GS7025 Datasheet, PDF (12/13 Pages) Gennum Corporation – Serial Digital Receiver

8-3. High Speed Outputs (SDO/SDO and SCO/SCO)
SDO/SDO and SCO/SCO are current mode outputs that
require external pullups (see Figure 17). The output signal
swings are 800mV when 75Ω resistors are used. To shift the
signal levels down by approximately 0.7 volts, place a
diode between V_CC and the pullups. When the output traces
are longer than 1in, use controlled impedance traces. Place
the pullup resistors at the end of the output traces as they
terminate the trace in its characteristic impedance (75Ω).
V_CC
GS7025
SDO
SDO
SCO
SCO
75
75
75
75
V_CC
Fig. 17
TYPICAL APPLICATION CIRCUIT
V_CC
V_CC
10k
V_CC V_CC
4n7
V_{CC VCC}
44 43 42 41 40 39 38 37 36 35 34
from GS9024
see Note 1
V_CC
V_CC
75
15nH
75 10n
37.5 75 10n
V_CC
V_CC
100k
Pot
(Optional)
0.1µ
1 DDI
2 DDI
3 V_{CC_75}
4 V_CC
5 V_EE
6 _SDI
7 _SDI
8 V_CC
9 V_EE
10 CD_ADJ
11 AGC-
GS7025
TOP VIEW
V_{EE 33}
SDO 32
SDO 31
V_EE 30
SCO ²⁹
SCO ²⁸
V_EE ²⁷
nc ²⁶
nc ²⁵
270 ²⁴
nc ²³
All resistors in ohms,
all capacitors in microfarads,
unless otherwise stated.
Power supply decoupling
capacitors are not shown.
0.1µ
12 13 14 15 16 17 18 19 20 21 22
V_CC
1.8k 15n
365
(1%)
V_CC
0.1µ 0.1µ
3.3p
V_CC V_CC
4 x 75 ^{see Note 2}
To
GS9020
V_CC
NOTES
1. It is recommended that the DDI/DDI inpute are not driven when the SDI/SDI inputs are being used.
This minimizes crosstalk between the DDI/DDI and SDI/SDI inputs and maximizes performance.
2. These resistors are not needed if the internal pull-up resistors on the GS9020 are used.
12
GENNUM CORPORATION
522 - 80 - 00