermal pad connection required). Pin 1 is RESET (open-drain active-low), Pin 2 is GND, Pin 3 is RSTIN (adjustable threshold input), Pin 4 is VCC2 (secondary supply monitor), and Pin 5 is VCC1 (primary supply monitor).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-voltage supervisor applications.

Compared with MAX6743XKVRD3+, the MAX6740XKVRD3+ offers integrated manual-reset-detect convenience; compared with TPS3808G33DBVR, it provides essential third-rail monitoring for complex multivoltage SoC designs - justifying its use where RSTIN functionality and robust reset assertion are mandatory.

Availability

MAX6740XKVRD3+ is available at Aetrix Electronics and suitable for GPS receivers, medical wearables, industrial PDAs, POS terminals, and battery-powered instrumentation requiring stable component supply with long-term lifecycle support.

Supply support for MAX6740XKVRD3+ 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, sensing, and connectivity in demanding industrial and portable applications.

The MAX6736–MAX6745 family delivers ultra-low-power, multi-rail supervision for space-constrained battery-operated systems - engineered specifically for reliable reset generation in GPS, medical, and handheld computing devices.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6740XKVRD3+?

The MAX6740XKVRD3+ has a factory-trimmed VCC1 reset threshold of 2.925V ±2.5% over -40°C to +85°C. This value is encoded in the "VR" suffix per Table 1 of the datasheet and applies specifically to the MAX6740 variant with D3 (150ms) timeout. The threshold is guaranteed monotonic and includes hysteresis of 0.5% of threshold voltage.

Does the MAX6740XKVRD3+ support manual reset functionality, and how is it implemented?

Yes, the MAX6740XKVRD3+ supports manual reset via its open-drain RESET output with integrated 50kΩ pullup to VCC1. Connecting a momentary switch between RESET and GND asserts reset; the internal debounce timer (tDEB = 37.5ms–75ms) eliminates contact bounce. No external components are needed - unlike the MAX6736/MAX6737 which require dedicated MR pin routing.

What is the purpose of the RSTIN pin on the MAX6740XKVRD3+, and what voltage range can it monitor?

The RSTIN pin on the MAX6740XKVRD3+ provides a third adjustable reset input with a precise 488mV internal reference. Using an external resistor divider, it can monitor supply voltages from 0.5V up to 5.0V. For example, a 100kΩ/10kΩ divider enables monitoring of a 5.4V rail at 488mV trip point. Input leakage is ≤10nA, allowing high-resistance dividers to minimize power loss.

Can the MAX6740XKVRD3+ be used in systems requiring power-supply sequencing, and if not, what alternative should be considered?

No, the MAX6740XKVRD3+ does not include a POK (power-ok) output for sequencing - that feature is exclusive to MAX6741/MAX6744 variants. For sequencing applications, consider MAX6741XKVRD3+, which adds an open-drain POK1 output that goes high after VCC1 exceeds 2.925V for 37.5ms, enabling controlled enablement of downstream regulators like VCC2.

What is the maximum supply voltage the MAX6740XKVRD3+ can tolerate on its VCC1 and VCC2 pins?

The MAX6740XKVRD3+ supports absolute maximum ratings of -0.3V to +6.0V on both VCC1 and VCC2 pins. However, functional operation is specified only from 1.0V to 5.5V for VCC1 and 0.9V to 3.3V for VCC2. Operating VCC2 above 3.3V may cause comparator inaccuracies or latch-up; sustained exposure to >6.0V risks permanent damage per Absolute Maximum Ratings.