THS7002EVM datasheet(15/32 Pages) TI

15 / 32 page

THS7001, THS7002

70-MHz PROGRAMMABLE-GAIN AMPLIFIERS

SLOS214B – OCTOBER 1998 – REVISED AUGUST 1999

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

theory of operation

Each section of the THS7001 and THS7002 consists of a pair of high speed operational amplifiers configured

in a voltage feedback architecture. They are built using a 30-V, dielectrically isolated, complementary bipolar

process with NPN and PNP transistors possessing fTs of several GHz. This results in exceptionally high

performance amplifiers that have a wide bandwidth, high slew rate, fast settling time, and low distortion. A

simplified schematic of the preamplifiers are shown in Figure 51.

IN –

IN +

OUT

VCC –

VCC +

Figure 51. Pre-Amp Simplified Schematic

noise calculations and noise figure

Noise can cause errors on very small signals. This is especially true for the preamplifiers, which typically amplify

small signals. The noise model is shown in Figure 52. 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 )

THS7002EVM Datasheet(PDF) 15 Page - Texas Instruments