Analog Devices Inc./Maxim Integrated MAX6740XKSDD3

Overview

The MAX6740XKSDD3 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), 150ms minimum reset timeout, open-drain RESET output, manual reset detect function, and SC70-5 package. It monitors I/O and core supplies in portable multivoltage systems to ensure reliable µP initialization.

For engineers reviewing the MAX6740XKSDD3 datasheet, MAX6740XKSDD3 pinout, MAX6740XKSDD3 application, or MAX6740XKSDD3 equivalent, key selection criteria include its triple-supply monitoring capability, 6µA supply current, 0.488V adjustable threshold support, -40°C to +85°C operation, and compatibility with battery-powered embedded controllers requiring precise power sequencing and glitch-immune reset assertion.

Technical Context

The MAX6740XKSDD3 implements dual fixed-threshold comparators for VCC1 and VCC2 plus a dedicated 0.488V reference comparator for the RSTIN input, all feeding into a shared reset timeout timer. Its internal 50kΩ pullup on the open-drain RESET pin enables manual reset detection without external components.

Reset assertion occurs when any monitored voltage falls below its threshold; the 150ms timeout begins only after all voltages exceed their thresholds. The device guarantees valid RESET state down to VCC1 = 1.2V and supports transient immunity up to 100µs for 100mV overdrive, per typical operating characteristics.

Key Specifications

Pinout & Package

MAX6740XKSDD3 uses a 5-pin SC70 package with exposed pad (not electrically connected). 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 MAX6743XKSDD3 and TPS3808G33DBVR, the MAX6740XKSDD3 uniquely delivers triple-supply monitoring with integrated manual reset detect in SC70-5, enabling compact, low-power designs that require supervision of I/O, core, and auxiliary rails - a capability neither alternative provides.

Availability

MAX6740XKSDD3 is available at Aetrix Electronics and suitable for portable medical sensors, industrial handheld terminals, smart energy meters, and wearable health monitors requiring stable component supply across extended production lifecycles.

Supply support for MAX6740XKSDD3 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 management, sensing, and connectivity in demanding industrial and portable applications.

The MAX6736–MAX6745 family was engineered specifically for multivoltage microprocessor systems needing ultra-low-power, high-accuracy reset supervision with flexible threshold configuration - targeting battery-operated and space-constrained embedded platforms.

FAQ

What is the exact reset timeout period for MAX6740XKSDD3?

The MAX6740XKSDD3 has a minimum reset timeout period of 150ms, as indicated by the "D3" suffix in its part number. This value is guaranteed over the full -40°C to +85°C operating temperature range and begins only after all monitored supplies (VCC1, VCC2, RSTIN) exceed their respective thresholds. Typical timeout is 225ms, with a maximum of 300ms per electrical characteristics table.

Does MAX6740XKSDD3 support manual reset functionality?

Yes, MAX6740XKSDD3 supports manual reset detection via its open-drain RESET pin, which includes an internal 50kΩ pullup resistor to VCC1. When the RESET pin is externally pulled low (e.g., by a pushbutton to GND), the device detects this as a manual reset event, asserts RESET for the full 150ms timeout, and debounces the input for 37.5ms to reject switch bounce - no external components required.

What are the factory-trimmed voltage thresholds for MAX6740XKSDD3?

The MAX6740XKSDD3 has two factory-trimmed thresholds: VTH1 = 2.925V for VCC1 (I/O supply) and VTH2 = 2.188V for VCC2 (core supply), both with ±75mV tolerance over -40°C to +85°C. These values correspond to the "KS" suffix per Table 1. The RSTIN input uses a fixed 0.488V internal reference, enabling monitoring of voltages as low as 0.5V via external resistor divider.

Can MAX6740XKSDD3 monitor a negative supply voltage?

Yes, MAX6740XKSDD3 can monitor a negative supply using its RSTIN input with an external resistor network configured as shown in Figure 4B of the datasheet. In this configuration, the negative rail is referenced to GND through R1/R2, and RSTIN asserts reset when the negative voltage drops below the trip point derived from the 0.488V internal reference. Accuracy depends on resistor tolerance and PFI input leakage (<10nA).

What is the supply current consumption of MAX6740XKSDD3 at 25°C?

At TA = +25°C, the MAX6740XKSDD3 consumes 6µA typical total supply current (ICC1 + ICC2), with a maximum of 10µA over temperature. This ultra-low quiescent current is measured with VCC1 = 3.3V, VCC2 = 2.5V, and no reset asserted - making it ideal for battery-powered applications where multi-year operation is required without recharging.