ADN2913 datasheet(32/37 Pages) AD

32 / 37 page

ADN2913

Data Sheet

Rev. A | Page 32 of 37

DC-Coupled Application

The inputs to the ADN2913 can also be dc-coupled. This can be

necessary in burst mode applications with long periods of CIDs

and where baseline wander cannot be tolerated. If the inputs to

the ADN2913 are dc-coupled, care must be taken not to violate

the input range and common-mode level requirements of the

ADN2913 (see Figure 33 and Figure 34). If dc coupling is required,

and the output levels of the transimpedance amplifier (TIA) do

not adhere to the levels shown in Figure 33 and Figure 34, level

shifting and/or attenuation must occur between the TIA outputs

and the ADN2913 inputs.

1.2V

0.9V

600mV p-p,

DIFF

600mV p-p,

DIFF

VCM = 1.05V

VCM = 0.65V

INPUT (V)

0.8V

0.5V

Figure 33. Minimum Allowed DC-Coupled Input Levels

1.2V

0.7V

1.0V p-p,

DIFF

1.0V p-p,

DIFF

VCM = 0.95V

VCM = 0.75V

INPUT (V)

1.0V

0.5V

Figure 34. Maximum Allowed DC-Coupled Input Levels

Figure 35 shows 0 dB EQ mode with 50 Ω termination resistors

floated internal to the ADN2913.

50Ω

ADN2913

VCC

TIA

NIN

TIA

Figure 35. DC-Coupled Application, 0 dB EQ Input

(Rx Termination Float Mode)

Figure 36 shows the default dc-coupled configuration when

using the 0 dB EQ input. The two terminations are connected

directly to VCC in a normal CML fashion, giving a common

mode that is set by the dc signal strength from the driving chip.

The 0 dB EQ input has a high common-mode range and can

tolerate VCM up to and including VCC.

Figure 37 shows back terminated mode. The switched current

driver is back terminated, with the two VCC supplies having the

same potential.

See the 0 DB EQ section for more information.

50Ω

VCC

ADN2913

NIN

Figure 36. DC-Coupled Application, 0 dB EQ Input (Normal Mode)

50Ω

VCC

ADN2913

NIN

Figure 37. DC-Coupled Application, 0 dB EQ Input (Back Terminated Mode)

ADN2913 датащи(PDF) 32 Page - Analog Devices

ADN2913 датащи(HTML) 32 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

датащи скачать

ссылки URL