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Multirange inputs, serial 16-bit adcs – Rainbow Electronics MAX1303 User Manual

Page 27

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Differential Nonlinearity (DNL)

DNL is the difference between an actual step width and
the ideal value of 1 LSB. A DNL error specification of
greater than -1 LSB guarantees no missing codes and
a monotonic transfer function.

Transition Noise

Transition noise is the amount of noise that appears at a
code transition on the ADC transfer function. Conversions
performed with the analog input right at the code transi-
tion can result in code flickering in the LSBs.

Channel-to-Channel Isolation

Channel-to-channel isolation indicates how well each
analog input is isolated from the others. The channel-to-
channel isolation for these devices is measured by
applying a near full-scale magnitude 5kHz sine wave to
the selected analog input channel while applying an
equal magnitude sine wave of a different frequency to
all unselected channels. An FFT of the selected chan-
nel output is used to determine the ratio of the magni-
tudes of the signal applied to the unselected channels
and the 5kHz signal applied to the selected analog
input channel. This ratio is reported, in dB, as channel-
to-channel isolation.

MAX1302/MAX1303

8-/4-Channel, ±V

REF

Multirange Inputs,

Serial 16-Bit ADCs

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27

MAX1302

200

4–20mA INPUT

200

4–20mA INPUT

CH0

CH8

µC

Figure 19. 4–20mA Application

MAX1302
MAX1303

CH0

REF

µP

CH1

LOW-OFFSET

DIFFERENTIAL

AMPLIFIER

BRIDGE

Figure 20. Bridge Application