1 µF, 20 V, 9 Ohm ESR — the decoupling budget
The TAJA105M020S: Rated 1 µF at 20 V with ±20% tolerance and a 9 Ohm ESR. The 9 Ohm ESR is the key thermal and ripple parameter: at the self-resonant frequency, the capacitor's impedance is dominated by this resistance, which sets the I²R heating for AC ripple currents. For a 20 V rail, the 1 µF value provides local decoupling for moderate-speed digital loads — the 9 Ohm ESR limits the ripple current to roughly 220 mA RMS before self-heating exceeds the datasheet's dissipation factor.
1206 case, -55 to +125 °C — board fit and environment
1206 (3216 Metric) footprint, size code A, seated height 1.80 mm max. The molded case provides mechanical protection and standard reflow soldering compatibility.