ltc1744 Linear Technology Corporation, ltc1744 Datasheet - Page 16

• Manufacturer Part Number: ltc1744
• Description: 14-bit, 50msps Adc
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
LTC1744
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.
16
CLOCK
INPUT
0.1 F
ANALOG INPUT
50
U
1:4
U
ENC
ENC
LTC1744
W
V
V
DD
DD
2V BIAS
2V BIAS
Figure 7. Transformer Driven ENC/ENC
6k
6k
U
5V
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.
BIAS
TO INTERNAL
ADC CIRCUITS
1744 F07
1744f