1997 Nov 04 152
Philips Components
Miniature ceramic plate capacitors General data
CURRENT AND MAINTENANCE TYPES
Current ceramic plate capacitors have leads provided with
a flange. They are available in a wide variety of executions.
The flange ensures excellent solderability and component
height definition on the printed-circuit boards. These
capacitors are suitable for both hand mounting and
automatic insertion.
Ceramic plate capacitors without flanged leads are not
for design-in. They are for maintenance purposes only.
They are not available on tape.
The electrical properties of capacitors with flanged leads
are the same as the electrical properties of capacitors with
straight leads.
TC DEFINITION AND RELEVANT CODES
The variation of capacitance with temperature is
determined by:
1. Temperature coefficient of capacitance.
2. Temperature characteristic of capacitance.
The temperature coefficient of capacitance is applicable to
class 1 capacitors. They show a predictable and almost
linear change of capacitance with temperature.
This makes them suitable for temperature compensation
in resonant and tuning circuits (N150 to N1500), and in all
critical applications which require a very small capacitance
change with temperature (NP0).
The dielectric number indicates the nominal value of the
temperature coefficient of capacitance with the letters ‘P’
or ‘N’ indicating a positive or negative capacitance change
with the temperature. For example, P100 indicates a
positive temperature coefficient of 100 ×10−6/°C and
N750 indicates a negative temperature coefficient of
750 ×10−6/°C. In accordance with
“RS198”
, the P100 is
identified with the code M7G and the N750 with the
code U2J.
The temperature characteristic of capacitance is specified
by means of letters and numbers denoting the maximum
permissible capacitance change from 20 °C over a
specified temperature range. The
“EIA publication RS198”
has a similar coding system but the reference temperature
is 25 °C.
Tables 1 and 2 show the temperature characteristic of
capacitance in accordance with
“IEC 384-9”
and
“RS198”
respectively.
Table 3 shows the temperature coefficient codes in
accordance with
“RS198”
.
As an example, a capacitor with a capacitance change of
−56 to +20% in the temperature range from −55 to +85 °C
will be defined as a class 2E2 capacitor in accordance with
“IEC 384-9”
and X5U in accordance with
“RS198”
.
Also, a capacitor with a temperature change of 0 ±30 ppm
will be defined as C0G in accordance with
“RS198”
(see Table 3) and NP0 in accordance with
“IEC 384-8”
.