Monolithic Power Systems Inc. MP6411GS-33-P

Overview

MP6411GS-33-P from Monolithic Power Systems is a 3.3V windowed watchdog timer IC designed to monitor microcontroller health in safety-critical embedded systems. It delivers programmable short/long window timing (t2–t5), power-on reset with 2.9V–3.1V threshold, and open-drain WDO output requiring external pull-up. Used in automotive engine control units to prevent MCU lockup during ECU boot or runtime faults.

For engineers reviewing the MP6411GS-33-P datasheet, MP6411GS-33-P pinout, MP6411GS-33-P application, or MP6411GS-33-P equivalent, key selection factors include VCC=3.3V operation, MODE-selectable window mode (short: 15/10 cycles; long: 1500/1000 cycles), /WD_DIS disable function, and SOIC8 package compatibility with industrial PCB layouts.

Technical Context

The MP6411GS-33-P implements a state-machine-based windowed watchdog with three core operational states: sync signal monitoring (t1 = 450 cycles), window open/close (mode-dependent t2–t5), and reset pulse generation (t6 = 4 cycles). Its timing is resistor-programmable via TIMER pin using RTIMER = 51kΩ for nominal 880µs period.

It features dual-voltage logic thresholds: WDI/MODE//WD_DIS high = 2.1V min, low = 0.6V max; WDO operates as open-drain MOSFET output requiring external pull-up (e.g., 100kΩ); internal weak pull-ups on MODE and /WD_DIS ensure default-enable behavior when left floating.

Key Specifications

Pinout & Package

MP6411GS-33-P is housed in an industry-standard SOIC-8 package (5.0mm × 4.0mm, 1.27mm pitch) with exposed pad not present. Pin functions are validated per MPS MP6411 Rev. 1.1 datasheet Figure 7 and Package Reference diagram.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6373ESA+ and TPS3823DBVR, MP6411GS-33-P uniquely provides resistor-programmable windowed timing with sub-millisecond resolution, enabling precise alignment with MCU instruction cycles - critical for ISO 26262-compliant automotive software stacks.

Availability

MP6411GS-33-P is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC mainboards, medical infusion pump controllers, and railway signaling interface modules requiring stable component supply across extended product lifecycles.

Supply support for MP6411GS-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 MP6411 belongs to MPS's system-supervision product line, engineered specifically for functional-safety-critical embedded systems where deterministic watchdog behavior and robust POR performance are mandatory.

FAQ

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

MP6411GS-33-P asserts WDO low when VCC rises above 1V, then holds low for t0 = 10 cycles (≈8.8ms with RTIMER = 51kΩ) after VCC reaches 90% of 3.3V. The rising POR threshold is 2.9–3.1V; falling threshold is 2.8–3.0V, providing 100mV hysteresis to prevent chatter during brown-out.

How does the /WD_DIS pin function in practice?

/WD_DIS is an active-low watchdog disable input with internal weak pull-up. When left unconnected, it defaults to high and enables normal watchdog operation. Pulling it low disables all timing functions except POR - WDO remains high regardless of WDI activity, allowing safe MCU firmware updates without unintended resets.

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

Yes, but only for logic interfacing: WDI, MODE, and /WD_DIS accept 5V-tolerant inputs (min high = 2.1V), and WDO open-drain output can be pulled up to 5V. However, VCC must remain at 3.3V ±10%; applying 5V to VCC will damage the device.

What happens if the MCU fails to toggle WDI within the window?

If WDI_OK is absent during the open window (t3 or t5), the watchdog transitions to close window state and waits for t2 or t4. If no valid WDI_OK occurs before that close window expires, WDO is pulled low for t6 = 4 cycles (≈3.5ms), then the device re-enters sync monitoring state - repeating the sequence until valid WDI_OK is received.

Is RTIMER value fixed or adjustable for timing calibration?

RTIMER is fully adjustable: T(µs) = 15.75 × RTIMER(kΩ) + 73.5. For example, RTIMER = 43.2kΩ yields T = 755µs; RTIMER = 59.0kΩ yields T = 999µs. This linear relationship allows precise matching to MCU instruction cycle counts or communication frame intervals.

Does MP6411GS-33-P support watchdog disable during MCU sleep modes?

Yes - pulling /WD_DIS low disables the watchdog while preserving POR functionality. This allows the MCU to enter deep-sleep without generating spurious resets, then re-enable the watchdog upon wake-up by releasing /WD_DIS to its internal pull-up state.

What is the maximum allowable TIMER pin voltage?

The TIMER pin is rated for -0.3V to +6V per Absolute Maximum Ratings. During normal operation with RTIMER = 51kΩ, the pin voltage remains near 0.3V (per Electrical Characteristics table), well within safe margin. No external clamping is required.