SA9105E

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The formula for calculating the Output Frequency (f) is given below:

f = 11.16 * FOUTX *

FOSC

*

(I

3.58MHz

3 * I

R

2

Where FOUTX

= Nominal rated frequency (4Hz, 290Hz or 1160Hz)

FOSC

= Oscillator frequency (2MHz ...... 4MHz)

I

= Input currents for current inputs (16µA at rated)

I

= Input currents for voltage inputs (14µA at rated)

I

R

= Reference current (typically 50µA)

XTAL is a colour burst TV crystal (f = 3.5795 MHz) for the oscillator. The oscillator

frequency is divided down to 1.7897 MHz on-chip, to supply the digital circuitry and the

A/D converters.

Figure 1: Application Circuit for Three Phase Power/Energy Measurement.

SA9105A

DIP-40

IC-1

10

2.5V

VI3N

0V

2.5V

DR-00233

C12

XTAL

19

18

20

17

R13

C7

C8

16

15

14

13

12

11

FROM CTs

VI2P

VI1N

VI1P

VI2N

VI3P

N

R20

R19

R18

0V

MAINS VOLTAGES

LINE 3

LINE 2

LINE 1

4

C6

R9

R10

R11

R12

R8

9

5

6

8

7

C5

3

1

2

C4

R3

R2

R1

R3A

R2A

R1A

C14

31

R14

P14

0V

C11

21

22

23

24

28

26

25

29

27

30

0V

0V

FOUT3

FOUT2

FOUT1

C13

5V

P6

0V

P5

0V

R17

R16

R15

37

C10

36

35

33

34

32

C9

39

38

40

R6

C3

+

C1

+

C2

+

R7

R5

R4

R21

2.5V

5V