Datasheet

_
+
THS4211
49.9 Ω
50 Ω Source
392 Ω
3.9 pF
5 V
-5 V
33 pF
V
O
392 Ω
57.6 Ω
V
I
392 Ω
_
+
THS4211
49.9 Ω
100 Ω
392 Ω
100 Ω
+5 V
-5 V
14-Bit,
400 MSps
DAC5675
RF
LO
196 Ω
392 Ω
392 Ω
3.3 V3.3 V
392 Ω
_
+
49.9 Ω
100 Ω
100 Ω
14-Bit,
400 MSps
DAC5675
3.3 V3.3 V
C
F
1 nF
392 Ω 49.9 Ω
1 nF
1 nF
C
F
392 Ω
392 Ω
_
+
THS4211
THS4211
RF
(out)
IF+
IF-
100 Ω
1 nF
_
+
49.9 Ω
100 Ω
V
O+
V
I+
_
+
49.9 Ω
100 Ω
V
O-
787 Ω
392 Ω
392 Ω
100 Ω
V
I-
THS4211
THS4215
www.ti.com ................................................................................................................................... SLOS400E –SEPTEMBER 2002–REVISED SEPTEMBER 2009
Using the THS4211 as a DAC Output Buffer Active Filtering with the THS4211
Two example circuits are presented here showing the High-frequency active filtering with the THS4211 is
THS4211 buffering the output of a digital-to-analog achievable due to the amplifier's high slew-rate, wide
converter. The first circuit (Figure 80) performs a bandwidth, and voltage feedback architecture.
differential to single-ended conversion with the Several options are available for high-pass, low-pass,
THS4211 configured as a difference amplifier. The bandpass, and bandstop filters of varying orders. A
difference amplifier can double as the termination simple two-pole low pass filter is presented in
mechanism for the DAC outputs as well. Figure 82 as an example, with two poles at 100 MHz.
Figure 82. A Two-Pole Active Filter With
Two Poles Between 90 MHz and 100 MHz
Figure 80. Differential to Single-Ended
Conversion of a High-Speed DAC Output
A Low-Noise Receiver with the THS4211
For cases where a differential signaling path is
A combination of two THS4211 amplifiers can create
desirable, a pair of THS4211 amplifiers can be used
a high-speed, low-distortion, low-noise differential
as output buffers. The circuit in Figure 81 depicts a
receiver circuit as depicted in Figure 83. With both
differential drive into a mixer's IF inputs, coupled with
amplifiers operating in the noninverting mode of
additional signal gain and filtering.
operation, the circuit presents a high load impedance
to the source. The designer has the option of
controlling the impedance through termination
resistors if a matched termination impedance is
desired.
Figure 81. Differential Mixer Drive Circuit
Using the DAC5675 and the THS4211
Figure 83. A High Input Impedance, Low-Noise,
Differential Receiver
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