AD603
EVALUATION BOARD
The evaluation board of the AD603 enables simple bench-top
experimenting to be performed with easy control of the
AD603. Built-in flexibility allows convenient configuration to
accommodate most operating configurations. Figure 48 is a
photograph of the AD603 evaluation board.
The output is also ac-coupled and includes a 453 Ω series
resistor. The gain of the AD603 is adjusted by connecting a
voltage source between the GNEG and GPOS test loops. A 0 Ω
resistor, R5, is provided, permitting ground reference of the
differential gain control inputs. For other gain configurations, a
signal generator may be connected to the test loops, or the
GNEG and/or GPOS pins may be biased. Either pin may be
driven to either polarity within the common-mode limits of
−1.2 V to +2.0 V; therefore, to invert the gain slope, simply
consider the GPOS as the reference and drive the GNEG pin
positively with respect to GPOS.
The AD603 includes built-in gain resistors selectable at the
FDBK pin. The board is shipped with the gain at minimum,
with a 0 Ω resistor installed in R3. For maximum gain, simply
remove R3. Because of the architecture of the AD603, the
bandwidth decreases by 10, but the gain range remains at 40 dB.
Intermediate gain values may be selected by installing a resistor
between the VOUT and FDBK pins.
circuit side copper patterns and silkscreen. A bill of materials is
shown in Table 5.
Figure 48. AD603 Evaluation Board
Any dual-polarity power supply capable of providing 20 mA is
all that is required, in addition to whatever test equipment the
user wishes to perform the intended tests.
Referring to the schematic in Figure 49, the input to the VGA is
single-ended, ac-coupled, and terminated in 50 Ω to accommodate
most commonly available signal generators.
V+
V–
G1
G2 GND G3
G4
C7
10µF
25V
+
+
V+
V–
V+
C8
10µF
25V
V+
GPOS
C1
0.1µF
R1
R7
C2
0.1µF
R6
1
2
VO
GNEG
C4
R5
0Ω
AD603
GPOS
GNEG
VINP
COMM
VPOS
VOUT
VNEG
FDBK
8
7
6
5
C9
C6
0.1µF
R3
0Ω
R4
453Ω
W1
00539-048
C5
0.1µF
3
4
Figure 50. Component Side Copper
VIN
W2
R2
100Ω
V–
00539-049
C3
0.1µF
Figure 49. Schematic of the AD603 Evaluation Board
Figure 51. Circuit Side Copper
Rev. H | Page 19 of 24
00539-051
00539-050
VOUT
AD [ ANALOG DEVICES ]
