5

Test circuits and typical characteristics

In the schematics below, CL includes fixture and instrumentation capacitance.

Figure 6. Driver differential output voltage with common-mode load

375 Ω ±1%

375 Ω ± 1%

60Ω ±1%

+

-

-7 V < VCM< 12 V

D

VL

A

B

VOD

Input generator rate is 100 kbps, 50% duty cycle, rise and fall times less than 6 ns.

Figure 7. Driver differential and common-mode output with RS-485 load

RL / 2

D

VL

A

B

VOD

RL / 2

CL

VOC

A

B

VOC(PP)

ΔVOC(SS)

STR485E

Test circuits and typical characteristics

DS13051 - Rev 3

page 11/26