MMUN2211LT1

Overview

The MMUN2211LT1 is an NPN Bias Resistor Transistor (BRT) from onsemi, housed in a surface-mount SOT-23 package. It integrates a single transistor with a monolithic bias network consisting of two resistors: a series base resistor (R1) and a base-emitter resistor (R2). The device features a typical input resistance of 10 kOhms with a resistor ratio of 1. Key electrical ratings include a collector-emitter voltage (VCEO) of 50 Vdc, continuous collector current (IC) of 100 mAdc, and total power dissipation (PD) of 246 mW at 25°C. The DC current gain (hFE) ranges from 35 to 60, and the operating temperature spans from -55°C to +150°C.

Feature Summary

• Integrates a single NPN transistor with a monolithic bias network containing a series base resistor and a base-emitter resistor.
• Designed to replace discrete devices and external resistor bias networks, reducing system cost and board space.
• Housed in an SOT-23 package optimized for low-power surface mount applications.

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 component authenticity by checking the marking code 'A8A' against official datasheet specifications. Confirm the package type matches the SOT-23 (TO-236) dimensions provided in the manufacturer's documentation. Ensure compliance with RoHS requirements if applicable to the specific ordering suffix. Validate that the integrated resistor values align with design requirements before finalizing procurement.

Selection Notes

Select this component when a compact solution for switching or amplification is required without external biasing components. The fixed 10 kOhm base resistor and 1:1 ratio suit standard logic interface applications. Consider the thermal characteristics and maximum ratings to ensure operation within safe limits for the intended load conditions and ambient temperatures.

Part Context

This part belongs to the MMUN2211L series of NPN silicon surface mount transistors with built-in bias resistors. It is categorized as a digital transistor designed to simplify circuit design by eliminating individual biasing components. The series includes various variants with different resistor values, but this specific model maintains a 10 kOhm input resistance.

Replacement Considerations

Direct substitutes within the same series include MMUN2211LT1G (Pb-Free version). Other BRTs like MMUN2212LT1G offer different resistor values (22 kOhm) and should be evaluated based on specific biasing needs rather than direct pin-to-pin equivalence for identical performance.

FAQ

What are the internal resistor values for the MMUN2211LT1?

The MMUN2211LT1 contains a series base resistor (R1) and a base-emitter resistor (R2), both typically valued at 10 kOhms, resulting in a resistor ratio of 1.

What is the maximum collector-emitter voltage for this device?

The maximum collector-emitter voltage (VCEO) for the MMUN2211LT1 is rated at 50 Vdc.

How does the BRT structure benefit circuit design?

The Bias Resistor Transistor structure eliminates the need for external discrete resistors, thereby simplifying the circuit design, reducing the component count, and saving board space.