Monolithic Power Systems Inc. MPQ6411GS-33-AEC1-Z

Overview

MPQ6411GS-33-AEC1-Z from Monolithic Power Systems is a windowed watchdog timer IC designed for automotive microcontroller supervision. It delivers programmable short/long window modes (t2/t3 = 15/10 cycles or t4/t5 = 1500/1000 cycles at RTIMER = 51kΩ), power-on reset with 2.9–3.1V POR threshold, and AEC-Q100 Grade 1 qualification for operation from −40°C to +125°C. Its SOIC-8 package supports 3.3V VCC systems in engine control units and ADAS domain controllers.

For engineers reviewing the MPQ6411GS-33-AEC1-Z datasheet, MPQ6411GS-33-AEC1-Z pinout, MPQ6411GS-33-AEC1-Z application, or MPQ6411GS-33-AEC1-Z equivalent, key selection criteria include its open-drain WDO output requiring external pull-up, MODE-selectable timing windows, /WD_DIS disable function, and low 10–18µA quiescent current at 3.3V.

Technical Context

The MPQ6411GS-33-AEC1-Z implements a state-machine-based windowed watchdog with two distinct timing regimes controlled by the MODE pin. Its internal logic monitors WDI synchronization pulses against dynamically defined open and close windows-short mode uses 15-cycle close / 10-cycle open intervals, long mode uses 1500/1000 cycles-both derived from RTIMER = 51kΩ.

It integrates power-on reset generation with hysteresis (VPOR-HIGH = 2.9–3.1V, VPOR-LOW = 2.8–3.0V) and fault detection for sustained WDI low states exceeding 5ms. The /WD_DIS pin provides hardware-level watchdog disable with weak internal pull-up, enabling fail-safe MCU initialization sequences.

Key Specifications

Pinout & Package

MPQ6411GS-33-AEC1-Z is housed in an industry-standard SOIC-8 package (JEDEC MS-012, variation AA), with 1.27mm pitch, 3.9mm body width, and 4.9mm length. Pin 1 marked via notch or bevel; leads coplanar within 0.10mm.

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-33-AEC1-Z uniquely combines MODE-selectable window timing, hardware disable, and AEC-Q100 Grade 1 in SOIC-8-making it the only choice for ASIL-B-compliant automotive MCUs requiring adaptive supervision.

Availability

MPQ6411GS-33-AEC1-Z is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, body control modules, and electric power steering systems requiring stable component supply across automotive production lifecycles.

Supply support for MPQ6411GS-33-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 product line delivers AEC-Q100-qualified windowed watchdog timers targeting functional safety requirements in automotive ECUs, ADAS, and electrification systems-designed to replace discrete reset ICs with integrated, configurable supervision.

FAQ

What is the minimum external TIMER resistor value supported?

The datasheet specifies RTIMER = 51kΩ as the reference for timing characterization, but the functional block diagram and timing equations support values down to ~10kΩ. At lower resistances, single-period T decreases linearly (T ≈ 15.75 × RTIMER + 73.5 µs), enabling sub-millisecond windows. Layout parasitics and noise immunity should be verified for values below 20kΩ.

How does the /WD_DIS pin behave during power-up?

/WD_DIS has a weak internal pull-up, so the watchdog remains enabled by default during power-up. No external pull-up is required. If external control is needed, drive /WD_DIS low only after VCC stabilizes above 2.8V to avoid metastability; the pin accepts 3.3V logic levels and draws ≤6µA when pulled low.

Can WDO be directly connected to a 5V-tolerant MCU reset pin?

No-WDO is open-drain and rated for 3.3V operation. Connecting it directly to a 5V reset pin risks latch-up or damage. Use a level-shifting pull-up resistor (e.g., 100kΩ to 3.3V) or a dedicated level translator. The WDO sink current capability (1mA) supports standard 3.3V reset thresholds.

What happens if MODE is left floating?

MODE has a weak internal pull-up, so it defaults to high-activating long window mode (t4/t5 = 1500/1000 cycles). This is safe for initial bring-up but may cause missed resets in fast-firmware applications. For deterministic behavior, explicitly tie MODE to VCC (long) or GND (short) with a 10kΩ resistor.

Is the POR hysteresis sufficient for automotive battery transients?

Yes-the 100mV hysteresis (VPOR-HIGH = 2.9–3.1V, VPOR-LOW = 2.8–3.0V) exceeds typical ISO 16750-2 pulse 4a/b requirements. Combined with the t0 delay (10 cycles ≈ 8.8ms at RTIMER = 51kΩ), it prevents chatter during slow-rising battery recovery after cranking.

Does the MPQ6411GS-33-AEC1-Z support watchdog window reconfiguration during runtime?

Yes-changing MODE from high to low (or vice versa) dynamically switches between long and short window modes without reset. The state machine transitions cleanly: e.g., a rising MODE edge during long-window open state immediately begins counting toward the new short-window close time (t2), ensuring continuous supervision.

What is the maximum allowable WDI pulse width before triggering an error?

The datasheet specifies WDI_OK pulse width from 10µs to 5ms. Pulses longer than 5ms are treated as errors: WDO is held low until WDI returns high. This protects against stuck-at-low faults in MCU GPIO drivers and ensures immediate recovery from driver-level failures.