Analog Devices Inc./Maxim Integrated MAX6734KASDD3

Overview

The MAX6734KASDD3 from Maxim Integrated is a triple-voltage microprocessor supervisor IC with independent watchdog output, monitoring +3.075V (VCC1), +2.188V (VCC2), and an adjustable input down to +0.626V (RSTIN), featuring 210ms reset timeout, open-drain RST/WDO outputs, and manual reset input - used in multivoltage telecom and industrial systems for reliable power-on and brownout detection.

For engineers reviewing the MAX6734KASDD3 datasheet, MAX6734KASDD3 pinout, MAX6734KASDD3 application, or MAX6734KASDD3 equivalent, key selection criteria include dual fixed-threshold supervision (+3.075V/+2.188V), adjustable third-channel threshold (626mV), 210ms reset timeout, -40°C to +85°C operation, and SOT23-8 open-drain output compatibility with µP reset I/O interfaces.

Technical Context

The MAX6734KASDD3 implements three independent voltage monitors: a primary comparator for VCC1 at +3.075V (suffix "AS"), a secondary comparator for VCC2 at +2.188V (suffix "SD"), and a high-impedance adjustable comparator on RSTIN referenced to 626mV. All thresholds feature ±0.5% hysteresis and 20ppm/°C tempco.

Its watchdog architecture 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 assert when any monitored supply falls below threshold, RSTIN drops below 626mV, or MR is pulled low - with guaranteed reset validity down to VCC1/VCC2 = +0.8V.

Key Specifications

Pinout & Package

MAX6734KASDD3 is housed in an 8-pin SOT23-8 package (JEDEC MO-178 BA), measuring 3.00mm × 1.75mm × 1.30mm, with gull-wing leads and pin 1 marked by a dot. The package supports lead-free assembly (RoHS-compliant) and operates up to +150°C junction temperature.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6734KASDD3, MAX6735KASDD3 offers push-pull outputs for direct drive but loses wired-OR flexibility, while TPS3808G33DBVR reduces functionality to basic +3.3V supervision - making MAX6734KASDD3 optimal for multivoltage systems requiring configurable third-rail monitoring and open-drain interoperability.

Availability

MAX6734KASDD3 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and battery-operated edge devices requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6734KASDD3 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 communications applications.

The MAX6730–MAX6735 family delivers integrated triple-voltage supervision with independent watchdog functionality, targeting space-constrained multirail systems where reliability, low power, and flexible reset timing are critical.

FAQ

What are the exact factory-set reset thresholds for MAX6734KASDD3?

The MAX6734KASDD3 has VCC1 threshold = +3.075V (suffix "AS") and VCC2 threshold = +2.188V (suffix "SD"), both with ±0.5% hysteresis and 20ppm/°C tempco. These values are laser-trimmed at wafer test and guaranteed over -40°C to +85°C. The RSTIN input uses a fixed 626mV internal reference, enabling precise third-rail monitoring via external resistive dividers - a key differentiator of the MAX6734KASDD3 within its family.

Does MAX6734KASDD3 support manual reset, and how is it implemented?

Yes, MAX6734KASDD3 includes an active-low manual reset input (MR) on pin 7, internally pulled up to VCC1 with 50kΩ. Driving MR low forces immediate RST assertion for the full reset timeout period (140–280ms). It accepts TTL/CMOS logic levels, rejects <100ns glitches, and requires no external debounce - simplifying front-panel reset integration. This MR function is shared with MAX6730/MAX6731/MAX6735 but omitted in MAX6732/MAX6733, confirming MAX6734KASDD3's role in user-serviceable systems.

What is the watchdog timeout behavior of MAX6734KASDD3 during power-up?

MAX6734KASDD3 features a dual-mode watchdog: after any reset event (power-up, brownout, or MR), it enters a 35s minimum startup delay (tWD-L) to allow full system initialization. Only after this period - or upon detection of the first valid WDI edge - does it switch to the 1.12s minimum normal timeout (tWD-S). This prevents spurious resets during boot while ensuring rapid fault response thereafter - a behavior confirmed in the MAX6734KASDD3 functional diagram and timing figures.

Can MAX6734KASDD3 monitor a +5V supply, and if so, how?

MAX6734KASDD3 cannot directly monitor +5V on VCC1 or VCC2, as its factory-set thresholds max out at +4.625V (LT) and +3.075V (AS) respectively. However, it can monitor +5V indirectly via the RSTIN pin: using a resistive divider (e.g., R1 = 100kΩ, R2 = 160kΩ) to scale +5V down to 626mV, satisfying VRSTIN = 626mV × (R1 + R2)/R2. This method is explicitly validated in the MAX6734KASDD3 datasheet Figure 2 and enables precise +5V supervision without external comparators.

What package and footprint does MAX6734KASDD3 use, and are there layout considerations?

MAX6734KASDD3 uses an 8-pin SOT23-8 package (JEDEC MO-178 BA) with 0.65mm pitch, 3.00mm × 1.75mm body, and gull-wing leads. Critical layout practices include placing a 0.1µF ceramic capacitor between VCC1 and GND close to the device, routing MR with a 0.1µF cap to GND for noise immunity, and using short, direct traces for RSTIN to minimize leakage-induced errors - all recommended in the MAX6734KASDD3 datasheet Applications Information section.