Analog Devices Inc./Maxim Integrated MAX6740XKZWD3

Overview

MAX6740XKZWD3 from Maxim Integrated is a triple-voltage microprocessor supervisor IC with two factory-trimmed reset thresholds (VTH1 = 2.313V, VTH2 = 1.665V) and one adjustable RSTIN input (488mV threshold), 150ms minimum reset timeout, open-drain RESET output, manual reset detect function, and 6µA supply current. It monitors I/O and core supplies in portable multivoltage systems requiring precise power sequencing and brownout protection.

For engineers reviewing the MAX6740XKZWD3 datasheet, MAX6740XKZWD3 pinout, MAX6740XKZWD3 application, or MAX6740XKZWD3 equivalent, key selection criteria include its SC70-5 package, dual fixed + single adjustable voltage monitoring capability, pushbutton-compatible manual reset detect, -40°C to +85°C operation, and compatibility with low-voltage core rails down to 0.9V.

Technical Context

The MAX6740XKZWD3 implements a triple-supply supervisory architecture with independent comparators for VCC1 (2.313V threshold), VCC2 (1.665V threshold), and RSTIN (488mV internal reference). Its reset assertion logic combines ORed fault detection across all three inputs and enforces a guaranteed 150ms minimum timeout after recovery.

It features an integrated 50kΩ internal pullup on the open-drain RESET pin enabling direct pushbutton interface without external components, and supports manual reset detect debouncing (37.5–75ms) to suppress switch bounce. The device operates from 1.2V to 5.5V supply range and maintains valid reset state while either VCC1 or VCC2 exceeds 1.2V.

Key Specifications

Pinout & Package

MAX6740XKZWD3 is housed in a 5-pin SC70-5 package (2.0mm × 2.1mm × 0.95mm height) with wettable flanks, lead-free compatible, and rated for -40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-supply supervisory applications.

Compared with MAX6743XKZWD3 and TPS3808G33DBVR, MAX6740XKZWD3 uniquely integrates triple monitoring, open-drain RESET with internal pullup, and manual reset detect in a 5-pin SC70-reducing board space and BOM count while supporting complex portable power architectures.

Availability

MAX6740XKZWD3 is available at Aetrix Electronics and suitable for portable medical sensors, notebook power management, industrial handheld terminals, and POS equipment requiring stable component supply with long-term manufacturability.

Supply support for MAX6740XKZWD3 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 portable applications.

The MAX6736–MAX6745 family was engineered specifically for multivoltage microprocessor systems needing compact, low-power, triple-rail supervision with flexible reset configuration and robust transient immunity.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6740XKZWD3?

The MAX6740XKZWD3 has a factory-trimmed VCC1 reset threshold of 2.313V, with tolerance of ±0.100V over the full -40°C to +85°C temperature range. This value is confirmed by the "ZW" suffix in the part number per Table 1 of the datasheet and is optimized for reliable supervision of 2.5V I/O rails under varying load and temperature conditions.

Does the MAX6740XKZWD3 support manual reset functionality, and how is it implemented?

Yes, the MAX6740XKZWD3 supports manual reset via its RESET pin, which features an internal 50kΩ pullup to VCC1. Pulling RESET low through a momentary switch to GND asserts reset; the device debounces the input for 37.5–75ms and holds RESET low for the full 150ms timeout period. No external components are required, distinguishing it from manual-reset-input-only variants like MAX6736.

What is the purpose of the RSTIN pin on the MAX6740XKZWD3, and what voltage range can it monitor?

The RSTIN pin on the MAX6740XKZWD3 provides an adjustable reset input with a precise 488mV internal reference. When used with an external resistor divider, it enables monitoring of any DC voltage down to 0.5V - for example, battery voltage or auxiliary supply rails. Input leakage is <10nA, minimizing impact on monitored circuits and preserving battery life in portable applications.

Can the MAX6740XKZWD3 be used in systems with negative supply voltages?

Yes, the MAX6740XKZWD3's RSTIN pin can monitor negative voltages using the circuit shown in Figure 4B of the datasheet: a resistor network referenced to VCC1 converts the negative rail into a positive voltage at RSTIN. When the negative supply is valid, RSTIN remains above 488mV; as it decays, RSTIN falls below threshold and triggers reset - enabling graceful shutdown of systems with dual-polarity supplies.

What package type and dimensions does the MAX6740XKZWD3 use, and is it RoHS-compliant?

The MAX6740XKZWD3 uses a 5-pin SC70-5 package measuring 2.0mm × 2.1mm × 0.95mm with wettable flanks. It is available in both leaded and lead-free versions; the standard "-T" suffix denotes lead-free packaging compliant with RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1.