Datasheet
EXAMPLE ANALOG-TO-DIGITAL
V
OCM
15V
V
S
R
S
R
G
R
F
R
F
+
R
T
+
R
G
C
G
0.1 mF
C
G
THS4504
V
DD
C
S
C
S
R
L
V
OD PP
=26V
R
ISO
R
ISO
-
-
FILTERING WITH FULLY DIFFERENTIAL
+
+
V
OCM
12-Bit/80MSPS
IN
IN
5 V
CM
5 V
5 V
V
S
10 mF 0.1 mF
10 mF 0.1 mF
THS4503
R
F
R
F
C
F
C
F
1 mF
R
G
R
G
0.1 mF
R
T
R
S
ADS5410
R
ISO
R
ISO
-
-
+
+
V
OCM
14-Bit/40MSPS
IN
IN
5 V
CM
5 V
V
S
10 mF
0.1 mF
THS4501
R
F
R
F
C
F
C
F
1 mF
R
G
R
G
R
T
R
S
ADS5421
0.1 Fm
R
ISO
R
ISO
-
-
V
S
R
S
R
G1
R
F1
R
F2
+
R
T
+
V
O
R
ISO
C
C
F2
C
F1
R
G2
R
ISO
-
-
FULLY DIFFERENTIAL LINE DRIVERS
THS4504
THS4505
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......................................................................................................................................................... SLOS363D – AUGUST 2002 – REVISED MAY 2008
Figure 81 illustrates the THS4500 family of devices
CONVERTER DRIVER CIRCUITS used as high speed line drivers. For line driver
applications, close attention must be paid to thermal
The THS4500 family of devices is designed to drive
design constraints due to the typically high level of
high-performance ADCs with extremely high linearity,
power dissipation.
allowing for the maximum effective number of bits at
the output of the data converter. Two representative
circuits shown below highlight single-supply operation
and split supply operation. Specific feedback resistor,
gain resistor, and feedback capacitor values are not
specified, as their values depend on the frequency of
interest. Information on calculating these values can
be found in the applications material above.
Figure 81. Fully Differential Line Driver with High
Output Swing
AMPLIFIERS
Similar to their single-ended counterparts, fully
differential amplifiers have the ability to couple
filtering functionality with voltage gain. Numerous filter
topologies can be based on fully differential
amplifiers. Several of these are outlined in A
Figure 79. Using the THS4503 with the ADS5410
Differential Circuit Collection (SLOA064 ), referenced
at the end of this data sheet. The circuit in Figure 82
depicts a simple two-pole low-pass filter applicable to
many different types of systems. The first pole is set
by the resistors and capacitors in the feedback paths,
and the second pole is set by the isolation resistors
and the capacitor across the outputs of the isolation
resistors.
Figure 80. Using the THS4501 with the ADS5421
Figure 82. A Two-Pole, Low-Pass Filter Design
The THS4500 family of amplifiers can be used as
Using a Fully Differential Amplifier with Poles
high-frequency, high-swing differential line drivers.
Located at P1 = (2 × R
F
C
F
)
– 1
in Hz and
Their high power supply voltage rating (16.5 V
P2 = (4 × R
ISO
C)
– 1
in Hz
absolute maximum) allows operation on a single 12-V
or a single 15-V supply. The high supply voltage,
coupled with the ability to provide differential outputs
enables the ability to drive 26 V
PP
into reasonably
heavy loads (250 Ω or greater). The circuit in
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