MMUN2241LT1

Overview

The MMUN2241LT1 is an NPN silicon Bias Resistor Transistor (BRT) in a SOT-23 package, integrating a transistor with a monolithic bias network consisting of a series base resistor and a base-emitter resistor. It features a collector-emitter breakdown voltage of 50 Vdc and a maximum collector current of 100 mAdc. The device includes a 100 kΩ input resistor (R1) with no parallel base-emitter resistor (∞). Electrical characteristics specify a DC current gain (hFE) range of 160 to 350 at VCE=10V and IC=5mA. Collector-emitter saturation voltage is typically 0.25 Vdc at IC=10mA and IB=5mA.

Feature Summary

• Integrates a single NPN transistor with a monolithic two-resistor bias network to replace discrete components.
• Designed for low-power surface mount applications using the compact SOT-23 package.
• Eliminates external bias resistors to reduce system cost and printed circuit board space.

Applications

• Level shifting between 12 or 24 volt circuits and logic levels
• Open collector inverter configurations for signal inversion
• Unregulated current source implementations

Procurement Notes

Verify the specific ordering suffix 'LT1' corresponds to the standard tape and reel shipping configuration as documented in the manufacturer's ordering information table. Confirm that the component marking 'A8U' matches the physical device received. Ensure the Pb-Free status aligns with project requirements by checking for the 'G' suffix designation if lead-free compliance is mandatory for the assembly process.

Selection Notes

Select this component when a high-value base resistor is required to drive the NPN transistor into saturation with minimal base current. The integrated 100 kΩ resistor simplifies biasing for high-impedance control signals. Verify that the required DC current gain range of 160 to 350 meets the load switching specifications. Ensure the operating ambient temperature remains within the -55°C to +150°C junction range for reliable performance.

Part Context

This part belongs to the MMUN22xxLT1 series of NPN Bias Resistor Transistors from onsemi. The series offers various resistor combinations to suit different biasing needs while maintaining the same SOT-23 form factor. The MMUN2241LT1 is distinguished by its specific 100 kΩ series base resistor configuration, providing a unique solution for high-input-impedance switching applications compared to other members of the family.

Replacement Considerations

Direct substitutes within the same series include other MMUN22xxLT1 variants with different resistor values. Cross-manufacturer equivalents should be verified against the 50 Vdc voltage rating, 100 mA current limit, and SOT-23 pinout compatibility before implementation.