W66910 Datasheet, PDF (19/81 Pages) Winbond – TE Mode ISDN S/T-Controller with Microprocessor Interface

Data Sheet
W66910 PCI ISDN S/T-Controller
The transmitter and receiver are implemented by differential circuits to increase signal to noise ratio (SNR). The nominal
differential line pulse amplitude at 100 Ω termination is 750 mV, zero to peak. Transformers with 2:1 turn ration are needed at
transmitter and receiver for voltage level translation and DC isolation.
To meet the electrical characteristic requirements in I.430, some additional circuits are needed. At the transmitter side, the
external resistors (18 to 33 Ω) are used to adjust the output pulse amplitude and to meet the transmitter active impedance (≥ 20 Ω
) when transmitting binary zeros. At the receiver side, the 1.8 kΩ resistors protect the device inputs, while the 10 kΩ resistors
(1.8 kΩ +8.2 kΩ ) limit the peak current in impedance tests. The diode bridge is used for overvoltage protection.
18-33Ω
SX1
GND
18-33Ω
SX2
2:1
ο VDD
100 Ω
FIG.7.3 EXTERNAL TRANSMITTER CIRCUITRY
1.8kΩ
SR1
GND
1.8kΩ
SR2
8.2kΩ
2:1
ο VDD
8.2kΩ
100 Ω
FIG.7.4 EXTERNAL RECEIVER CIRCUITRY
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Publication Release Date: Feb,2001
Revision 1.0