HFC-S+ Cologne Chip AG, HFC-S+ Datasheet - Page 56

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

863 C
7
In order to comply to the physical requirements of ITU-T recommendation I.430 and considering the
national requirements concerning overvoltage protection and electromagnetic compatibility (EMC), the
HFC-S+ needs some additional circuitry, which are shown in the following figures.
7.1
Figure 7: External receiver circuitry
Part list
VDD
R1, R1'
R2, R2'
R3
R4
R5, R5'
R6, R6'
R7
C3, C3' are for reduction of high frequency input noise and should be located as close as possible to the
HFC-S+.
%& _V '
ADJ_LEV
LEV_R2
LEV_R1
R2
R1
S/T interface circuitry
External receiver circuitry
R2
R1
R1´
R2´
5V
1 M
1.8 M
R4
C3
C3´
33 k
100 k
3.9 k
4.7 k
4.7 k
R7
C1
R3
G N D
3.3V
680 k
1.2 M
V D D
R5
R5´
G N D
D1
D3
C1
C3, C3'
D1, D2
D3, D4
S/T module
D2
D4
V D D
R6
R6´
47 nF
22 pF
1N4148 or LL4148
1N4148 or LL4148
see Table 5 on page 59
10
11
12
S/T module
:Q^eQbi " !
Cologne
Chip
16
14
5
RX +
RX -
S/T side