S-501T

Overview

The Semitec S-501T is a surface-mount current regulating diode (CRD) designed to maintain a constant current flow despite voltage fluctuations. It operates within a wide voltage range from less than 1V to 100V and requires only a single component to establish a constant current circuit. The device features a rated power of 500mW, a maximum rated voltage of 50V for the S-822 to S-223 series, and an allowable reverse current of 50mA. It supports an operating temperature range of -40°C to +150°C with a junction temperature limit of 150°C. The typical pinch-off current at 10V is 0.50mA, with a limiting current ratio ranging from +0.15% to -0.25% per degree Celsius.

Feature Summary

• Maintains constant current output regardless of applied voltage or load resistance changes
• Simplifies circuit design by replacing multiple components with a single part
• Operates reliably across a wide temperature range suitable for harsh environments

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 to confirm the packaging format, as the 'T' designation indicates SMD reel taping. Ensure the required quantity aligns with the manufacturer's standard minimum taping quantities for surface-mount devices. Confirm compliance with RoHS directives if environmental regulations apply to the final assembly process.

Selection Notes

Select the S-501T when a precise 0.50mA constant current is required in a compact surface-mount footprint. Consider the 500mW power rating and 50V maximum voltage limits during circuit design. Evaluate thermal management requirements given the -40°C to +150°C operating range and potential self-heating effects on current stability.

Part Context

The S-501T belongs to Semitec's S Series of current regulating diodes, which are specifically engineered for surface-mount technology applications. This series complements the axial-leaded E Series, offering similar electrical characteristics but optimized for automated PCB assembly processes. The S Series provides a robust solution for modern electronics requiring reliable current regulation in space-constrained designs.

Replacement Considerations

The datasheet lists the E-501 as the corresponding axial-leaded equivalent. Verify pinout compatibility and mounting constraints when substituting between SMD and through-hole packages. Ensure that the replacement component meets the same power dissipation and voltage rating requirements for the specific application.