TCs are electrolytic capacitors that use tantalum as the anode material and passivated tantalum pentoxide as the dielectric. The advantages include greater capacitance per unit area and stabler voltage and temperature characteristics than large capacitance ceramic capacitors.
Aluminum Electrolytic Capacitor
Multilayer Ceramic Capacitor
4 to 400V
6.3 to 250V
2.5 to 50V
50 to 1600V
47 to 10000µF
0.001 to 100µF
0.47 to 1000µF
0.001 to 10µF
Wide array of breakdown voltages and capacitances
Good high frequency characteristics No polarity
Small package, Large, stable capacitance
High breakdown level No polarity
Electrolyte leakage limits life Large package size There is polarity
Capacitance varies depending on voltage and temperature Cracking/chipping possible
The cathode terminal material differs between the two. Standard TCs use manganese dioxide (MnO2) while conductive polymer types (i.e. ROHM's TCO/TCTO series) feature an organic substance, which is less combustible and provides much lower ESR (Equivalent Series Resistance) characteristics (typically 1/10th). This makes them ideal for high frequency and large current applications.
An open-function TC is specially constructed using a thermally sensitive wire to connect the die to the frame that acts like a fuse to prevent smoking and possible flames from being generated due to excessive heat caused by overcurrent.
The melted wire results in an open circuit within the capacitor.
The terminals of ROHM’s bottom-surface electrode TCs (TCT/TCTO series) protrude slightly from the edge of the package – unlike competitor products – making it possible to form a good fillet, resulting in superior solderability and junction reliability.
Yes, ROHM's TCs must be derated at temperatures exceeding 85ºC (see graph below). Since the voltage supplied to the TC can take many forms and include transients (and possible overshooting), enough margin must be designed in. Many TC manufacturers are recommending using the TCs at 50% of the rated voltage.