Monolithic Power Systems Inc. MP6411GS-Z

Overview

MP6411GS-Z from Monolithic Power Systems is a windowed watchdog timer IC designed to monitor and reset microcontrollers in safety-critical embedded systems. It operates with 5V supply, supports programmable short/long window modes via MODE pin, delivers power-on reset at 4.4–4.8V, and outputs active-low reset (WDO) with 4-cycle pulse width. Used in automotive ECUs where deterministic fault recovery is required.

For engineers reviewing the MP6411GS-Z datasheet, MP6411GS-Z pinout, MP6411GS-Z application, or MP6411GS-Z equivalent, key selection factors include window timing resolution (±10% at 880µs), /WD_DIS disable control, SOIC-8 thermal performance (θJA = 96°C/W), and VCC-dependent POR thresholds for 5V systems.

Technical Context

The MP6411GS-Z implements a state-machine-based windowed watchdog with two distinct timing windows controlled by the MODE pin: short mode (t2=15 cycles, t3=10 cycles) and long mode (t4=1500 cycles, t5=1000 cycles), both referenced to an external RTIMER resistor. Its WDI_OK detection logic validates MCU synchronization pulses between 10µs–5ms duration.

Power-on reset is generated when VCC rises above 4.4V (typ. 4.6V), holding WDO low for t0 = 10 cycles (~8.8ms at RTIMER=51kΩ). The /WD_DIS pin provides hardware-level watchdog disable with weak internal pull-up, enabling fail-safe configuration without external biasing.

Key Specifications

Pinout & Package

MP6411GS-Z is housed in an industry-standard SOIC-8 package (5.0mm × 6.2mm, 1.27mm pitch), optimized for automated assembly and thermal management in high-reliability applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6373KA+T and TPS3823DBVR, MP6411GS-Z uniquely provides dual-mode windowed supervision, hardware disable (/WD_DIS), and tighter POR hysteresis-critical for ISO 26262 ASIL-B systems requiring layered fault detection.

Availability

MP6411GS-Z is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC main controllers, and railway signaling interface modules requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MP6411GS-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 MP6411 belongs to MPS's system-supervision product line, engineered specifically for functional-safety-critical applications in automotive and industrial markets requiring precise, configurable watchdog behavior.

FAQ

What is the exact power-on reset threshold voltage for MP6411GS-Z?

The MP6411GS-Z asserts WDO low when VCC rises to 4.4V (min), releases it at 4.6V (typ), and reasserts at 4.3V (min) during falling VCC-providing 0.1–0.2V hysteresis to prevent chatter during brown-out conditions. This threshold is fixed for the 5V variant and not adjustable.

How does the MODE pin affect watchdog timing resolution?

When MODE is pulled low, the watchdog enters short window mode with t2=15 cycles and t3=10 cycles (total 25 cycles ≈ 22ms at RTIMER=51kΩ). When MODE is high, it switches to long window mode with t4=1500 cycles and t5=1000 cycles (total 2500 cycles ≈ 2.2s), enabling tiered fault detection sensitivity.

Can MP6411GS-Z be used with a 3.3V microcontroller?

Yes-the WDI, MODE, and /WD_DIS inputs accept 3.3V logic levels (VIH=2.1V min, VIL=0.6V max), and WDO is open-drain compatible with 3.3V pull-up. However, VCC must be 5V; the MP6411GS-Z is not rated for 3.3V supply operation.

What happens if the WDI signal remains low longer than 5ms?

If WDI stays low beyond 5ms, the MP6411GS-Z interprets this as a MCU lockup and immediately pulls WDO low until WDI returns high-bypassing normal window timing and forcing immediate reset, which is critical for detecting stuck states in safety-critical firmware.

Is the TIMER pin internally biased or does it require an external resistor?

The TIMER pin requires an external resistor (RTIMER) to ground-no internal biasing exists. For example, a 51kΩ resistor sets the base period to ~880µs. The relationship is linear: T(µs) = 15.75 × RTIMER(kΩ) + 73.5, enabling precise timing calibration.

Does MP6411GS-Z support watchdog disable during firmware updates?

Yes-driving /WD_DIS low disables the watchdog entirely, allowing safe firmware flashing or debug sessions without triggering spurious resets. The pin has a weak internal pull-up, so leaving it unconnected defaults to enabled operation.

What is the maximum allowable junction temperature for continuous operation?

The MP6411GS-Z is rated for continuous operation up to +125°C junction temperature. With θJA = 96°C/W and ambient temperature of +85°C, maximum allowable power dissipation is 0.43W-well below the SOIC-8 package limit of 1.3W at +25°C ambient.