LTC1744 datasheet(16/24 Pages) LINER

16 / 24 page

LTC1744

1744f

Input Range

The input range can be set based on the application. For

oversampled signal processing in which the input fre-

quency is low (<10MHz), the largest input range will

provide the best signal-to-noise performance while main-

taining excellent SFDR. For high input frequencies

(>10MHz), the 2V range will have the best SFDR perfor-

mance but the SNR will degrade by 3.5dB. See the Typical

Performance Characteristics section.

APPLICATIO S I FOR ATIO

Figure 7. Transformer Driven ENC/ENC

VDD

LTC1744

1744 F07

BIAS

VDD

ENC

ANALOG INPUT

2V BIAS

1:4

0.1

µF

CLOCK

INPUT

Ω

TO INTERNAL

ADC CIRCUITS

Driving the Encode Inputs

The noise performance of the LTC1744 can depend on the

encode signal quality as much as on the analog input. The

ENC/ENC inputs are intended to be driven differentially,

primarily for noise immunity from common mode noise

sources. Each input is biased through a 6k resistor to a 2V

bias. The bias resistors set the DC operating point for

transformer coupled drive circuits and can set the logic

threshold for single-ended drive circuits.

LTC1744 Datasheet(PDF) 16 Page - Linear Technology