HFC-S Cologne Chip AG, HFC-S Datasheet - Page 45

• Manufacturer Part Number: HFC-S
• Description: Isdn S/t HDLC Basic Rate Controller
• Manufacturer: Cologne Chip AG

7.2
Figure 10: External transmitter circuitry
Part List
R1
R2
R3, R3'
R4
R5
R6
R7
R8
C1, C1'
C3
S/T module
VDD +5 V
*)
March 1997
TX1_HI
TX2_LO
value is depending on the used S/T module
External transmitter circuitry
R1
R2
*)
2.2 k
3.0 k
18
100
5.6 k
3.3 k
3.3 k
3.3 k
10 - 33 pF (optional)
470 pF
see Table 4 on page 46
(if VDD
C1
T2
1%
1%
T1
T3
+5V R1/R1' and R2/R2' must be changed)
R3
R4
R7
R8
GND
R3´
R6
D2, D3,
D4, D5
ZD1, ZD2
T1, T1',
T2, T2'
T3
T1´
ZD2
T2´
D2
D4
C3
C1´
R5
D3
D5
1N4148 or LL4148
Z-Diode 2.7 V (e. g. BZV 55C 2V7)
BC550C, BC850C or similar
BC560C, BC860C or similar
R1´
R2´
ZD1
TX_EN
TX1_LO
TX2_HI
VDD
GND
VDD
9
8
7
S/T module
18
1
3
TX +
TX -
45 of 57
HFC-S
S/T side