4

9145D–AUTO–05/10

ATA5021

3.

Functional Description

3.1

Supply Voltage, Pin 6

The ATA5021 requires a stabilized supply voltage V

characteristics. An external buffer capacitor of C = 10 nF may be connected between pin 6 and

GND.

3.2

RC Oscillator, Pin 8

The clock frequency, f, can be adjusted by the components R

with

T = 0.18

× (C

(C

R

C

C

assembly. With frequency calculations of original boards, this parasitic capacitor can be omitted.

Table 3-1.

Comparison Table Clock Period Calculation versus Measurement on Test Board

R1 (k

Ω)C1 (nF)

Period “T” (µs) by

New Formula

Period “T” (µs) by

Measurement

Deviation of New

Formula versus

Measurement

10.00

0.23

4.36

4.33

–0.3%

10.00

0.47

8.20

8.30

1.8%

10.00

1.04

17.26

17.10

1.4%

10.00

4.75

74.40

74.50

1.5%

10.00

10.49

156.30

152.00

–2.2%

32.91

0.23

13.45

13.25

–0.4%

32.91

0.47

25.99

26.13

1.9%

32.91

1.04

55.57

55.00

1.2%

32.91

4.75

242.10

241.50

1.2%

32.91

10.49

509.25

505.00

1.6%

46.70

0.23

18.92

18.50

–1.2%

46.70

0.47

36.69

36.63

0.8%

46.70

1.04

78.63

78.25

1.7%

46.70

4.75

343.03

341.25

0.6%

46.70

10.49

721.70

700.00

–1.6%

68.00

0.23

27.38

26.75

–1.4%

68.00

0.47

53.22

53.25

1.4%

68.00

1.04

114.25

112.50

1.5%

68.00

4.75

498.94

497.50

1.2%

68.00

10.49

1049.85

1020.00

0.0%

81.20

0.23

32.61

31.88

–1.1%

f

1

T

---

=