Single Letter Temperature Coefficient for Capacitors?

Question

A certain parts supplier offers ceramic capacitors with temperature coefficients (tempcos) of single letters -- A, E, and so on -- but I cannot find any information on what these letters specify. (The example below suggests that E is equivalent to Y5U.)

By looking into datasheets of parts with these tempcos (example), they seem to be more of a tolerance over temperature instead of a tempo code such as X7R or Y5V.

Is there a specific phrase/term for which I should be searching, or does anyone have any reference material?

Answer 1

That is because Class II and Class III dielectrics have such a high tolerance that you really can't consider it as a tempco.

In X7R and Y5V the R and V are the tolerance or tempco.

With Class I dielectrics such as C0G, they are much more stable so the C0 is the tempco code and multiplier (here basically 0 ppm/°C) and G is the tolerance for tempco, in ppm/°C.

In your example, the manufacturer tolerance code E matches the U on a Y5U capacitor. And the V of Y5V is actually slightly better than manufacturer tolerance code F.