Analog Devices Inc./Maxim Integrated MAX6733AUTSHD3+

Overview

MAX6733AUTSHD3+ from Maxim Integrated is a dual-voltage microprocessor supervisor IC with push-pull reset output, active-low watchdog output, and factory-set reset thresholds of +2.925V (VCC1) and +1.313V (VCC2). It features a 140ms–280ms reset timeout period (D3), 1.12s normal watchdog timeout, and operates across –40°C to +125°C. Used in multivoltage embedded systems to ensure reliable power-on and brownout reset sequencing for processors and memory.

For engineers reviewing the MAX6733AUTSHD3+ datasheet, MAX6733AUTSHD3+ pinout, MAX6733AUTSHD3+ application, or MAX6733AUTSHD3+ equivalent, key selection criteria include dual-supply monitoring accuracy, push-pull RST drive capability, independent watchdog timing architecture, and SOT23-6 package compatibility with space-constrained industrial and telecom designs.

Technical Context

The MAX6733AUTSHD3+ monitors two fixed supply rails-VCC1 at +2.925V and VCC2 at +1.313V-with guaranteed reset assertion down to VCC ≥ +0.8V. Its internal comparators feature 20ppm/°C tempco and 0.5% hysteresis, ensuring stable threshold behavior over temperature.

It implements a dual-mode watchdog timer: a 35s minimum startup delay after reset enables full system initialization, followed by a 1.12s minimum normal-mode timeout. The WDI input clears the timer on any edge, and the push-pull WDO output asserts low on timeout without external pullup.

Key Specifications

Pinout & Package

MAX6733AUTSHD3+ is housed in a 6-pin SOT23-6 package (U6-1 code), with 0.95mm pitch, 1.6mm width, and 2.9mm length. The package is lead-free (+T suffix) and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-voltage supervisor applications.

Compared with MAX6733AUTSHD3+, MAX6732AUTSHD3+ offers identical monitoring but requires external pullup for RST, while TPS3808G33DBVR reduces supply current by 82% but sacrifices VCC2 supervision-making it viable only when secondary rail reliability is managed elsewhere.

Availability

MAX6733AUTSHD3+ is available at Aetrix Electronics and suitable for telecom power sequencing, industrial PLC controllers, portable medical monitors, and automotive infotainment head units requiring stable component supply across extended temperature ranges.

Supply support for MAX6733AUTSHD3+ 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 MAX6730A–MAX6735A family delivers multivoltage µP supervision with integrated watchdog functionality, targeting systems requiring robust power-on reset, brownout protection, and software lockup recovery in harsh thermal environments.

FAQ

What are the exact reset threshold voltages for MAX6733AUTSHD3+?

The MAX6733AUTSHD3+ has factory-set reset thresholds of +2.925V (VCC1, SH suffix) and +1.313V (VCC2, SH suffix), with ±1.5% tolerance over –40°C to +125°C. These values are laser-trimmed during production and specified in the Electrical Characteristics table of the datasheet. The MAX6733AUTSHD3+ does not support adjustable thresholds - only the MAX6734A/MAX6735A variants include RSTIN.

Does MAX6733AUTSHD3+ support manual reset functionality?

Yes, MAX6733AUTSHD3+ includes an active-low manual reset input (MR) with internal 50kΩ pullup to VCC1. Driving MR low forces immediate RST assertion for the full reset timeout period (140–280ms). The MR pin accepts standard CMOS logic levels and tolerates pulses as short as 1µs, making it compatible with pushbutton switches or FPGA GPIO without external debounce.

What is the watchdog behavior of MAX6733AUTSHD3+ during power-up?

Upon power-up or reset assertion, MAX6733AUTSHD3+ enters a 35s minimum initial watchdog mode (tWD-L), allowing ample time for system initialization. After this period expires-or after the first valid edge on WDI-the watchdog transitions to its normal 1.12s minimum timeout (tWD-S). This dual-mode architecture prevents premature timeouts during boot while enabling rapid fault detection during runtime.

Can MAX6733AUTSHD3+ monitor a third voltage rail?

No, MAX6733AUTSHD3+ monitors exactly two fixed supply rails (VCC1 and VCC2) and does not include the RSTIN input. Only the MAX6734A and MAX6735A variants provide a third adjustable comparator input (RSTIN) referenced to an internal 626mV threshold. For triple-voltage supervision, select MAX6734AKASHD3+ or MAX6735AKASHD3+ instead of MAX6733AUTSHD3+.

What package and lead finish does MAX6733AUTSHD3+ use?

MAX6733AUTSHD3+ is supplied in a 6-pin SOT23-6 package (U6-1 code) with lead-free (RoHS-compliant) finish. The "+" in the part number explicitly denotes lead-free packaging per Maxim's ordering convention. The package measures 2.9mm × 1.6mm × 1.1mm and supports reflow soldering per JEDEC J-STD-020.