LTC2202(RevB) View Datasheet(PDF) - Linear Technology

Part Name

Description

MFG CO.

LTC2202
(Rev.:RevB)

16-Bit, 25Msps/10Msps ADCs

Linear Technology 

LTC2203/LTC2202

APPLICATIO S I FOR ATIO

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 floor for a large reduction in

unwanted tone amplitude.

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.

24

LTC2203/02

CLKOUT

CLKOUT

OF

OF

D15

D15/D0

D14

D14/D0

•

•

•

D2

D2/D0

D1

RAND = HIGH,

SCRAMBLE

ENABLED

RAND

D0

D1/D0

D0

22032 F11

Figure 10. Functional Equivalent of Digital Output Randomizer

22032fb

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