Monolithic Power Systems Inc. MPQ6411GS-33

Overview

MPQ6411GS-33 from Monolithic Power Systems is a windowed watchdog timer IC designed for automotive and industrial microcontroller supervision. It delivers 3.3V supply compatibility, AEC-Q100 Grade 1 qualification, programmable short/long window modes (t2/t3 = 15/10 cycles or t4/t5 = 1500/1000 cycles at RTIMER = 51kΩ), and power-on reset with VPOR-HIGH = 2.9–3.1V and VPOR-LOW = 2.8–3.0V. It operates across –40°C to +125°C junction temperature in SOIC-8 package.

For engineers reviewing the MPQ6411GS-33 datasheet, MPQ6411GS-33 pinout, MPQ6411GS-33 application, or MPQ6411GS-33 equivalent, this device supports critical fail-safe timing supervision where precise window-based trigger validation, low-quiescent-current operation (10–14µA typ. at RTIMER = 100kΩ), and open-drain WDO output with external pull-up are required.

Technical Context

The MPQ6411GS-33 implements a state-machine-based windowed watchdog architecture with two distinct operational modes controlled by the MODE pin. Its timing is resistor-programmable via the TIMER pin (RTIMER = 51kΩ yields ~880µs single period), and it features dedicated sync signal monitoring (t1 = 450 cycles) before entering window evaluation.

It integrates power-on reset generation with hysteresis (VPOR-HIGH/VPOR-LOW separation ≥0.1V), watchdog disable (/WD_DIS active-low with internal weak pull-up), and WDI error detection (WDI low >5ms triggers continuous WDO assertion). WDO is open-drain, requiring external pull-up (e.g., 100kΩ), unlike the push-pull variant in 5V versions.

Key Specifications

Pinout & Package

MPQ6411GS-33 is housed in an industry-standard SOIC-8 package (5.0mm × 6.2mm, 1.27mm pitch) with exposed pad not present and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP380LSN33T1G and TPS3808G33DBVR, MPQ6411GS-33 uniquely provides true windowed supervision with dual-mode configurability, lower quiescent current, and AEC-Q100 qualification-making it the only choice for ASIL-capable automotive MCU supervision where timing precision and fault discrimination are mandatory.

Availability

MPQ6411GS-33 is available at Aetrix Electronics and suitable for automotive ECU development, ADAS module integration, and industrial PLC CPU board production requiring stable component supply and long-term lifecycle assurance.

Supply support for MPQ6411GS-33 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 product line delivers AEC-Q100-qualified windowed watchdog timers optimized for functional safety-critical MCU supervision in automotive and industrial control systems-emphasizing timing accuracy, low power, and robust fault detection.

FAQ

What is the exact WDO reset pulse width for MPQ6411GS-33?

The WDO reset pulse width (t6) is 4 cycles of the internal timer clock, which equals 4 × 880µs ≈ 3.52ms when RTIMER = 51kΩ. This fixed duration ensures sufficient MCU reset hold time regardless of window mode or trigger timing, and is derived from bench characterization per the datasheet.

Can MPQ6411GS-33 be used with a 5V MCU system?

No-MPQ6411GS-33 is strictly a 3.3V-supply device (VCC = 3.3V ±10%). Its input thresholds (WDI/MODE//WD_DIS high = 2.1V min) and WDO open-drain structure assume 3.3V logic levels. For 5V systems, use MPQ6411GS (5V version) or add level-shifting circuitry, which compromises reliability and increases BOM cost.

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. This eliminates the need for an external pull-up resistor in most designs, simplifying layout while maintaining fail-safe operation-disabled only when actively pulled low by system logic.

What happens if the WDI signal stays low longer than the maximum allowed pulse width?

If WDI remains low for >5ms, the device detects a WDI error and pulls WDO low continuously until WDI returns high. This latched response prevents MCU recovery attempts from masking persistent firmware faults-ensuring hard reset escalation rather than transient glitch tolerance.

Is the TIMER pin compatible with standard 1% metal-film resistors?

Yes-the TIMER pin interfaces with standard 1% tolerance metal-film resistors (e.g., 51kΩ). The timing equation T(µs) = 15.75 × RTIMER(kΩ) + 73.5 shows linear dependence, so 1% RTIMER yields <1% timing variation, meeting typical watchdog window tolerance requirements without calibration.

Does MPQ6411GS-33 require an external pull-up on WDO, and what value is recommended?

Yes-WDO is open-drain and requires an external pull-up. The datasheet recommends 100kΩ to VCC (3.3V), providing optimal trade-off between rise time (<1µs), leakage current (<33nA), and noise immunity. Lower values increase power draw; higher values risk slow edges in noisy environments.

How does the MODE pin affect watchdog behavior during runtime?

The MODE pin is sampled continuously-not latched at startup-so changing MODE from low to high during operation transitions the watchdog from short to long window mode within one timer cycle. This enables dynamic adaptation to different firmware execution phases (e.g., bootloader → application).