High Reliability Dipped Mica Capacitors
Download PDFHigh reliability dipped mica capacitors are designed to meet requirements for MIL-PRF-39001. Sizes starting with CMR03 and ending with CMR08 are found in a diversity of high grade ground, airborne and space-borne devices such as computers, planes and missiles. The CMR grade capacitors have replaced the MIL-C-5 grade CM capacitors which were dropped as the military standard for dipped mica capacitors in 1970. Mil-PRF-39001 capacitors can be substituted, regardless of their failure rate designation for the inactive MIL-C -5 capacitors.
Ratings
Voltage
- D= 500 VDC working
- C= 300 VDC working
- A= 100 VDC working
- Y= 50 VDC working
Capacitance: 1pF -82,000pF
Operating Temperature Range: O= -55° to 125°C P= -55° to +150° C
Stability Characteristics: C=-200 to+200 PPM/°C E=-20 to+100 PPM/°C F= -0 to+70 PPM/°C
Capacitance Tolerance: D=±.5pF F=1% G=2% J=5%
Failure Rate Levels: M=1.0% per 1000 hrs P=.1% per 1000 hrs R=.01% per 1000 hrs Part number breakdown:
Here is an example of how the high reliability dipped micas are listed
| MIL-PRF-39001 / CMR 05 C 100 J P D M | |
|---|---|
| CMR | indicates the style |
| 05 | these 2 digits indicate the size of the capacitor |
| C | indicates the temperature coefficient in PPM/°C |
| 100 | indicates the value expressed in pico farads by a 3 digit number. The first two digits represent significant figures and the last digit specifies the number of zeros to follow. 100 indicates 10pF 101 indicates 100pF and the letter R is used to indicate a decimal point so 4.7pF is expressed as 4R7 in the part number. |
| J | indicates the capacitance tolerance in this example it is 5% |
| P | indicates the operating temperature range in this example -55 to +150°C |
| D | indicates the DC working voltage in this example 500VDC |
| M | indicates the failure rate in 1000 hours of testing in this example 1% |
| MIL-C-5 / CM05 C D 100 J P 3 | |
|---|---|
| CM | indicates the style |
| 05 | 2 digits indicate the size of the capacitor |
| C | indicates the temperature coefficient in PPM/°C |
| D | indicates the DC working voltage in this example 500VDC |
| J | indicates the capacitance tolerance in this example it is 5% |
| P | indicates the operating temperature range in this example -55 to +150°C |
| 3 | indicates the vibration grade measured in MIL-STD-202 |
Dipped mica capacitors are particularly useful when tight tolerance and capacitance stability are required. Their resistance to the effects of heat and climate influences makes them ideal for harsh environmental applications. Some of the more common applications for dipped mica capacitors are oscillator circuits, logic and transmission circuits, delay lines and pulse forming networks. The advantage in using the high reliability dipped micas is they have been tested to meet the demanding requirements needed for all mil-spec capacitors.