BT53W/1/B23 – FUJITSU

The FUJITSU BT53W/1/B23 is a bipolar junction transistor (BJT) array, specifically a Darlington transistor array configuration. The “/1” likely denotes a single array within the package. Based on the “BT” prefix, this is a low-power, high-gain transistor array intended for switching or amplification applications. The “B23” suffix is a date or lot code. Given the “NOT RoHS” designation, this component contains lead or other restricted substances and is not compliant with the Restriction of Hazardous Substances Directive. This part was manufactured prior to RoHS compliance mandates. The “011849” is an internal Fujitsu traceability code. Electrical characteristics, such as VCEO, IC, hFE, and power dissipation, are not specified and must be derived from legacy Fujitsu datasheets or through direct testing. The package type is not explicitly stated but is likely a through-hole SIP or DIP package based on the era of manufacture.