Monolithic Power Systems Inc. MPQ6411GS-AEC1

Overview

MPQ6411GS-AEC1 from Monolithic Power Systems is an AEC-Q100 Grade 1 qualified windowed watchdog timer IC designed to monitor and reset automotive microcontrollers. It operates with 5V supply, supports programmable short/long window modes via MODE pin, delivers power-on reset (VPOR-HIGH = 4.4–4.8V), and outputs active-low reset (WDO) during power-up or undervoltage. Used in engine control units and ADAS domain controllers for fail-safe MCU supervision.

For engineers reviewing the MPQ6411GS-AEC1 datasheet, MPQ6411GS-AEC1 pinout, MPQ6411GS-AEC1 application, or MPQ6411GS-AEC1 equivalent, key selection criteria include window timing resolution (t2 = 15 cycles, t4 = 1500 cycles), /WD_DIS disable functionality, SOIC-8 package compatibility, and AEC-Q100 Grade 1 temperature range (-40°C to +125°C).

Technical Context

The MPQ6411GS-AEC1 implements a state-machine-based windowed watchdog with two distinct timing windows-short mode (t2/t3 = 15/10 cycles) and long mode (t4/t5 = 1500/1000 cycles)-both derived from external TIMER resistor (RTIMER = 51kΩ typical). Its WDI synchronization logic enforces strict pulse-width compliance (10–5000 µs) and detects stuck-low errors.

Power-on reset is generated at VPOR-HIGH (4.4–4.8V) with fixed t0 delay (~10 cycles), while WDO output behavior differs by variant: MPQ6411GS-AEC1 uses internal inverter drive (no pull-up required), unlike open-drain MPQ6411GS-33-AEC1. MODE and /WD_DIS pins feature weak internal pull-ups, enabling default-enabled operation with minimal external components.

Key Specifications

Pinout & Package

MPQ6411GS-AEC1 is housed in an industry-standard SOIC-8 package (JEDEC MS-012 AA), 3.9mm × 4.9mm body, 1.27mm lead pitch, with gull-wing leads and RoHS-compliant matte tin plating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar windowed watchdog timer applications.

Compared with PCF2129AT and TLE42754, MPQ6411GS-AEC1 provides true windowed supervision with dual-mode timing, explicit disable control, and SOIC-8 footprint compatibility - making it uniquely suitable for ASIL-B–aligned automotive MCU monitoring where false-reset immunity is critical.

Availability

MPQ6411GS-AEC1 is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, and body control modules requiring stable component supply with full AEC-Q100 traceability and automotive-grade lifecycle support.

Supply support for MPQ6411GS-AEC1 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MPQ6411 belongs to MPS's automotive-grade watchdog timer product line, engineered specifically for functional safety-critical MCU supervision in AEC-Q100 environments - emphasizing timing precision, fault resilience, and seamless integration with existing 5V automotive power domains.

FAQ

What is the recommended external TIMER resistor value for MPQ6411GS-AEC1?

The datasheet specifies RTIMER = 51kΩ as the typical value, yielding a base period T ≈ 880 µs. This sets short-mode windows to t2 = 15 cycles and t3 = 10 cycles, and long-mode windows to t4 = 1500 cycles and t5 = 1000 cycles. Deviations alter all timing proportionally per T = 15.75 × RTIMER(kΩ) + 73.5 µs.

Does MPQ6411GS-AEC1 require an external pull-up on WDO?

No. Unlike the 3.3V MPQ6411GS-33-AEC1 variant, MPQ6411GS-AEC1 uses an internal inverter output for WDO and does not require an external pull-up resistor when used with 5V systems. This simplifies layout and reduces BOM count.

How does the /WD_DIS pin behave when left unconnected?

The /WD_DIS pin has a weak internal pull-up, so leaving it unconnected defaults the watchdog to enabled state. To disable the watchdog, actively drive /WD_DIS low (≤0.8V); pulling it high (≥3.2V) or leaving it floating maintains normal operation.

What happens if the WDI signal stays low longer than 5000 µs?

The device detects this as a WDI error and pulls WDO low continuously until WDI returns high. This latched reset condition prevents MCU recovery until the fault is cleared - ensuring persistent fault signaling for diagnostics and fail-safe shutdown.

Is the MODE pin compatible with 3.3V logic levels when used with a 5V VCC supply?

Yes. MODE logic thresholds are referenced to VCC: logic high is ≥3.2V and logic low is ≤0.8V under 5V operation. A 3.3V GPIO can reliably set MODE = high (3.3V > 3.2V) or MODE = low (if pulled to GND), supporting mixed-voltage system interfacing.

What is the power-on reset delay (t0) and how is it determined?

t0 is fixed at ~10 cycles of the internal oscillator and occurs after VCC crosses VPOR-HIGH (4.4–4.8V). It is not user-adjustable and ensures the MCU receives a clean, timed reset pulse before executing code - independent of external components or configuration pins.

Can MPQ6411GS-AEC1 be used in non-automotive industrial applications?

Yes. While AEC-Q100 qualified, its -40°C to +125°C operating range, low IQ (16–19 µA), and robust windowed timing make it suitable for industrial PLCs, medical infusion pumps, and telecom edge equipment where deterministic MCU supervision is required.