Molded tantalum capacitor for 25 V rails
The TAJS105K025RNJ: This is a Molded tantalum capacitor from the TAJ series, rated 1 µF at 25 V with ±10% tolerance — a standard decoupling value for 3.3 V and 5 V digital rails, with headroom for 12 V intermediate buses. The 8 Ohm ESR is a design parameter: higher ESR damps ringing in power-supply filters but also contributes self-heating under ripple current. For a 1206 case, the 25 V rating leaves margin above the rail voltage, reducing the risk of field failure from voltage surges.
1206 footprint and temperature range
The 1206 (3216 Metric) case measures 3.20 mm x 1.60 mm with a seated height of 1.20 mm.