Monolithic Power Systems Inc. MPQ6411GS-33-P

Overview

MPQ6411GS-33-P from Monolithic Power Systems is a windowed watchdog timer IC designed for automotive and industrial microcontroller supervision. It provides 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 threshold, and AEC-Q100 Grade 1 qualification. Its open-drain WDO output requires external pull-up and operates from 3.3V ±10% supply.

For engineers reviewing the MPQ6411GS-33-P datasheet, MPQ6411GS-33-P pinout, MPQ6411GS-33-P application, or MPQ6411GS-33-P equivalent, key selection criteria include window timing granularity, POR hysteresis (VPOR-HIGH − VPOR-LOW = 0.1V), /WD_DIS disable function, MODE pin logic thresholds (2.1V high / 0.6V low), and SOIC-8 thermal resistance (θJA = 96°C/W).

Technical Context

The MPQ6411GS-33-P implements a state-machine-based windowed watchdog with two distinct operational windows determined by the MODE pin. Its timing is resistor-programmable via the TIMER pin (T ≈ 0.88ms at RTIMER = 51kΩ) and includes dedicated sync monitoring (t1 = 450 cycles) to validate MCU health before entering window evaluation.

It integrates dual POR detection (rising-edge VPOR-HIGH = 2.9–3.1V, falling-edge VPOR-LOW = 2.8–3.0V), WDI error handling (WDI low >5ms triggers continuous WDO low), and low-quiescent-current operation (10–14µA typ. at RTIMER = 100kΩ). The /WD_DIS pin enables hardware-level watchdog disable with internal weak pull-up.

Key Specifications

Pinout & Package

MPQ6411GS-33-P is housed in a standard SOIC-8 package (5.0mm × 4.0mm, 1.27mm pitch) with exposed pad not present. Pin functions are validated per MPS datasheet Rev. 1.1 and support direct PCB layout integration with JEDEC MS-012 AA land pattern.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP3807ASN and TPS3808G33, MPQ6411GS-33-P uniquely delivers dual-mode windowed timing, hardware disable, and AEC-Q100 Grade 1 validation-making it the only option that satisfies ISO 26262 ASIL-B timing supervision requirements out-of-the-box.

Availability

MPQ6411GS-33-P is available at Aetrix Electronics and suitable for automotive ECUs, ADAS camera modules, and industrial PLC safety I/O requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MPQ6411GS-33-P 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-critical MCU supervision in AEC-Q100 environments with emphasis on timing precision, POR stability, and fault coverage.

FAQ

What is the exact power supply requirement for MPQ6411GS-33-P?

The MPQ6411GS-33-P requires a nominal 3.3V supply with ±10% tolerance (2.97V to 3.63V). Operation outside this range risks incorrect POR assertion, inaccurate window timing, or failure to meet AEC-Q100 Grade 1 specifications. The device draws 10–14µA typical quiescent current at 3.3V with RTIMER = 100kΩ.

How does the MODE pin affect watchdog timing behavior?

The MODE pin selects between short window mode (MODE = low) and long window mode (MODE = high). In short mode, the watchdog enforces t2 = 15 cycles and t3 = 10 cycles; in long mode, it uses t4 = 1500 cycles and t5 = 1000 cycles-all referenced to the base period set by RTIMER. Internal weak pull-up defaults to long mode if MODE is unconnected.

Is an external pull-up resistor required on the WDO pin?

Yes. WDO is an open-drain output and must be pulled up externally-typically with a 100kΩ resistor to VCC. This ensures proper logic-high level during normal operation and allows multiple watchdogs to share a common reset bus via wired-OR configuration, which is essential in complex automotive systems.

What happens if the WDI signal stays low longer than specified?

If WDI remains low for more than 5ms, the MPQ6411GS-33-P interprets this as a WDI error and forces WDO continuously low until WDI returns high. This behavior detects MCU lockup or signal line shorts without relying on software polling, providing robust hardware-level fault containment.

Can the /WD_DIS pin be left unconnected?

Yes. /WD_DIS has an internal weak pull-up, so leaving it unconnected defaults the watchdog to enabled state. However, for production systems requiring guaranteed disable capability (e.g., during firmware updates), it must be actively driven low via MCU GPIO or switch-never left floating in safety-critical paths.

What is the significance of the 0.1V POR hysteresis?

The 0.1V difference between VPOR-HIGH (2.9–3.1V) and VPOR-LOW (2.8–3.0V) prevents oscillatory reset assertion during slow or noisy VCC ramps. This hysteresis ensures the MCU receives a clean, single reset pulse during power-up and avoids repeated resets during brown-out conditions near the threshold.

Does MPQ6411GS-33-P support both rising- and falling-edge POR detection?

No. It performs rising-edge POR detection (WDO goes high when VCC crosses VPOR-HIGH) and falling-edge undervoltage detection (WDO goes low when VCC drops below VPOR-LOW). This dual-edge behavior provides complete power-rail supervision but does not respond to edge transitions other than those defined in the absolute maximum ratings table.