Pre-biased NPN for space-constrained digital outputs
The Infineon BCR503E6327HTSA1 is an NPN pre-biased transistor in a PG-SOT23 package, integrating two 2.2 kOhm resistors — one in series with the base, one between base and emitter. This internal bias network eliminates the two external resistors normally required for a saturated switch, saving board area and reducing component count in digital output stages, relay drivers, and logic-level interface circuits. With a collector-emitter breakdown voltage of 50 V and a continuous collector current rating of 500 mA, it suits low-side switching of inductive loads such as small relays, solenoids, and indicator lamps in 12 V and 24 V industrial control systems. The 100 MHz transition frequency is adequate for PWM dimming and low-speed switching up to several hundred kilohertz.
Last Buy — plan the final order
The BCR503E6327HTSA1 carries a Last Buy lifecycle status. This means Infineon has announced a final production window; after that date the part will no longer be manufactured. Procurement should confirm the last-time-buy deadline with their Infineon contact or distributor and place a lifetime buy to cover forecasted demand. Once the LTB window closes, supply will shift to the independent surplus channel, where pricing and availability become less predictable. For new designs, consider evaluating a current-production pre-biased transistor from the same BCR5xx family with similar resistor ratios and package footprint. The base product number BCR503 indicates the 2.2 kOhm / 2.2 kOhm bias configuration; other members of the family offer different resistor values for varying drive requirements.
Sourcing for sustainment programs
Because the BCR503E6327HTSA1 is in Last Buy, it is not available through the standard new-production channel. We source this part through our independent distribution network, which includes franchised overstock, authorized-distributor excess, and verified surplus inventory. This channel is the primary option for medical, defense, and industrial sustainment programs that need to bridge the gap between the LTB and a qualified replacement.