Analog Devices Inc./Maxim Integrated MAX6740XKLTD3

Overview

The MAX6740XKLTD3 from Maxim Integrated is a triple-voltage microprocessor supervisor IC with two factory-trimmed reset thresholds (VTH1 = 4.625V, VTH2 = 3.075V) and one adjustable RSTIN input (488mV reference), 150ms minimum reset timeout, open-drain RESET output, manual reset detect function, and 6µA supply current. It monitors primary I/O (VCC1), secondary core (VCC2), and auxiliary (RSTIN) supplies in portable multivoltage systems.

For engineers reviewing the MAX6740XKLTD3 datasheet, MAX6740XKLTD3 pinout, MAX6740XKLTD3 application, or MAX6740XKLTD3 equivalent, key selection criteria include its triple-supply monitoring capability, SC70-5 package footprint, -40°C to +85°C operation, low-power supervision for battery-powered devices, and compatibility with manual reset pushbutton interfaces without external debouncing circuitry.

Technical Context

The MAX6740XKLTD3 implements a dual-fixed + single-adjustable voltage monitoring architecture with independent comparators for VCC1, VCC2, and RSTIN, each referenced to precision internal bandgap references. Its reset assertion logic combines ORed fault detection across all three inputs and enforces a guaranteed 150ms minimum deassertion hold time after all voltages recover.

It features an integrated 50kΩ internal pullup on the open-drain RESET pin enabling manual reset detect functionality-allowing direct connection to a momentary switch without external components-and uses BiCMOS process technology to achieve 6µA total quiescent current while maintaining valid reset state down to VCC1 ≥ 1.2V.

Key Specifications

Pinout & Package

MAX6740XKLTD3 is housed in a 5-pin SC70-5 package (1.6mm × 1.6mm × 0.9mm height) with gull-wing leads, optimized for high-density portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6743XKLTD3, the MAX6740XKLTD3 provides manual reset detect capability out-of-the-box, reducing design effort; versus TPS3808G33DBVR, it adds essential third-rail monitoring for complex SoC power domains but consumes slightly more current.

Availability

MAX6740XKLTD3 is available at Aetrix Electronics and suitable for portable/battery-powered equipment, multivoltage systems, and notebook computers requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MAX6740XKLTD3 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, computing, and consumer applications.

The MAX6736–MAX6745 product line was designed specifically for space-constrained, low-power multivoltage systems-delivering integrated triple-supply supervision in sub-2mm² SC70 packages with µA-level quiescent current.

FAQ

What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6740XKLTD3?

The MAX6740XKLTD3 has factory-trimmed reset thresholds of 4.625V for VCC1 (±75mV over -40°C to +85°C) and 3.075V for VCC2 (±50mV over temperature). These values are encoded in the "LT" suffix per Maxim's ordering guide and are verified across production lots-not typical or nominal values.

Does the MAX6740XKLTD3 support manual reset functionality, and how is it implemented?

Yes, the MAX6740XKLTD3 supports manual reset via its open-drain RESET pin, which includes an internal 50kΩ pullup resistor to VCC1. When a momentary switch connects RESET to GND, the device detects the low state, asserts RESET fully, and holds it for the 150ms timeout period after release-eliminating need for external debounce components.

Can the MAX6740XKLTD3 monitor a 1.2V supply rail, and if so, how?

Yes, the MAX6740XKLTD3 can monitor a 1.2V rail using its RSTIN pin. By connecting a resistor divider between VCC1 and GND-with RSTIN tied to the midpoint-the internal 0.488V reference sets the trip point. For 1.2V, use R1 = 1.5MΩ and R2 = 1MΩ to yield V_{EXT_TH} = 0.488V × (2.5MΩ / 1MΩ) = 1.22V, matching the target threshold.

What is the supply current consumption of the MAX6740XKLTD3 under typical operating conditions?

The MAX6740XKLTD3 draws a maximum of 6µA total supply current (ICC1 + ICC2) across -40°C to +85°C when both VCC1 and VCC2 are above their thresholds and RESET is not asserted. This value is specified in the Electrical Characteristics table and confirmed in Typical Operating Characteristics plots.

Is the MAX6740XKLTD3 pin-compatible with other devices in the MAX6736–MAX6745 family?

No-pin compatibility within the MAX6736–MAX6745 family is variant-specific. The MAX6740XKLTD3 uses Pin 3 for VCC2 and Pin 4 for RSTIN, whereas MAX6741/MAX6744 place POK1 on Pin 4 and MAX6742/MAX6745 place PFI/PFO there. Always verify pin configuration from the official SC70 top-view diagram for each specific part number.