THS4271-EP Datasheet, PDF (24/44 Pages) Texas Instruments – LOW NOISE, HIGH SLEW RATE, UNITY GAIN STABLE VOLTAGE FEEDBACK AMPLIFIER

THS4271-EP
SGLS270C – DECEMBER 2004 – REVISED APRIL 2010
3.3 V 3.3 V
100 Ω
100 Ω
DAC5675
14-Bit,
400 MSps
249 Ω
124 Ω
249 Ω
249 Ω
+5 V
_
THS4271
+
-5 V
249 Ω
49.9 Ω
RF
LO
Figure 81. Differential to Single-Ended
Conversion of a High-Speed DAC Output
For cases where a differential signaling path is
desirable, a pair of THS4271 amplifiers can be used
as output buffers. The circuit depicts differential drive
into a mixer IF inputs, coupled with additional signal
gain and filtering.
3.3 V 3.3 V
100 Ω
100 Ω
1 nF
THS4271
+
_
C_F
DAC5675
14-Bit,
400 MSps
249 Ω
100 Ω
249 Ω
249 Ω
249 Ω
1 nF
C_F
_
1 nF
IF+
49.9 Ω
49.9 Ω
RF_(out)
IF-
1 nF
+
THS4271
Figure 82. Differential Mixer Drive Circuit
Using the DAC5675 and the THS4271
www.ti.com
Active Filtering With the THS4271
High-frequency active filtering with the THS4271 is
achievable due to the amplifier high slew-rate, wide
bandwidth, and voltage-feedback architecture.
Several options are available for high-pass, low-pass,
bandpass, and bandstop filters of varying orders. A
simple two-pole low pass filter is presented here as
an example, with two poles at 100 MHz.
50 Ω Source
V_I
249 Ω
61.9 Ω
6.8
pF
249 Ω
5V
_
THS4271
+
−5 V
49.9 Ω
V_O
33 pF
Figure 83. A Two-Pole Active Filter With Two
Poles Between 90 MHz and 100 MHz
24
Submit Documentation Feedback
Copyright © 2004–2010, Texas Instruments Incorporated
Product Folder Link(s): THS4271-EP