Monolithic Power Systems Inc. MP6411GS-33-Z

Overview

MP6411GS-33-Z from Monolithic Power Systems is a 3.3V windowed watchdog timer IC designed to monitor microcontroller health and assert a reset signal on fault or timeout. It operates in programmable short/long window modes, features power-on reset (POR) at 2.9–3.1V, supports external timing resistor (RTIMER = 51kΩ yields ~880µs period), and delivers open-drain WDO output requiring external pull-up. Used in automotive and industrial control systems where deterministic MCU supervision is critical.

For engineers reviewing the MP6411GS-33-Z datasheet, MP6411GS-33-Z pinout, MP6411GS-33-Z application, or MP6411GS-33-Z equivalent, key selection considerations include its 3.3V supply compatibility, MODE-selectable window timing (t2/t3 = 15/10 cycles short mode; t4/t5 = 1500/1000 cycles long mode), /WD_DIS disable function, low quiescent current (10–14µA typ. at RTIMER = 100kΩ), and SOIC-8 package with NC pin.

Technical Context

The MP6411GS-33-Z implements a state-machine-based windowed watchdog with three core operational phases: sync signal monitoring (t1 = 450 cycles), window open/close evaluation (mode-dependent cycle counts), and reset pulse generation (t6 = 4 cycles). Its internal POR circuit asserts WDO low during VCC ramp-up until VPOR-HIGH (2.9–3.1V) is reached, then holds reset for t0 (10 cycles) before releasing.

Timing is resistor-programmable via TIMER pin: T ≈ (15.75 × RTIMER + 73.5) µs. The /WD_DIS pin enables hardware disable with weak internal pull-up; MODE pin selects window length with internal pull-up; WDI_OK detection requires WDI low for 10µs–5ms to validate MCU synchronization.

Key Specifications

Pinout & Package

MP6411GS-33-Z is housed in an 8-pin SOIC package (JEDEC MS-012 AA, 1.27mm pitch) with exposed pad not connected. Pin 5 is NC (no internal connection); all other pins are functional per datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6373KA+T and TPS3823-33DBVR, MP6411GS-33-Z uniquely combines 3.3V operation, resistor-programmable timing, and dual-mode windowed supervision - enabling precise alignment with MCU task scheduling in safety-critical embedded systems.

Availability

MP6411GS-33-Z is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC main controllers, railway signaling interface modules, and medical infusion pump controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MP6411GS-33-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, and global manufacturing partnerships.

The MP6411 belongs to MPS's system-supervision product line, engineered specifically for deterministic, hardware-enforced MCU monitoring in automotive and industrial environments where functional safety and timing predictability are mandatory.

FAQ

What is the exact power-on reset behavior of MP6411GS-33-Z?

MP6411GS-33-Z asserts WDO low when VCC rises above 1V, holds it low until VCC reaches VPOR-HIGH (2.9–3.1V), then maintains reset for t0 = 10 internal cycles (~8.8ms at RTIMER = 51kΩ) before releasing WDO high. This ensures full MCU power stabilization and internal register initialization before release.

How does the /WD_DIS pin affect watchdog operation?

Pulling /WD_DIS low disables the watchdog timer entirely - no window evaluation, no reset assertion, and no WDI monitoring occur. With /WD_DIS open, the internal weak pull-up enables normal operation. This allows hardware-controlled watchdog suspension during firmware updates without software coordination.

Can MP6411GS-33-Z be used with a 5V MCU system?

Yes, but only for the WDO output interface: MP6411GS-33-Z's WDO is open-drain and must be pulled up to the MCU's 5V supply (not VCC). Its VCC pin remains strictly 3.3V, and WDI/MODE//WD_DIS inputs tolerate 5V logic levels per datasheet (VIH = 2.1V min, VIL = 0.6V max).

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

If WDI stays low beyond 5ms (max WDI_OK pulse width), the device interprets this as a WDI error and forces WDO low continuously until WDI returns high. This failsafe prevents false timeouts due to stuck-low signals and ensures immediate reset on persistent communication faults.

Is the NC pin (Pin 5) required to be left floating?

Yes - Pin 5 is internally unconnected. It must not be soldered to any net, including ground or VCC. Leaving it floating is mandatory; connecting it risks unintended parasitic coupling or mechanical stress on the bond wire, potentially compromising reliability in high-vibration environments like automotive applications.

How does MODE pin selection affect timing resolution and fault coverage?

MODE = low configures short window mode (t2 = 15 cycles, t3 = 10 cycles), providing tighter timing validation ideal for high-frequency MCU tasks. MODE = high enables long window mode (t4 = 1500 cycles, t5 = 1000 cycles), increasing fault coverage for slower background processes. Switching MODE dynamically changes window size without reset.