Transformer Driver for

Isolated RS-485 Interface

______________________________________________________________________________________

13

OUTPUT

≈ -2VIN

INPUT

MAX253

GND1

GND2

1

8

6

27

1N5817

1CT:1CT*

1N5817

D1

D2

OUTPUT

≈ 2VIN

*SEE TABLE 2

Figure 9a. Half-Wave Rectifier—Bipolar

OUTPUT

INPUT

MAX253

GND1

GND2

1

8

6

27

1CT:1CT*

D1

D2

OUTPUT

4 x 1N5817

*SEE TABLE 2

Figure 9b. Full-Wave Rectifier—Bipolar

INPUT

MAX253

GND1

GND2

1

8

6

27

1CT:1CT*

D1

D2

OUTPUT

4 x 1N5817

*SEE TABLE 2

Figure 9c. Full-Wave Rectifier—Unipolar