HWD481CSLASHD datasheet(9/20 Pages) ETC1

9 / 20 page

HWD483/HWD487/HWD488/HWD489:

Reduced EMI and Reflections

The HWD483 and HWD487–HWD489 are slew-rate limit-

ed, minimizing EMI and reducing reflections caused by

improperly terminated cables. Figure 12 shows the dri-

ver output waveform and its Fourier analysis of a

150kHz signal transmitted by a HWD481, HWD485,

HWD490, HWD491, or HWD1487. High-frequency har-

monics with large amplitudes are evident. Figure 13

shows the same information displayed for a HWD483,

HWD487, HWD488, or HWD489 transmitting under the

same conditions. Figure 13’s high-frequency harmonics

have much lower amplitudes, and the potential for EMI

is significantly reduced.

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

VOD

VOC

RECEIVER

OUTPUT

TEST POINT

1kΩ

VCC

CRL

15pF

CL1

CL2

RDIFF

VID

OUTPUT

UNDER TEST

500Ω

VCC

_________________________________________________________________Test Circuits

Figure 4. Driver DC Test Load

Figure 5. Receiver Timing Test Load

Figure 6. Driver/Receiver Timing Test Circuit

Figure 7. Driver Timing Test Load

HWD481C/D Datenblatt(PDF) 9 Page - List of Unclassifed Manufacturers