MC1391

3

MOTOROLA ANALOG IC DEVICE DATA

Figure 3. Frequency versus Temperature

Figure 4. Frequency Drift versus Warm–Up Time

Figure 5. Mark Space Ratio

Figure 6. Representative Schematic Diagram

TA, AMBIENT TEMPERATURE (°C)

0

1020

3040

50

6070

80

Reference Frequency

= 15.750 Hz

S3 in Position 2

t, TIME (s)

0

306090

120

Reference Frequency

= 15.750Hz

POSITIVE PULSE WIDTH (

µs)

010

20

30

40

50

fO = 15,750 Hz

t = 63.5

µs

R22

Oscillator

Regulator

6

VCC

Oscillator

Timing

7

Pre–Driver

Phase Detector

Z2

R14

330

R11

3.0k

Z1

D1

D2

D3

D4

R8

2.4k

R6

3.3k

Q6

2.6k

R1

Mark–Space

8

Ratio

R17

10k 2.15

Q18

R23

2k

5

Phase

Detector

Output

Q7 Q8

R9

1.2k

Q10

Q9

470

R7

Q13

R

18

Q15

Q16

4

Sawtooth

Input

Q14

k

7.5k

R19

Q12

Q17

R20

510

R21

910

R

16

6.8k

3

Sync Input

2

Ground

Q2

Q1

Q4

Q5

R4

430

2.4k

R5

7.5k

R3

R12

820

R15

3.3k

R10

3.6k

R13

240

6.8k

R2

Q3

1

Output

7.5k

Q11

30

20

10

0

–10

–20

–30

–40

–50

–60

–70

40

30

10

0

20

4.75

4.5

4.25

3.75

3.5

3.25

3.0

2.75

4.0