Analog Devices Inc./Maxim Integrated MAX6734KAVHD3+T

Overview

MAX6734KAVHD3+T from Maxim Integrated is a triple-voltage microprocessor supervisor IC with active-low open-drain reset and watchdog outputs, monitoring VCC1 (4.625V nominal), VCC2 (3.075V nominal), and an adjustable RSTIN input (626mV threshold), featuring 140ms–280ms reset timeout and -40°C to +85°C operation. It ensures reliable system initialization and fault recovery in multivoltage embedded systems.

For engineers reviewing the MAX6734KAVHD3+T datasheet, MAX6734KAVHD3+T pinout, MAX6734KAVHD3+T application, or MAX6734KAVHD3+T equivalent, key selection criteria include dual fixed-voltage thresholds, third adjustable supply monitoring, manual reset support, independent watchdog output timing (35s startup / 1.12s normal), and SOT23-8 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX6734KAVHD3+T integrates three independent voltage monitors: two factory-set comparators for VCC1 and VCC2 (suffix "VH" = 4.625V / 3.075V), plus a high-impedance RSTIN input referenced to a precise 626mV internal bandgap. Its reset logic asserts RST low when any monitored voltage falls below its threshold, with hysteresis of 0.5% and guaranteed validity down to VCC ≥ +0.8V.

The watchdog subsystem features dual-mode timing: a 35s minimum startup delay after reset enables full system boot, followed by a 1.12s minimum normal timeout period triggered by WDI edge transitions. The open-drain WDO output deasserts only after all supplies exceed thresholds or MR is asserted - no automatic recovery on timeout alone.

Key Specifications

Pinout & Package

MAX6734KAVHD3+T is housed in an 8-pin SOT23 package (K8SN+1 outline), measuring 2.9mm × 1.6mm × 1.1mm, with exposed pad not electrically connected. Pin 1 is marked by a dot; device orientation follows JEDEC MO-178 standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6734KAVHD3+T, MAX6734KATGD3+T shifts VCC2 monitoring to 1.665V for low-voltage secondary rails, while MAX6735KAVHD3+T replaces open-drain outputs with push-pull drivers - both retain identical timing, temperature range, and RSTIN functionality but address distinct system-level interface and supply architecture needs.

Availability

MAX6734KAVHD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, medical diagnostics, and automotive infotainment systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6734KAVHD3+T 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, sensing, connectivity, and security applications, serving industrial, automotive, communications, and computing markets.

The MAX6730–MAX6735 family delivers integrated voltage supervision and watchdog functionality for microprocessor-based systems, targeting applications demanding high reliability, low power, and minimal external component count in compact form factors.

FAQ

What are the exact factory-set reset thresholds for MAX6734KAVHD3+T?

The MAX6734KAVHD3+T has VCC1 threshold = 4.625V (V suffix) and VCC2 threshold = 3.075V (H suffix), per Table 1 in the datasheet. These are precise factory-trimmed values with ±125mV tolerance. The RSTIN input uses a fixed 626mV internal reference, enabling external resistor dividers to monitor higher voltages - for example, a 1:1 divider monitors +1.252V.

Does MAX6734KAVHD3+T support manual reset, and how is it implemented?

Yes, MAX6734KAVHD3+T includes an active-low manual reset input (MR) on pin 4. It features an internal 50kΩ pullup to VCC1, so leaving MR unconnected defaults to inactive. Driving MR low forces immediate RST assertion and clears the watchdog timer. The reset remains active for the full D3 timeout period (140–280ms) after MR returns high, ensuring robust system restart.

How does the watchdog timer operate in MAX6734KAVHD3+T during power-up?

Upon power-up or reset, MAX6734KAVHD3+T enters a 35s minimum watchdog startup delay (tWD-L), allowing complete system initialization before watchdog enforcement begins. After this period expires - or after the first valid WDI edge - it switches to normal mode with 1.12s minimum timeout (tWD-S). This dual-mode behavior prevents false timeouts during boot while enabling rapid hang detection thereafter.

What is the function of the RSTIN pin on MAX6734KAVHD3+T, and what voltage range can it monitor?

RSTIN (pin 5) is a high-impedance comparator input with a fixed 626mV internal reference. It monitors a third supply voltage by comparing the applied voltage to this threshold. Using an external resistor divider, MAX6734KAVHD3+T can supervise voltages from +0.63V up to VCC1 (max +5.5V). For instance, a 2:1 divider enables monitoring of +1.252V with 626mV at RSTIN.

Is MAX6734KAVHD3+T compatible with bidirectional microprocessor reset pins?

Yes, MAX6734KAVHD3+T's open-drain RST output (pin 1) is inherently compatible with bidirectional μP reset I/O pins. To prevent contention, connect a 10kΩ series resistor between RST and the μP's reset pin. This limits current during simultaneous drive and avoids logic conflicts - a configuration explicitly validated in the datasheet's Figure 5.