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Preliminary Data Sheet
INDT/R166B
INDT/R331B
Date: 2005-03-14 Revision: 0.1
Page 16 of 40
3 Electrical Specification
3.1 External Circuits
3.1.1 External Loop Filter Specification
The internal PLLs of the INDT166B/331B and the INDR166B/331B devices require an external RC loop filter (Figure 3.1).
R1
R2
C
CAPx
CAPy
Figure 3.1: External Loop Filter Circuit
It is recommended to implement the 0-Ohm resistors R1 and R2 for the transmitter as real components, because their
values may change in future versions. Table 3.1 shows the optimal values for the INDT/R166B, Table 3.2 for the
INDT/R331B. It is recommended to use SMD ceramic chip capacitors and chip resistors.
Link
Signals
Pins
Parameter
Symbol
Value Tx
(INDT166B)
Value Rx
(INDR166B)
Loop Filter Capacitor
C
1µF
1µF
Loop Filter Resistor 1
R1
0
Ω
47
Ω
PLL0
CAP1
CAP2
C11
C12
Loop Filter Resistor 2
R2
0
Ω
47
Ω
Table 3.1: External Loop Filter Specification for INDT/R166B
Link
Signals
Pins
Parameter
Symbol
Value Tx
(INDT331B)
Value Rx
(INDR331B)
Loop Filter Capacitor
C
1µF
1µF
Loop Filter Resistor 1
R1
0
Ω
47
Ω
PLL0
CAP1
CAP2
A15
B15
Loop Filter Resistor 2
R2
0
Ω
47
Ω
Loop Filter Capacitor
C
1µF
1µF
Loop Filter Resistor 1
R1
0
Ω
47
Ω
PLL1
CAP3
CAP4
A8
B8
Loop Filter Resistor 2
R2
0
Ω
47
Ω
Table 3.2: External Loop Filter Specification for INDT/R331B
3.1.2 Serial Transmission Cable Interconnect
The serial lines have to be AC-coupled through 100 nF capacitors; RF ceramic capacitors shall be used. Values for R and
L are dependent on the type of cable.
INDT
INDR
TX0+
Only INDT/R 330
TX0–
TX1+
TX1–
RX2+
RX2–
RX0+
RX0–
RX1+
RX1–
TX2+
TX2–
Decoupling capacitor
Cable termination
L
R
L
R
L
R
Downstream
Upstream
Figure 3.2: Decoupling and Cable Termination
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