Avago Technologies ACPL-224-500E - Manual (Page 32)

AV02-4387EN 29 Avago Technologies
Description
A balanced RS-422 line driver differ-
entially drives a twisted pair line. Two
HCPL-2300s provide balanced signal
direction for this line. The thresh-
olds of the HCPL-2300 will be nearly
equal, provid ing symmetrical signal
detection level. Since the propaga-
tion delays of the two optocouplers
are similar, the pulse-width distor-
tion for this scheme will be quite low
for considerable line lengths. The
Exclusive-Or flip-flop circuit at the
optocoupler output increases CMR
protection to an extremely high
level and balances the propagation
delays. For less demanding noise
environments, only one HCPL-2300
with no EX-OR flip-flop may be used.
The maximum data rate, however,
will be somewhat lower.
Performance of Circuit
• Signaling rate: > 10 MBd at 100 m
line length
• Common mode rejection:
> 15,000 V/µs
Benefits
• Very high common­mode tran-
sient rejection
• Data transmission for up to 1 km
distance
Alternative Avago Parts
HCPL-2602/12 High CMR Line Re-
ceiver
Isolated Balanced Line Receiver - Circuit No. 1
Data Communications Applications
TYPICAL SIGNAL RATE
– BAUD
1
100M
10K
L – LINE LENGTH – METERS
10 1000 10,000
10M
1M
100K
100
BALANCED
SPLIT PHASE
BALANCED
(SINGLE
HCPL-2300
NO EX- OR FF)
10% PULSE WIDTH DISTORTION
22 AWG UNSHIELDED TWISTED
PAIR WIRE CABLE (DEARBORN
NO. 862205)
TA = 25 °C