MMDT521LW-AQ

Overview

The MMDT521LW-AQ is an SMD digital NPN transistor manufactured by Diotec Semiconductor, housed in a SOT-323 surface-mount package. It integrates bias resistors to reduce component count and board space. The device supports a maximum collector voltage of 50 V and a continuous collector current of 100 mA, with a power dissipation rating of 200 mW at 25°C ambient temperature on a PCB with 3 mm² copper pads. The transition frequency is typically 250 MHz. The suffix -AQ indicates the part is currently undergoing AEC-Q101 automotive qualification. Internal resistor values are R1 = 4.7 kΩ and R2 = 4.7 kΩ.

Feature Summary

• Integrates bias resistor combinations for cost and space savings
• Designed for digital controls, switching, and signal processing applications
• Compliant with RoHS (without exemption), REACH, and Conflict Minerals regulations

Applications

• Digital controls
• Switching circuits
• Signal processing

Procurement Notes

Verify the specific manufacturing status of the -AQ suffix directly with Diotec Semiconductor before finalizing procurement plans. Confirm whether the component has completed its AEC-Q101 qualification process or remains in the qualification phase. Ensure that the standard commercial grade specifications align with the project's reliability requirements if automotive certification is not yet finalized.

Selection Notes

Select this component when a compact NPN digital transistor with integrated biasing is required for low-voltage switching tasks. The 4.7 kΩ / 4.7 kΩ resistor combination suits general-purpose logic interfacing. Verify that the 50 V collector-emitter voltage and 100 mA current limits exceed the circuit's peak operating conditions. Consider the SOT-323 footprint constraints during PCB layout design.

Part Context

This part belongs to the MMDT521DW through MMDT521ZW series of SMD digital NPN transistors from Diotec Semiconductor. The series offers various internal resistor configurations within the same SOT-323 package to accommodate different drive requirements. The MMDT521LW variant specifically features 4.7 kΩ base and emitter resistors, providing a balanced input impedance for standard digital logic applications.

Replacement Considerations

Other parts within the MMDT521 series may serve as functional substitutes if their internal resistor values match the 4.7 kΩ / 4.7 kΩ configuration. Verify pinout compatibility and electrical ratings against the target application requirements before substitution.