Le87251
2.0
Applications
Data Sheet
The Le87251 integrates two sets of high-power line driver amplifiers that can be connected for full duplex
differential line transmission. The amplifiers are designed to be used with signals up to 10 MHz with low signal
distortion. The driver can put out 20.5 dBm power level onto the telephone line and can drive 450 mA current, which
exceeds the level required when using a transformer with 1:2 ratio.
2.1
Typical Application Circuit
A typical application interface circuit (one channel) is shown in Figure 3.
TX+
VINA
+
–
R
F
R
OUT
VOUTA
C
TX
2R
G
R
F
R
OUT
TX-
VINB
VOUTB
C
TX
100
R
F
R
X1
–
RX+
+
R
X2
RX-
R
X1
R
F
R
X2
Data Receive
Figure 3 - Typical Application Interface Circuit
As shown in Figure 3 the amplifiers have identical positive gain connections with common-mode rejection. Any DC
input errors are duplicated and create common-mode rather than differential line errors.
5
Zarlink Semiconductor Inc.
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
