ltc2203 Linear Technology Corporation, ltc2203 Datasheet - Page 24

• Manufacturer Part Number: ltc2203
• Description: 16-bit, 25msps Adc
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
LTC2203/LTC2202
Digital Output Randomizer
Interference from the ADC digital outputs is sometimes
unavoidable. Interference from the digital outputs may be
from capacitive or inductive coupling or coupling through
the ground plane. Even a tiny coupling factor can result in
discernible unwanted tones in the ADC output spectrum.
By randomizing the digital output before it is transmitted
off chip, these unwanted tones can be randomized, trading
a slight increase in the noise fl oor for a large reduction in
unwanted tone amplitude.
24
U
U
RAND = HIGH,
Figure 10. Functional Equivalent of Digital Output Randomizer
SCRAMBLE
ENABLED
W
D0
RAND
LTC2203/02
U
CLKOUT
D15
D14
D2
D1
OF
The digital output is “Randomized” by applying an exclu-
sive-OR logic operation between the LSB and all other data
output bits. To decode, the reverse operation is applied;
that is, an exclusive-OR operation is applied between the
LSB and all other bits. The LSB, OF and CLKOUT output
are not affected. The output Randomizer function is active
when the RAND pin is high.
•
•
•
22032 F11
CLKOUT
OF
D15/D0
D14/D0
D2/D0
D1/D0
D0
22032fb