The TAJA475K025RNJ is a 4.7 µF tantalum capacitor rated at 25 V DC, making it a fit for decoupling a 12 V or 5 V rail where the derating rule (50% of rated voltage) leaves margin: 12.5 V continuous is safe on a 25 V part.
ESR and ripple current in power circuits
With a 3.1 Ohm ESR at 100 kHz, this capacitor's ripple current capability is modest — expect a self-heating rise that limits use in high-frequency switching converters. It suits low-ripple bypass or timing applications where ESR is not the dominant loss.
In an engine bay ambient of 105 °C, the 25 V rating still provides derating headroom.