LOW POWER, DC-COUPLED,

6kW

R

2A

402W

C

1A

129pF

C

2

257pF

C

1B

129pF

R

1A

402W

R

1B

402W

R3A

232W

R3B

232W

50W

6kW

+12V

V

CM

V

CM

V

OUT

V

IN

1000pF

50W

R

2B

402W

1/2

OPA2889

1/2

OPA2889

OPA2889

www.ti.com ....................................................................................................................................................... SBOS373B – JUNE 2007 – REVISED AUGUST 2008

minimize the distortion introduced by the filter. In

SINGLE-TO-DIFFERENTIAL DRIVER FOR

such cases, the gain of the circuit shown on the front

≤100kHz INPUT

page of the data sheet can be increased to keep the

input to the ADS8472 large in order to keep the SNR

In systems where the input is differential (see

of the system high. Note that the gain of the system

front-page figure), the OPA2889 can be used in the

from the positive input to the output of the OPA2889

inverting configuration with an additional dc bias

in such a configuration is a function of the ac signal

applied to its positive input so as to keep the input to

gain. A resistor divider can be used to scale the

the ADS8472 within its rated operating voltage range.

output of the REF3220 or REF3240 to reduce the

The dc bias can be derived from the REF3220 or the

voltage at the dc input to OPA2889 to keep the

REF3240

reference

voltage

ICs.

The

input

voltage at the input of the converter within its rated

configuration shown on the front page of the data

operating range.

sheet is capable of delivering better than 100dB SNR

and –100dBc THD at an input frequency of 200kHz.

In case band-pass filters are used to filter the input,

care should be taken to ensure that the signal swing

at the input of the band-pass filter is small, so as to

Figure 59. Single-Supply, MFB Active Filter, 2MHz LP Butterworth

Copyright © 2007–2008, Texas Instruments Incorporated

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Product Folder Link(s): OPA2889