S-103T

Overview

The S-103T is a surface-mount current regulating diode (CRD) from Semitec's S series, designed to maintain a constant current flow despite voltage fluctuations. It features a rated power of 500 mW and operates within a temperature range of -40°C to +150°C. The device provides a typical pinch-off current of 10 mA at 10V, with a limiting voltage of 3.5V. It supports a maximum peak operating voltage of 50V and allows an allowable reverse current of 50mA. The component utilizes a 2-SMD flat lead package for surface mounting.

Feature Summary

• Maintains constant current across a wide voltage range from less than 1V to 100V
• Requires only a single component to replace multi-part constant current circuits
• Operates reliably under varying load resistance changes and ripple voltage conditions

Applications

• Constant current source for LED brightness stabilization
• Battery charge and discharge circuits
• Current source for proximity sensors and other sensors
• Stabilized power supply circuits

Procurement Notes

Verify the specific ordering suffix against official documentation to confirm packaging type and taping specifications. Confirm that the requested quantity aligns with the manufacturer's standard reel quantities for surface mount devices. Ensure compliance with RoHS3 standards and check for any specific handling requirements related to the SMD package during assembly.

Selection Notes

Select the S-103T when a stable 10 mA current is required in applications with significant voltage variations. Consider the 500 mW power rating and the -40°C to +150°C operating temperature range for environmental suitability. Evaluate if the 50V maximum voltage limit meets the circuit requirements compared to higher voltage variants in the S series.

Part Context

The S-103T belongs to Semitec's S series of current regulating diodes, which are surface-mount versions of their axial E series components. This series is engineered for compact designs where space is limited but consistent current regulation is critical. The S series shares functional characteristics with the E series but differs in physical packaging and thermal performance ratings.

Replacement Considerations

The E-103 is the axial leaded equivalent of the S-103T. When replacing, account for differences in mounting style, power rating (300 mW for E series vs 500 mW for S series), and operating temperature range (-30°C to +150°C for E series). Verify that the PCB layout accommodates the change from SMD to through-hole or vice versa.