SN75C185

LOW-POWER MULTIPLE DRIVERS AND RECEIVERS

SLLS065F – AUGUST 1989 – REVISED JANUARY 2000

9

POST OFFICE BOX 655303

APPLICATION INFORMATION

11

12

13

14

15

16

17

18

19

20

GND

RY5

DA3

RY4

DA2

DA1

RY3

RY2

RY1

VCC

VSS

RA5

DY3

RA4

DY2

DY1

RA3

RA2

RA1

VDD

10

9

8

7

6

5

4

3

2

1

43

37

40

13

36

11

41

42

RI

DTR

CTS

SO

RTS

SI

DSR

DCD

R1

DTR

CTS

TX

RTS

RX

DSR

DCD

SN75C185

5 V

TL16C450

ACE

1

5

6

9

12 V

– 12 V

TIA/EIA-232-F

DB9S

Connector

Figure 7. Typical Connection

The SN75C185 supports data rates up to 120 kbit/s over a 3-meter cable. Laboratory experiments show that,

The 500-pF load approximates a typical 3-meter cable because the maximum RS-232 specification is 2500 pF

(or about 15 meters). Figure 8 shows the test circuit used. Temperature was varied from 0

°C to 70°C for the

experiment.

NOTES: A. The pulse generator has the following characteristics: PRR = 60 kHz (120 kbit/s), ZO = 50 Ω.

B. VCC = 5 V, VDD = 12 V, VSS = –12 V.

CL

RL

Input

Output

Pulse

Generator

(See Note A)

VSS

VCC

VDD

Figure 8. Data-Rate Test Circuit