Analog Devices Inc./Maxim Integrated MAX6734KALTD3

Overview

MAX6734KALTD3 from Maxim Integrated is a triple-voltage microprocessor supervisor IC with independent watchdog output, monitoring +4.625V (VCC1), +3.075V (VCC2), and an adjustable input down to +0.63V (RSTIN). It features open-drain RST and WDO outputs, 140–280ms reset timeout, manual reset input, and operates over –40°C to +85°C in SOT23-8. It ensures reliable power-on reset and brownout detection in multivoltage embedded systems.

For engineers reviewing the MAX6734KALTD3 datasheet, MAX6734KALTD3 pinout, MAX6734KALTD3 application, or MAX6734KALTD3 equivalent, key selection criteria include dual fixed-threshold supervision (+4.625V/+3.075V), third adjustable threshold via RSTIN, 140–280ms reset timeout, open-drain reset/watchdog outputs, and manual reset capability in an 8-pin SOT23 package.

Technical Context

The MAX6734KALTD3 integrates three independent voltage monitors: two factory-set comparators for VCC1 and VCC2 (here +4.625V and +3.075V), plus a high-impedance adjustable comparator on RSTIN referenced to a precise 626mV internal bandgap. Its dual-mode watchdog timer provides a 35s minimum startup delay after reset and a 1.12s minimum normal-mode timeout.

Reset assertion is guaranteed down to VCC1 or VCC2 = +0.8V, and the device maintains valid logic levels across its full operating range. The open-drain RST and WDO outputs require external pullups and support interfacing with bidirectional µP reset pins without contention when used with appropriate series resistance.

Key Specifications

Pinout & Package

SOT23-8 package: 3.0mm × 2.8mm body, 0.65mm lead pitch, 0.9mm max height, JEDEC MO-178 compliant. RoHS-compliant, available in leaded and lead-free variants.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6735KALTD3-T, MAX6734KALTD3 offers open-drain flexibility for shared reset buses but requires pullups; compared with TPS3808G33DBVR, it delivers full triple-supply supervision and manual reset in one device-reducing component count by ≥2 in multivoltage designs.

Availability

MAX6734KALTD3 is available at Aetrix Electronics and suitable for telecom line cards, industrial PLC controllers, network router power management, and battery-powered medical sensors requiring stable component supply and long-term industrial lifecycle support.

Supply support for MAX6734KALTD3 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 industrial, automotive, communications, and computing markets.

The MAX6730–MAX6735 family was engineered to replace discrete reset circuits in multivoltage µP systems, delivering integrated triple-supply monitoring, manual reset, and dual-mode watchdog functionality in ultra-small SOT23 packages.

FAQ

What are the exact factory-set reset thresholds for MAX6734KALTD3?

The MAX6734KALTD3 has a VCC1 reset threshold of +4.625V (±125mV) and a VCC2 reset threshold of +3.075V (±75mV), per the "LT" suffix in its part number. These values are laser-trimmed at wafer test and guaranteed over temperature. The RSTIN input uses a fixed 626mV internal reference, enabling monitoring of third supplies down to +0.63V using an external resistor divider. All thresholds are specified in the MAX6734KALTD3 datasheet Table 1 and Electrical Characteristics section.

Does MAX6734KALTD3 support manual reset, and how is it implemented?

Yes, MAX6734KALTD3 includes an active-low manual reset input (MR) on Pin 4. It features an internal 50kΩ pullup resistor to VCC1, allowing MR to be left unconnected if unused. Driving MR low forces immediate RST assertion for the full reset timeout period (140–280ms), clearing the watchdog timer and deasserting WDO. MR accepts standard TTL/CMOS logic levels and supports momentary switch interfaces without external debounce circuitry, making it ideal for field-service reset buttons in industrial equipment.

What is the function of the RSTIN pin on MAX6734KALTD3, and how do I use it?

The RSTIN pin (Pin 7) on MAX6734KALTD3 is a high-impedance comparator input referenced to an internal 626mV bandgap voltage. To monitor a third supply voltage higher than 626mV, connect a resistive divider between that supply and GND, with the midpoint feeding RSTIN. For example, to monitor +5V, use R1 = 6.8kΩ and R2 = 1.0kΩ to scale it to ~641mV. The MAX6734KALTD3 asserts RST low when the voltage at RSTIN falls below 626mV, providing precise undervoltage detection for auxiliary rails or battery inputs.

How does the watchdog timer operate in MAX6734KALTD3, and what are its timing modes?

The MAX6734KALTD3 watchdog timer operates in two distinct modes: a 35s minimum startup delay after any reset event (power-up, brownout, or MR activation), followed by a 1.12s minimum normal timeout during steady-state operation. A rising or falling edge on WDI (Pin 5) clears the timer; failure to provide such an edge within the active timeout period causes WDO (Pin 8) to assert low. This dual-mode architecture prevents false timeouts during boot while ensuring rapid detection of runtime firmware hangs-critical for safety-critical embedded systems using MAX6734KALTD3.

What package type and footprint does MAX6734KALTD3 use, and are there layout considerations?

MAX6734KALTD3 uses an 8-pin SOT23-8 package (JEDEC MO-178 BA variant) measuring 3.0mm × 2.8mm with 0.65mm lead pitch. Key layout considerations include placing a 0.1µF ceramic bypass capacitor between VCC1 and GND as close as possible to Pins 6 and 2, routing MR with a 0.1µF capacitor to GND for noise immunity in long-cable applications, and using 4.7kΩ–10kΩ pullup resistors on RST and WDO (Pins 1 and 8) for open-drain operation. Thermal relief pads are recommended for soldering reliability.