AD8327-EVAL Analog Devices Inc, AD8327-EVAL Datasheet - Page 9

• Manufacturer Part Number: AD8327-EVAL
• Description: BOARD EVAL FOR AD8327
• Manufacturer: Analog Devices Inc
• Type: Video Processorr

Specifications of AD8327-EVAL

• Rohs Status: RoHS non-compliant
• Contents: Evaluation Board
• For Use With/related Products: AD8327
• Lead Free Status / RoHS Status: Not Compliant

Single-Ended Inverting Input
When operating the AD8327 in a single-ended input mode V
and V
AD8327 evaluation boards, this termination method requires
the removal of R13–R16 and R20, as well as the addition of a 0 Ω
jumper at R17. Table II shows the correct values for R11 and R12
for some common input configurations. Other input imped-
ance configurations may be accommodated using the equations
in Figure 5. The inverting and noninverting inputs of the AD8327
must be balanced for all input configurations
Differential Input from Single-Ended Source
The default configuration of the evaluation board implements a
differential signal drive from a single-ended signal source. A
TOKO 1:1 transformer is included on the board for this purpose
(T3). Enabling the evaluation board for single to differential input
conversion requires R11–R12 and R16–R17 to be removed, and
0 Ω jumpers must be installed on the placeholders for R14, R15,
and R20. Table II provides typical R13 values for common
input configurations. Other input impedances may be calculated
using the equation in Figure 6. Refer to Figure 10 for evaluation
board schematic. To utilize the transformer for converting a single-
ended source into a differential signal, the input signal must
be applied to V
IN–
should be terminated as illustrated in Figure 5. On the
V
CC
Z
IN+
SDATA
SLEEP
IN
TXEN
ENB
CLK
R12 =
.
Z
800
IN
R12
800
– Z
R11
10 F
IN
100pF
0.1 F
0.1 F
R11 =
Z
R12 + Z
–
+
IN
AD8327
R12
IN
10
TO DIPLEXER Z
1
2
3
4
5
6
7
8
9
SDATA
CLK
TXEN
GND
GND
GND
V
V
CXR
V
CC
CC
OUT
0.1 F
AD8327
IN
IN+
= 75
SLEEP
GND
GND
ENB
BYP
V
V
V
V
V
IN–
CC
CC
CC
IN+
Differential Signal Source
The AD8327 evaluation board is also capable of accepting a
differential input signal. Remove R11–R12, R14–R15, and R20,
and place 0 Ω jumpers for R16–R17. See Table II for common
values of R13, or calculate other input configurations using the
equation in Figure 7.
Output Bias, Impedance, and Termination
The output of the AD8327 has a dc bias level of approximately
V
the load. The output impedance of the AD8327 is internally
maintained at 75 Ω, regardless of whether the amplifier is in
transmit enable or transmit disable mode. This eliminates the
need for external back termination resistors. If the output signal
is being evaluated using standard 50 Ω test equipment, a mini-
mum loss 75 Ω to 50 Ω pad must be used to provide the test
circuit with the proper impedance match.
CC
20
19
18
17
16
15
14
13
12
11
/2; therefore, it should be ac-coupled before being applied to
Z
IN
Z
IN
V
V
V
IN
0.1 F
0.1 F
0.1 F
0.1 F
IN
IN
+
+
–
0.1 F
0.1 F
R13 =
165
R13 =
1600
Z
IN
R13
R13
Z
1600
1600
– Z
IN
IN
1600
– Z
Z
IN
IN
V
V
AD8327
= 150
IN–
IN+
AD8327
AD8327