S-301T

Overview

The Semitec S-301T is a surface-mount current regulating diode (CRD) designed to maintain constant current flow despite voltage fluctuations. It operates within a wide voltage range from less than 1V to 100V, ensuring stable current regardless of load resistance changes or ripple voltage. The device features a rated power of 500 mW and an allowable reverse current of 50 mA. Its pinch-off current at 10V is typically 0.30 mA, with a minimum of 0.20 mA and a maximum of 0.40 mA. The limiting current ratio (I100V/Ip) is specified as 0.8, and the temperature coefficient ranges from +0.40% to -0.20% per degree Celsius.

Feature Summary

• Maintains constant current flow across a wide voltage range from less than 1V to 100V
• Provides stable current output independent of load resistance changes and ripple voltage
• Requires only a single component to accomplish constant current circuit functions

Applications

• Constant current source for LED brightness stabilization
• Battery charge and discharge circuits
• Current source for piezoelectric actuators
• Telecommunications line interface
• Stabilized power supply circuits

Procurement Notes

Verify the specific ordering suffix to confirm the packaging format, as the 'T' designation indicates SMD reel taping. Ensure that the required pinch-off current tolerance aligns with the typical 0.30 mA specification and the allowed range of 0.20 mA to 0.40 mA. Confirm that the operating environment stays within the recommended temperature range of -40°C to 150°C to maintain performance integrity.

Selection Notes

Select the S-301T when a precise constant current of approximately 0.3 mA is required in a compact surface-mount form factor. Consider the 500 mW rated power and 100 V maximum voltage rating for compatibility with the target circuit design. Evaluate the temperature coefficient characteristics if the application involves significant thermal variations, as these may impact the stability of the regulated current output over time.

Part Context

The S-301T belongs to the Semitec S series of current regulating diodes, which are surface-mount devices. This series complements the axial E series, offering similar electrical characteristics in a package suitable for automated assembly. The S series generally supports higher rated power compared to some axial counterparts, making it suitable for applications requiring robust current regulation in space-constrained designs.

Replacement Considerations

The E-301 is the axial leaded equivalent within the same product family. When substituting, verify that the physical footprint and pin configuration differences do not affect the PCB layout. Ensure that the power dissipation requirements remain within the 500 mW limit for the S-301T if replacing another surface-mount CRD.