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CERAMIC RESONATOR PRINCIPLES - page 7 / 7

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CERAMIC RESONATOR APPLICATIONS

CHARACTERISTICS OF CERAMIC RESONATOR OSCILLATION

Supply Voltage Variation Characteristics: See Fig.1 below for an example of an actual measurement of stability for a given oscillation frequency.

The following describes the general characteristics of oscillation in the basic circuit. Contact ECS International for detailed characteristics of oscillation with specific kinds of IC’s and LSI’s.

The stability against temperature change is ±0.3 to 0.5% within a range of -20˚C to + 80˚C, although it varies slightly depending on the ceramic material. Influences of load capacitance (CL1, CL2) on the oscillation frequency is relatively high as can be calculated from the formula for fOSC. The fOSC. varies by approximately ± 0.1% because of the capacitance deviation of ± 0.1% in the working voltage range. The fOSC. also varies with the characteristics of the IC.

Oscillation Level: Below are examples of actual measurements of the oscillation level against temperature, supply voltage, and load capacitance (CL1, CL2). The oscillating level is required to be stable over a wide temperature range, and temperature characteristics be as flat as possible. This change is linear with supply voltage unless the IC has an internal constant voltage power source.

+0.5

V

DD

= +5V

+0.1

V

DD

C

L1

+0.5

= +5V = 30pF

Drift (%)

0

OSC

f

  • -

    0.5

max.

  • -

    40

min.

  • 0

    40

Temperature (˚C)

80

max. min.

120

Drift (%)

0

OSC

f

  • -

    0.1

2

5 Supply Voltage (V)

8

Drift (%)

0

OSC

f

  • -

    0.5

1

2

4

C L 1 / C L 2 ( p F )

(a) Temperature Characteristics

(b) Supply Voltage Characteristics

(c) C

L2

Characteristics

+0.5

V

DD

= +5V

V

DD

C

L2

+0.5

= +5V = 30pF

Drift (%)

OSC

f

0

1

2

C L 4 2 / C L 1 ( p F )

Drift (%)

OSC

f

0

10

20

40

C 100 L ( p F )

  • -

    0.5

(d) C

L1

Characteristics

Figure 1) Examples of an Actual Measurement of Stability for a given Oscillation Frequency

  • -

    0.5

    • (e)

      CL Characteristics (CL1 = CL2)

Oscillating Level (V)

V

1H

V

2H

+6

+5

+4

+3

+2

V

DD

= +5V

+1

  • -

    40

0

  • -

    1

0

Temperature (˚C)

40

80

120

V

2L

V

IL

Oscillating Level (V)

+8

+7

+6

+5

+4

+3

+2

V

1H

V

2H

Oscillating Level (V)

V

1H

V

2H

+6

+5

+4

+3

+2

V

DD

C

L1

= +5V = 30pF

+1

1

2

4

V

2L

0

  • -

    1

C L 1 / C L 2 ( p F )

(a) Temperature Characteristics

V

DD

C

L2

+6

+5

= +5V = 30pF

V

2H

+1

0

  • -

    1

2

Supply Voltage (V) 5

V

2L

V

1L

8

(b) Supply Voltage Characteristics

+6

+5

(c) C

L2

V

Characteristics

1L

V

1H

V

2H

V

DD

= +5V

Oscillating Level (V)

+4

+3

+2

+1

V

V

1H

1L

Oscillating Level (V)

+4

+3

+2

1

2

4

+1

0

  • -

    1

(d) C

L1

V

2L

C L 2 / C L 1 ( p F )

Characteristics

Figure 2) Examples of an Actual Measurement of Output Levels

0

  • -

    1

(c) C

L2 Characteristics

(CL1

= CL2)

10

C L ( p F )

20

40

V

2L

V

1L

100

ECS, INC. INTERNATIONAL 1105 S. RIDGEVIEW, OLATHE, KS 66062 • 913-782-7787 • 800-237-1041 • FAX 913-782-6991 • WWW.ECSXTAL.COM

TECHNICAL REFERENCE

94

TECHNICAL REFERENCE

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