Analog Devices Inc./Maxim Integrated MAX6734KAYHD3

Overview

MAX6734KAYHD3 from Maxim Integrated is a triple-voltage microprocessor supervisor IC with independent watchdog output, monitoring two fixed supply rails (VCC1 = +2.925V, VCC2 = +2.188V) and one adjustable rail via RSTIN (626.5mV threshold), featuring 210ms reset timeout and open-drain RST/WDO outputs in an 8-pin SOT23 package. It ensures system reliability in multivoltage embedded controllers during power-up, brownout, or software lockup.

For engineers reviewing the MAX6734KAYHD3 datasheet, MAX6734KAYHD3 pinout, MAX6734KAYHD3 application, or MAX6734KAYHD3 equivalent, key selection criteria include its dual fixed-threshold supervision (+2.925V / +2.188V), adjustable third-rail monitoring down to +0.63V, 210ms reset timeout, watchdog startup delay (35s min), and guaranteed reset validity down to VCC = +0.8V.

Technical Context

The MAX6734KAYHD3 implements three independent voltage monitors: a primary comparator for VCC1 at +2.925V (±12.5mV), a secondary for VCC2 at +2.188V (±12.5mV), and a high-impedance adjustable input (RSTIN) referenced to a 626.5mV internal bandgap. All comparators feed into a shared reset timer with 210ms nominal timeout (140–280ms range).

Its watchdog circuit operates in dual-mode: 35s minimum startup delay after reset, then transitions to 1.12s minimum normal timeout upon first WDI edge detection. The active-low open-drain RST and WDO outputs require external pullups and assert when any monitored voltage falls below threshold, MR is pulled low, or WDI stalls - ensuring fail-safe µP supervision without external components.

Key Specifications

Pinout & Package

MAX6734KAYHD3 is housed in an 8-pin SOT23-8 package (3.00mm × 2.80mm × 1.30mm body, 0.65mm pitch), optimized for space-constrained PCB layouts while maintaining thermal performance up to +85°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6734KAYHD3, MAX6734KASVD3-T offers lower VCC2 threshold for sub-1.8V systems, while MAX6732UTSYD3-T reduces size and cost by omitting RSTIN - making it suitable only when triple-rail supervision is not required.

Availability

MAX6734KAYHD3 is available at Aetrix Electronics and suitable for industrial PLC controllers, telecom line cards, medical patient monitors, and network router SoC modules requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6734KAYHD3 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 delivers integrated triple-voltage supervision and independent watchdog functionality specifically for space- and power-constrained µP-based systems requiring high reliability under brownout and software fault conditions.

FAQ

What are the exact factory-set reset thresholds for MAX6734KAYHD3?

The MAX6734KAYHD3 has VCC1 threshold of +2.925V (±12.5mV) and VCC2 threshold of +2.188V (±12.5mV), per the "YH" suffix in its ordering code. Its RSTIN input uses a fixed 626.5mV internal reference for adjustable third-rail monitoring. These values are laser-trimmed at wafer test and guaranteed over -40°C to +85°C.

Does MAX6734KAYHD3 support push-pull or open-drain reset output?

MAX6734KAYHD3 provides an open-drain RST output, as confirmed by its MAX6734 designation (per Selector Guide). It requires an external pullup resistor to generate a valid logic-high level. This configuration avoids contention with bidirectional µP reset pins and simplifies interfacing in mixed-voltage systems.

What is the reset timeout period for MAX6734KAYHD3 and how is it set?

The MAX6734KAYHD3 features a 210ms nominal reset timeout period (range: 140–280ms), indicated by the "D3" suffix. This timeout is factory-programmed and non-adjustable. It defines the minimum duration RST remains asserted after all monitored voltages exceed their thresholds or after MR release.

Can MAX6734KAYHD3 monitor a +1.2V supply as the third rail?

Yes - the MAX6734KAYHD3 can monitor a +1.2V supply using its RSTIN pin. With a 626.5mV internal reference, a simple resistor divider (e.g., R1 = 1.0MΩ, R2 = 1.1MΩ) scales +1.2V to ~626mV at RSTIN. Input leakage is only ±25nA, minimizing divider current and power loss.

How does the watchdog timer behave during power-up of MAX6734KAYHD3?

Upon power-up or reset, the MAX6734KAYHD3 watchdog enters a 35s minimum startup delay mode. During this period, WDO remains deasserted regardless of WDI state. After the first valid WDI edge or expiration of 35s, it switches to 1.12s minimum normal timeout mode - ensuring safe boot before watchdog enforcement begins.