Datasheet MAX253 (Maxim) - 9

MAX253 Transformer Driver for Isolated RS-485 Interface VIN ISOLATION 6 BARRIER 5V C1 0.1μF 5 VCC 1 1N5817 1CT
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1.3CT** 8 2 ISO 5V N.C. D1 IN OUT C3 C2 C4 0.1 MAX253 μF 22μF MAX667 22μF 4 ON / OFF SD 8 D2 SET GND SHDN 3 1N5817 FS 6 4 5 GND1 GND2 2 7 5 x 3.3kΩ 10 x PC417 *74HC04 390Ω 6 VCC GND 1 8 3 T1IN T1OUT T1 5 IN 2 4 74HC04 390Ω 7 4 T2IN T2OUT T2IN 74HC04 390Ω 15 2 T3IN T3OUT T3IN 74HC04 390Ω 16 1 T4IN T4OUT T4IN 74HC04 390Ω 22 19 T5IN T5OUT T5IN MAX205 5 X 3.3kΩ 74HC04 6 390Ω 1 9 10 R1 5 OUT R1IN R1OUT 4 2 74HC04 390Ω 6 5 R2OUT R2IN R2OUT 74HC04 390Ω 23 24 R3OUT R3IN R3OUT 74HC04 390Ω 17 18 R4OUT R4IN R4OUT 74HC04 390Ω 14 13 R5OUT R5IN R5OUT SD EN *74HC04 OR EQUIVALENT 21 20 ** SEE TABLE 2 4N25 LOWER SPEED, LOWER COST ALTERNATE OPTOCOUPLER CONFIGURATIONS (FOR DATA RATES BELOW 9.6kbps) VCC 1N5711 VCC 4N25 6 1N5711 6 3.3kΩ 4N25 390Ω 3.3kΩ 1 1 ISO TIN ISO ROUT R 5 5 OUT TIN 390 74HCO4 Ω *74HC04 2 2 ISO ISO 4 4 GND GND Figure 5. Typical RS-232 Application Circuit www.maximintegrated.com Maxim Integrated | 9