200-350 WVdc
CERAMIC
TRIMMERS
TUSONIX' 538 Series described
on this page is miniaturized for today's
circuitry. All ceramic construction with
optically flat interfaces provides tuning
smothness not obtainable with com-
pression type trimmers.
The silver electrodes are intimately
bonded to the top surfaces of the base
and rotor. The terminals and other
metal parts are non-ferrous and silver-
plated to provide excellent conductivity
and trouble free soldering.
.046 DIA.
1.17
ADJUSTING SLOT
.032/0.81 WIDE X .030/.076 DEEP
.093
2.36
.046
1.17
SERIES 538
Miniature
A variety of capaciatance ranges, ter-
minations and mounting provisions make
these popular trimmers ideal for nearly
all applications.
Ordering Data
MIL C-81
Designation
MIL CV31
TUSONIX Style
538-054
MIL C-81
Designation
MIL CV32
TUSONIX Style
538-067
Dielectric
Type
Code
(See Page 2)
Capacitance
Range
(pF)
.200
5.08
.585
14.86
0.035
0.89
.125
3.18
MAX.
.375
9.53
.585
14.86
.130
3.30
INDICATES
ROTOR TERMINAL
.012
0.30
.275
6.99
STATOR
TERMINAL
Specify series 538
followed by the three
digit Terminal Variation
you select from the
chart below. Then list
the Dielectric Type
Code you select from
the table at the right
and the corresponding
Capacitance Range.
Example:
538-002 A 2.0-8 pF
CV31A080
CV31B110
CV31C100
CV31D150
CV31A180
CV32A080
CV32B110
CV32C100
CV32D150
CV32A180
538-000
CV31B250
CV31C250
CV31D350
CV31E600
CV32B250
CV32C250
CV32D350
CV32E600
A
B
A
C
D
B
A
F
D
B
C
D
F
2.0 to 8
2.5 to 11
3.0 to 10
3.0 to 10
3.0 to 15
3.5 to 14
5.5 to 18
5.0 to 25
5.5 to 25
7.0 to 25
8.0 to 25
9.0 to 35
15.0 to 60
Teminal Variation Options
002
.275
6.99
TOP & BOTTOM ADJUST
0.275
6.99
.100
2.54
004
006
.300
7.62
STATOR TERM.
.150
3.81
.040
1.02
.329
8.36
008
.200
5.08
011
.100
2.54
.275
6.98
012
014
.262
6.65
.387
9.83
.040
1.02
.363
9.22
0.109/2.77 DIA.
MOUNTING HOLES
.363
9.22
.145 / 3.68
0.109/2.77 DIA.
MOUNTING HOLES
.405
10.29
0.047/1.19 DIA.
MOUNTINGHOLES
.500
12.7
.140
3.56
.300
7.62
0.047/1.19 DIA.
MOUNTING HOLES
.533
13.53
.181
4.59
0.047/1.19 DIA.
MOUNTING HOLES
0.109/2.77 DIA.
MOUNTING HOLES
0.047/1.19 DIA.
MOUNTING HOLES
.170
4.31
017
.065
1.65
.100
2.54
022
TOP & BOTTOM ADJUST
.220
5.59
.062
1.57
.100
2.54
026
0.187
4.75
.270
6.85
037
.250
6.35
.150
3.81
.300
7.62
073
.150
3.81
074
.200
5.08
076
.140
3.55
.068/1.72
MIN I.D.
.300
7.62
.100
2.54
O.D.
0.363
9.22
.040
1.02
0.047/1.19 DIA.
MOUNTING HOLES
.194
4.93
.012
.304
.300
7.62
0.047/1.19 DIA.
MOUNTING HOLES
.486
11.89
0.109/2.77 DIA.
MOUNTING HOLES
0.047/1.19 DIA.
MOUNTING HOLES
0.047/1.19 DIA.
MOUNTING HOLES
.400
10.16
0.047/1.19 DIA.
MOUNTING HOLES
.154
3.91
.197
5.0
0.051/1.29 DIA.
MOUNTING HOLES
For dimensions
≤
0.125"/3.18mm, tolerance is ± 0.015/0.38
For dimensions
≥
0.126"/3.20mm, tolerance is ± 0.030/0.76
Specifications see page 2.
Revised 9/98
Above are shown a few of the many mechanical variations available.
For special designs tailored to your application, contact your nearest
TUSONIX Sales Office or call the factory direct at 520-744-0400
SPECIFICATION
538 Series
CAPACITANCE:
When measured at room
temperature (25°C ± 5°C) and at a fre-
quency of 0.1 to 1 megahertz, the minimum
capacitance shall not be greater than that
specified at minimum setting with a +10%
tolerance, and the maximum capacitance
shall not be less than that specified at max-
imum setting with a -10% tolerance.
"Q" FACTOR:
When measured at room
temperature (25°C ± 5°C), at a frequency
of approximately 1 mega-hertz, the capa-
citor at approximately maximum rated cap-
acitance setting shall have a "Q" value not
less than indicated for the respective style.
INSULATION RESISTANCE:
The insulation
resistance at approximately maximum capa-
citance setting shall be 10 gigaohms minimum
at room temperature of (25°C ± 5°C) when
measured at 100 volts dc in a series with a
protective resistance not exceeding 1megohm
after no more than one minute application of
the voltage.
DIELECTRIC STRENGTH:
The capacitor, set
at approximately maximum capacitance shall
withstand voltage between terminals for 1 to
5 sec. as indicated for the respective style.
(50mA maximum charging current)
TORQUE:
When measured at room tempera-
ture (25°C ± 5°C), the torque required to start
and maintain rotation of the rotor through one
full turn, shall be as indicated for the respec-
tive style.
TEMPERATURE CHARACTERISTIC:
The
temperature characteristic of capacitance shall
be within the limits shown in the following table.
The temperature characteristic shall be de-
termined by measuring the capaciance (capa-
citor shall be set at approximately 75% of the
guaranteed maximum capacitance) +25°C,
-55°C, and either +85°C or +125°C, whichever
is applicable to the respective style, at a fre-
quency of 0.1 to 1megahertz. Each measure-
ment shall be made after the capacitor has reach-
ed thermal stability.
CAPACITANCE DRIFT:
With the capacitor set at
approximately 75% of the guaranteed maximum
capacitance, the capacitance drift shall be deter-
mined as the greatest difference between any two
of three 25°C measurements, when temperature
cycled
as follows: +25°C, -55°C, +85°C or +125°C,
whichever is applicable to respective style,
+25°C. The capacitance drift shall not
exceed 0.75% or 0.5ρF, whichever is greater.
Ceramic
Trimmer Capacitors
cooling chamber and allow it to reach room
temperature. Then place in an oven at a
temperature equal to maximum operating
temperature ±3°C of the respective style.
Remove from oven and allow capacitor to
cool to room temperature. The capacitor
ACCELERATED LIFE TEST:
The cap-
shall be held at the specified minimum and
acitor, at approximately 75% of the guar-
maximum temperatures long enough to
anteed maximum capacitance, shall be
reach equilibrium, and in no case less than
tested for 250 hours at twice rated voltage,
and at a temperature equal to the maximum 15 minutes. The rate of change of temper-
ature in cooling from room temperature, or
operating temperature ±3°C for the respec-
heating above it, shall not be less than 3°C
tive style. At the end of this period the cap-
per minute. The temperature cycles shall
acitance shall not have changed more than
±5% of its value before the life test or ±0.5ρF, be followed by exposure for 96 hours to a
relative humidity of 95% at 40°C ±3°C.
whichever is greater; the insulation resist-
The capacitor shall then be removed from
ance shall be 1 gigaohm minimum and the
the humidity chamber and held at 25°C
"Q" at 1 megahertz shall be at least 40% of
±5°C with a maximum humidity of 50% for
the initial test limit.
four hours. The insulation resistance shall
be at least 1 gigaohm, the "Q" at 1MHZ is
TEMPERATURE CYCLING & HUMIDITY:
at least 40% of initial test limit and the cap-
The
capacitor, at approximately 75% of the
acitance shall not have changed by more
guaranteed maximum capacitance, shall be
than ±3% or ±0.5ρF, whichever is greater,
given a treatment consisting of 5 tempera-
from its value prior to the start of the tem-
ture cycles as follows: Cool capacitor to
-55°C ±3°C. Remove the capacitor from the perature cycling.
Dielectic
Type Code
A
B
C
D
F
PERCENT CAPACITANCE CHANGE
FROM VALUE @ 25°C
-55°C
Min.
Max.
-4.5
-1.0
-1.0
+1.5
+6.0
+2.0
+3.5
+6.5
+7.0
+16.0
+85°C
Min.
Max.
-2.5
-2.5
-4.0
-5.0
-11.0
+2.0
-0.5
-1.0
-1.5
-6.0
+125°C
Min.
Max.
-4.2
-4.2
-6.7
-8.5
-15.0
+3.4
-0.8
-1.7
-2.5
-9.0
SPECIFICATIONS FOR 538 TRIMMER CAPACITORS
Working Voltage...A,B,C: 350 WVdc @ 85°C; 200 WVdc @ 125°C
D& F: 200 WVdc @ 85°C; 100 WVdc @125°C
Dielectric Strength ............................................500 Vdc for 1-5 sec.
Operating Temperature Range................................-55°C to +125°C
Torque..................................................................................1-6 oz. in.
Marking:
All Units will be marked with TUSONIX trademark,
Capacitance range and dielectric code.
Example:
T 4-15 A
