Analog Devices Inc./Maxim Integrated MAX6753KA46+T

Overview

MAX6753KA46+T from Analog Devices is a window watchdog supervisory IC for microprocessor systems, featuring factory-trimmed 4.625V ±2% VCC reset threshold, adjustable slow/fast watchdog timeout via external capacitor and pin-strapped ratio (8×/16×/64×), push-pull active-low RESET output, and operation over -40°C to +125°C. It monitors single supply voltage and asserts reset on VCC brownout, manual reset, or watchdog fault-used in automotive engine control units requiring AEC-Q100-compliant power sequencing and fault detection.

For engineers reviewing the MAX6753KA46+T datasheet, MAX6753KA46+T pinout, MAX6753KA46+T application, or MAX6753KA46+T equivalent, key selection criteria include its windowed watchdog architecture (tWD1/tWD2 timing windows), SOT23-8 package compatibility with space-constrained PCBs, guaranteed RESET validity down to VCC ≥ 1V, and support for dual-voltage monitoring when paired with external resistor dividers.

Technical Context

The MAX6753KA46+T implements a min/max (window) watchdog timer that detects both early and late transitions on WDI: fast faults occur when falling edges arrive faster than tWD1 (e.g., 121ms typ at CSWT = 1500pF, SET0/SET1 = low/low), slow faults when intervals exceed tWD2 (971ms typ). Reset assertion is triggered by VCC falling below 4.625V ±2%, RESET IN dropping below 1.235V, or MR pull-down.

Its internal ramp-based timeout generation uses SRT and SWT pins to set tRP = 4.94×10⁶ × CSRT (reset) and tWD2 = 0.65×10⁹ × CSWT (slow watchdog), with tWD1 selected via SET0/SET1 logic states. The device guarantees RESET assertion for ≥20µs after VCC transient events exceeding 100mV overdrive, and supports manual reset with 1µs minimum pulse width and 100ns glitch rejection.

Key Specifications

Pinout & Package

MAX6753KA46+T is housed in an 8-pin SOT23 package (Outline 21-0078), with 0.65mm pitch, 2.9mm × 1.6mm footprint, and thermal resistance θJA = 196°C/W on four-layer board. Pin 1 is WDI, pin 2 is SET1, pin 3 is GND, pin 4 is VCC, pin 5 is RESET, pin 6 is SWT, pin 7 is SRT, and pin 8 is RESET IN.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6752KA32+T and TPS3808G33DBVR, the MAX6753KA46+T uniquely combines 4.625V precision reset, AEC-Q100 qualification, and windowed watchdog in one SOT23-8 package-enabling single-chip compliance with automotive functional safety and brownout resilience requirements.

Availability

MAX6753KA46+T is available at Aetrix Electronics and suitable for automotive engine control, medical infusion pumps, industrial PLC modules, and battery-powered IoT gateways requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6753KA46+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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets with precision timing, power management, and sensing solutions.

The MAX6746–MAX6753 family was designed specifically for automotive and industrial microprocessor supervision, delivering AEC-Q100-qualified, ultra-low-power, windowed watchdog capability in miniature SOT23 packages for space- and reliability-constrained applications.

FAQ

What is the exact reset threshold voltage of the MAX6753KA46+T?

The MAX6753KA46+T features a factory-trimmed VCC reset threshold of 4.625V with ±2% tolerance over -40°C to +125°C. This value is confirmed in Table 2 of the datasheet under suffix "46", and applies specifically to the MAX6753KA46+T variant-not the broader MAX6753 family. The MAX6753KA46+T does not require external resistors to achieve this threshold, making it ideal for 5V system monitoring where precision brownout detection is critical.

Does the MAX6753KA46+T support dual-voltage monitoring?

The MAX6753KA46+T supports dual-voltage monitoring by using its RESET IN pin (pin 8) in conjunction with an external resistor divider to monitor a secondary voltage rail-while simultaneously monitoring VCC at 4.625V. Although the MAX6753 variant is not listed in the Selector Guide as having "Adjustable RESET Threshold", the datasheet explicitly confirms RESET IN functionality for MAX6752/MAX6753 in Pin Descriptions and Detailed Description sections. Thus, the MAX6753KA46+T can supervise both VCC and an externally derived voltage like a 2.5V analog reference.

How do I configure the window watchdog timeout periods for the MAX6753KA46+T?

The MAX6753KA46+T uses two independent timing elements: CSWT on SWT (pin 6) sets the slow watchdog period tWD2 (e.g., 971ms typ at 1500pF), while SET0 and SET1 pins select the fast watchdog ratio (tWD1 = tWD2 ÷ 8, ÷16, or ÷64). For example, with CSWT = 1500pF and SET0 = GND / SET1 = GND, tWD2 ≈ 971ms and tWD1 ≈ 121ms. The MAX6753KA46+T ignores WDI transitions occurring between tWD1(max) and tWD2(min), ensuring robust fault discrimination without spurious resets.

Is the MAX6753KA46+T pin-compatible with other devices in the MAX6746–MAX6753 family?

The MAX6753KA46+T uses the same SOT23-8 pinout as MAX6752, MAX6748–MAX6751, and MAX6746–MAX6747 variants, with identical pin assignments: WDI (1), SET1 (2), GND (3), VCC (4), RESET (5), SWT (6), SRT (7), RESET IN (8). However, functional differences exist-e.g., MAX6746 lacks SET0/SET1 and uses WDS instead-so direct substitution requires verification of watchdog mode, reset threshold, and pin strapping logic. The MAX6753KA46+T is not functionally interchangeable with MAX6746 or MAX6749 without schematic review.

What is the minimum supply voltage required for guaranteed RESET functionality in the MAX6753KA46+T?

The MAX6753KA46+T guarantees valid RESET output logic for VCC ≥ 1.0V, as stated in Absolute Maximum Ratings and Electrical Characteristics tables. Below 1.0V, RESET may become indeterminate due to declining sink current capability. For applications requiring RESET validity down to 0V, a 100kΩ pulldown resistor between RESET and GND is recommended-applicable only to push-pull variants like the MAX6753KA46+T, not open-drain versions. This ensures fail-safe low state during deep brownout.