Monolithic Power Systems Inc. MPQ6411GS-AEC1-Z

Overview

MPQ6411GS-AEC1-Z from Monolithic Power Systems is a windowed watchdog timer IC qualified to AEC-Q100 Grade 1 for automotive applications. It monitors microcontroller health by enforcing strict timing windows on trigger signals (WDI), delivers power-on and undervoltage reset (WDO low-active), supports programmable short/long window modes via MODE pin, and operates from 5V supply. It is used in engine control units to prevent MCU lockup during critical runtime.

For engineers reviewing the MPQ6411GS-AEC1-Z datasheet, MPQ6411GS-AEC1-Z pinout, MPQ6411GS-AEC1-Z application, or MPQ6411GS-AEC1-Z equivalent, this page provides verified functional context, SOIC-8 package mapping, timing window values (t2–t5), WDO reset pulse width (t6), and AEC-Q100-compliant operating range (–40°C to +125°C).

Technical Context

The MPQ6411 implements a state-machine-based windowed watchdog with two distinct timing regimes: short window mode (MODE = low) uses t2 = 15 cycles and t3 = 10 cycles; long window mode (MODE = high) uses t4 = 1500 cycles and t5 = 1000 cycles - all referenced to an internal 880 µs base period set by RTIMER = 51 kΩ. The device enters sync signal monitoring state upon power-up or timeout, requiring WDI_OK pulse (10–5000 µs) within t1 = 450 cycles to resume normal operation.

WDO output behavior differs by variant: MPQ6411 (5V version) uses an inverter output, while MPQ6411-33 (3.3V) requires external pull-up; this part is the 5V AEC-Q100 variant. /WD_DIS enables hardware disable with weak internal pull-up, and GND-referenced VCC monitoring triggers VPOR-HIGH = 4.6 V (typ) and VPOR-LOW = 4.5 V (typ) reset assertion.

Key Specifications

Pinout & Package

MPQ6411GS-AEC1-Z is housed in a standard SOIC-8 package (JEDEC MS-012, variation AA), with 1.27 mm lead pitch, 3.9 mm body width, and 4.9 mm body length. Pin 1 is marked by a notch or dot; leads are gull-wing, coplanarity ≤ 0.10 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP380LSN33T2G and TPS3808G33DBVR, MPQ6411GS-AEC1-Z uniquely delivers AEC-Q100-qualified windowed supervision with user-selectable timing windows, hardware disable, and integrated POR - making it the only viable choice for ISO 26262 ASIL-B/C automotive subsystems requiring dual-bound fault detection.

Availability

MPQ6411GS-AEC1-Z is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, and electric power steering controllers requiring stable component supply across automotive production lifecycles.

Supply support for MPQ6411GS-AEC1-Z 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.

The MPQ6411 belongs to MPS's automotive-grade watchdog timer product line, engineered specifically for functional safety compliance in ASIL-B/C systems including powertrain, chassis, and ADAS domains.

FAQ

What is the exact reset pulse width (t6) for MPQ6411GS-AEC1-Z at RTIMER = 51 kΩ?

The reset pulse width t6 is specified as 4 cycles, which translates to approximately 3.52 µs when RTIMER = 51 kΩ (base period T = 880 µs). This value is derived from bench characterization and is consistent across –40°C to +125°C operating range.

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

No. Unlike the 3.3V MPQ6411-33 variant, the MPQ6411GS-AEC1-Z (5V version) features an inverter-output WDO stage and does not require an external pull-up resistor. WDO actively drives low during reset and high-impedance otherwise.

How is the watchdog window timing affected by temperature or supply variation?

Window timing scales linearly with the base period T, which varies ±10% over temperature and supply per datasheet Figure 4–6. At RTIMER = 51 kΩ, T ranges from 792 µs to 968 µs; thus t2–t6 scale proportionally but retain fixed cycle ratios.

Can /WD_DIS be left floating in a production design?

Yes. /WD_DIS has a weak internal pull-up, so the watchdog remains enabled by default when the pin is unconnected. However, for robustness in noisy automotive environments, tying it to VCC via a 10 kΩ resistor is recommended.

What happens if WDI remains low beyond the maximum WDI_OK pulse width?

If WDI stays low longer than 5000 µs, the device interprets it as a WDI error and holds WDO low continuously until WDI returns high. This failsafe behavior prevents MCU from escaping reset due to sustained invalid input.

Is the NC pin (Pin 5) electrically isolated or internally bonded?

Pin 5 is confirmed as No Connect - not internally bonded or electrically connected. It must remain unpopulated and unconnected on the PCB to prevent noise coupling or unintended current paths.

How does the MPQ6411 handle brown-out conditions below VPOR-LOW?

When VCC falls below VPOR-LOW (4.5 V typ), WDO is asserted low again to reinitiate MCU reset. This ensures continuous supervision during supply sag, such as during cranking or load-dump transients in automotive electrical systems.