THS6072 Datasheet, PDF (12/24 Pages) Texas Instruments – LOW-POWER ADSL DIFFERENTIAL RECEIVER

THS6072
LOW-POWER ADSL DIFFERENTIAL RECEIVER
SLOS290A – FEBRUARY 2000 – REVISED APRIL 2000
APPLICATION INFORMATION
theory of operation
The THS6072 is a high-speed, operational amplifier configured in a voltage feedback architecture. It is built
using a 30-V, dielectrically isolated, complementary bipolar process with NPN and PNP transistors possessing
f_Ts of several GHz. This results in an exceptionally high performance amplifier that has a wide bandwidth, high
slew rate, fast settling time, and low distortion. A simplified schematic is shown in Figure 39.
(7) VCC +
IN – (2)
(6) OUT
IN + (3)
(4) VCC –
NULL (1)
NULL (8)
Figure 39. THS6072 Simplified Schematic
noise calculations and noise figure
Noise can cause errors on very small signals. This is especially true when amplifying small signals, where
signal-to-noise ratio (SNR) is very important. The noise model for the THS6072 is shown in Figure 40. This
model includes all of the noise sources as follows:
• e_n = Amplifier internal voltage noise (nV/√Hz)
• IN+ = Noninverting current noise (pA/√Hz)
• IN– = Inverting current noise (pA/√Hz)
• e_Rx = Thermal voltage noise associated with each resistor (e_Rx = 4 kTR_x )
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