aplicaciones del mc10116

EUROQUARTZ LIMITED Blacknell Lane CREWKERNE Somerset UK TA18 7HETel: +44 (0)1460 230000 Fax: +44 (0)1460 230001 [email protected] www.euroquartz.co.uk

EURO QUARTZ APPLICATION NOTESOscillator Circuits

IC-Compatible Oscillator Circuit

In this circuit, resistors R1 and R2 temperature-stabilise the NANDgates, and ensure that the gates are in a linear region for start-up.Capacitor C1 is a DC block and must have <0.1Ω impedance at theoperating frequency. The crystal runs in series mode, so it isimportant that its series resistance is low. AT-cut crystals in the range1MHz to 10MHz work well, giving a duty cycle of nearly 50%, withchip-limited rise times. The circuit starts well from 0° to 70°C.

Schmitt Trigger Crystal Oscillator

A Schmitt trigger provides good squaring of the output, andsometimes eliminates the need for an extra output stage. To preventspurious oscillation ensure C2 = 1/1x104 (frequency is in Hz.)

Low-Noise Crystal Oscillator

This oscillator delivers an output of high spectral purity withoutdegrading stability. In addition to determining the oscillatorfrequency, the crystal is also used as a low-pass filter for theunwanted harmonics and as a bandpass filter for the sideband noise.The noise bandwidth is less than 100Hz. All higher harmonics aresuppressed -60dB down for the third harmonic of the 4MHzfundamental oscillator frequency.

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560560R1 R2

0.01

Xtal 2 ~ 10MHz

1

2

On/offControl

IC-Compatible Oscillator Circuit

Ca

2.2k

2N918 10k

10k2.2n

390p

0.001u12V

200mV/22

2.2n22

4MHz

100

Low-Noise Crystal Oscillator

2k

1.5k 1.5kC20.1

2k 7414

Output

Schmitt Trigger Crystal Oscillator

L2

0.01

0.01

4.7k

4.7k

C2Xc=100

L1 XL=100

C1

330

2N918C3

OutputSine Wave

0 Volts

+5 to =12VDC

Overtone Oscillator 50MHz ~ 100MHz

Overtone Oscillator 50MHz ~ 100MHz

In this circuit the crystal is AT-cut and operates in overtone mode. L1and C2 are tuned to the operating frequency, while L2 and the shuntcapacitance of the crystal should resonate at the oscillator outputfrequency. (For example, L2 is approximately 0.5µH at 90MHz. This isnecessary to tune out the crystal C0.) C3 is adjusted to match theoscillator output.

ICM7209

6~36p 20p

10MHz

+5V

Disable

O/P 1

O/P 2(f/8)

10MHz

1.25MHz

Precision Clock Generator

Precision Clock Generator

The CMOS IC directly drives 5 TTL loads from either of two bufferedoutputs. The device operates to 10MHz and is bipolar, MOS andCMOS compatible.


EURO QUARTZ APPLICATION NOTES

Fundamental Frequency Crystal Oscillator

For frequencies below 20MHz, a fundamental frequency crystal canbe used and the resonant tank is no longer required. Also at thislower frequency range the typical MECL 10,000 propagation delay of2ns becomes small compared to the period of oscillation, and it isnecessary to use a non-inverting output. Therefore the MC10116oscillator section functions simply as an amplifier. The 1.0kΩ resistorbiases the line receiver near Vss and the 0.1µF capacitor is a filtercapacitor for the Vbb supply. The capacitor, in series with the crystal,provides for minor frequency adjustments. The second section of theMC10116 is connected as a Schmitt-trigger circuit, ensuring goodMECL edges from a slow, less than 20MHz input signal. The thirdstage of the MC10116 is used as a buffer and to give complementaryoutputs from the crystal oscillator circuit. The circuit has a maximumoperating frequency of approximately 20MHz and a minimum ofapproximately 1MHz. Use a fundamental mode crystal.

Fundamental Frequency Crystal Oscillator

2~60pF

IC = MC10116

Rp

Rp

Rp

Rp

Rp

Out

Out

1.0k

Vee

Vbb inMC10116

510 5102

3

4

5

6

7

9

10

12

13

14

15

0.1uFRp = 510 to Vee or 50 to VttW W

510

R1 R2Output

510

C1 C247pF 47pF

G1 G2 G3 G4

Easy Start-up Crystal Oscillator

Easy Start-up Crystal Oscillator

This is a low-cost, crystal-controlled oscillator using one TTL gate.Start-up is ensured by the connection of NAND gates G1, G2 and G3into an unstable logic configuration and the high loop gain of thethree inverters. Select the values of R1, R2, C1 and C2 so theoscillator operates at a frequency 70% to 90% higher than requiredwith the crystal disconnected. For 1MHz to 2MHz operation a low-power 54L00 IC is recommended; for 2MHz to 6MHz, a standard5400 type, and for 6MHz to 50MHz a 54H00 or 54S00.

Output

C1 C2

22M 22k

22p 40p

IC = NOR 4001R1

R2

CMOS Crystal Oscillator

CMOS Crystal Oscillator

This circuit has a frequency range of 0.5MHz to 2.0MHz. Thefrequency can be adjusted to a precise value with trimmer capacitorC2. The second NOR gate serves as an output buffer.

Temperature-Compensated Crystal Oscillator

Temperature-Compensated Crystal Oscillator

For a 5MHz AT-cut crystal, C = 3pF to 8pF (fine frequency trimmer)C2 = 4pF to 24pF N500 (temperature compensating) C3 = 8pF to48pF N1500 (temperature compensating) and C4 = 120pF silvermica.

The different negative-coefficient capacitors are blended to producethe desired change in capacitance to counteract or compensate forthe decrease in frequency of the ‘normal’ AT-cut characteristics ofthe crystal.

10k0.05

C3C2C1

10k C4

470 33k470

680

+5VDC

Output01

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Overtone Crystal Oscillator


The crystal in this circuit is connected directly between the base andground of the transistor. Capacitor C1 is used to improve thefeedback due to the internal capacitances of the transistor. Thiscapacitor should be mounted as close as possible to the case of thetransistor. The LC tank circuit in the collector of the transistor istuned to the overtone frequency of the crystal. The emitter resistorcapacitor must have a capacitive reactance of approximately 90Ω atthe frequency of operation. The tap on inductor L1 is used to matchthe impedance of the transistor collector. Usually, the placement ofthis tap is approximately one third from the cold end of the coil. Theplacement of the trap is a trade-off between stability and maximumpower output. The output signal is taken from a link coupling coil, L2and operates by transformer action.

L2 Output

+12VDCC4.01u

L1

C310p

C1 5p

R1120C2

VXO Crystal Oscillator

VXO Crystal Oscillator

This circuit provides a stable VXO using 6MHz or 8MHz crystals.Frequency pulling on either side of series resonance is achieved byuse of the capacitor and inductor.

2k7

2.5mH1k

0.01

0.01

3900.0124k

390k16-29mH 100

100



This design gives high reliability over a wide temperature range anduses fifth and seventh overtone crystals. The inductor in parallel withthe crystal causes anti-resonance of the crystal C0 to minimizeloading. This is a common technique with overtone crystals.

1000

12V

560

1.5uH

1000

10k

1.5k

FerriteBead 120 4.3

33

0.47u

81 x 0.25mm dia

22k

1-10180

5.1

4.7

Rf out

Voltage-Controlled Crystal Oscillator

Voltage-Controlled Crystal Oscillator

A voltage-variable capacitance tuning diode is placed in series withthe crystal feedback path. Changing the voltage on Vr varies thetuning diode capacitance and tunes the oscillator. The 510kΩresistor, R1, establishes a reference voltage from the feedback loopand 0.1µF cap. C2 provides AC coupling to the tuning diode. Thecircuit operates over a tuning range of 0 to 25V. It is possible tochange the tuning range from 0 to 25V by reversing the tuning diodeD1.Centre frequency is set with the 2-60pF trimmer capacitor. Thetable above shows measured deviation for several tested crystals.

Rp

Vbb inMC10116

100k

R2

0.1uF Xc<10

2-60pF MV2108

510 510

Rp

Rp RpRp

IC=MC10116

510kR1

1.0k

0.1uFRp = 510 to Vee or 50 to VttW W

Out

Out

Vr

2

3

4

5

6

7

9

10

12

13

14

15

11

Nominal Frequency DeviationMHz +ppm -ppm

1.000 57.0 48.0 1.8432 95.5 80.3 10.000 197.4 202.8 15.000 325.4 322.9

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This circuit uses an adjustable resonant tank circuit to ensureoperation at the desired crystal overtone. C1 and L1 form theresonant tank circuit, which, with the values specified as a resonantfrequency, are adjustable from approximately 50MHz to 100MHz.Overtone operation is accomplished by adjusting the tank circuitfrequency at or near the desired frequency. The tank circuit exhibitsa low impedance shunt to off-frequency oscillations and a highimpedance to the desired frequency, which allows feedback from theoutput. Operation in this manner guarantees that the oscillator willalways start at the correct overtone.

RpRp

C2

9~35pF

C19~35pF L1

C30.1uF

Vbbin MC10116

Rp0.001uF

2

3

4

5

6

7

9

10

12

11Vbb

Out

Out

L1 = 0.33uH for 50 ~ 100MHzL1 = 1.0uH for 20 ~ 50MHzRp = 510 to Vee or 50 to VttW W

Crystal Timebase

Crystal Timebase

An on-board oscillator and a 17 stage divider compose IC1. Byconnecting a standard 3.58MHz, television colour-burst crystal asshown, an accurate source of 60Hz squarewaves is generated at theICs output, pin 1. Those pulses are then fed to IC2, a 4024 seven-stage ripple counter. Its outputs are connected directly to differentgates in IC3, which is a dual four-input NAND gate. Dependingupon which position pulse-select switch S2 occupies, one of thosegates will provide an output/reset pulse of the selected width.

C31uF

S1Reset

R222k

1

21 sec. 0.1 sec

S2IC4a

IC4b

IC4c

IC4d

22k+Vcc

Timebaseoutput

ResetOutput

IC3a

IC3b

1314

91011

121/2 4012

1/2 4012

IC24824

+Vcc+Vcc

2

456911

7

14

543

713

12

11

1/4 4811

IC1MM5369 20M

R1

C147pF

C247pF3.58MHz

+V

6

5

+Vcc

1

2

8

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aplicaciones del mc10116

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