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THS1401-EP Datasheet, PDF (17/27 Pages) Texas Instruments – 14-BIT, 1/3/8 MSPS DSP COMPATIBLE ANALOG-TO-DIGITAL CONVERTERS WITH INTERNAL REFERENCE AND PGA | |||
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THS1401-EP THS1403-EP THS1408-EP
14-BIT, 1/3/8 MSPS DSP COMPATIBLE ANALOG-TO-DIGITAL CONVERTERS
WITH INTERNAL REFERENCE AND PGA
SGLS129A â JULY 2002 â REVISED NOVEMBER 2002
APPLICATION INFORMATION
driving the analog input
The THS1401/3/8 ADCs have a fully differential input. A differential input is advantageous with respect to SNR,
SFDR, and THD performance because the signal peak-to-peak level is 50% of a comparable single-ended input.
There are three basic input configurations:
D Fully differential
D Transformer coupled single-ended to differential
D Single-ended
fully differential configuration
In this configuration, the ADC converts the difference (âIN) of the two input signals on IN+ and INâ.
22 â¦
100 pF
IN+
22 â¦
100 pF
THS1401/3/8
INâ
Figure 19. Differential Input
The resistors and capacitors on the inputs decouple the driving source output from the ADC input and also serve
as first order low pass filters to attenuate out of band noise.
The input range on both inputs is 0 V to AVDD. The full-scale value is determined by the voltage reference. The
positive full-scale output is reached, if âIN equals âREF, the negative full-scale output is reached, if âIN equals
ââREF.
âIN [V]
OUTPUT
ââREF
â full scale
0
0
âREF
+ full scale
⢠POST OFFICE BOX 655303 DALLAS, TEXAS 75265
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