THS6072CD datasheet(12/31 Pages) NSC

12 / 31 page

THS6072

LOW-POWER ADSL DIFFERENTIAL RECEIVER

SLOS290B – FEBRUARY 2000 – REVISED JUNE 2001

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

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

fTs 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.

IN – (2,6)

IN + (3,5)

(1,7) OUT

(4) VCC –

(7) VCC +

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 (eRx = 4 kTRx )

THS6072CD Datasheet(PDF) 12 Page - National Semiconductor (TI)