AD9280

–6–

DEFINITIONS OF SPECIFICATIONS

Integral Nonlinearity (INL)

Integral nonlinearity refers to the deviation of each individual

code from a line drawn from “zero” through “full scale.” The

point used as “zero” occurs 1/2 LSB before the first code transi-

tion. “Full scale” is defined as a level 1 1/2 LSB beyond the last

code transition. The deviation is measured from the center of

each particular code to the true straight line.

Differential Nonlinearity (DNL, No Missing Codes)

An ideal ADC exhibits code transitions that are exactly 1 LSB

apart. DNL is the deviation from this ideal value. It is often

specified in terms of the resolution for which no missing codes

(NMC) are guaranteed.

Typical Characterization Curves

CODE OFFSET

1.0

0.5

–1.0

0

240

32

64

96

128

160

192

224

0

–0.5

Figure 3. Typical DNL

CODE OFFSET

1.0

0.5

–1.0

0

240

32

64

96

128

160

192

224

0

–0.5

Figure 4. Typical INL

Offset Error

The first transition should occur at a level 1 LSB above “zero.”

Offset is defined as the deviation of the actual first code transi-

tion from that point.

Gain Error

The first code transition should occur for an analog value 1 LSB

above nominal negative full scale. The last transition should

occur for an analog value 1 LSB below the nominal positive full

scale. Gain error is the deviation of the actual difference be-

tween first and last code transitions and the ideal difference

between the first and last code transitions.

Pipeline Delay (Latency)

The number of clock cycles between conversion initiation and

the associated output data being made available. New output

data is provided every rising edge.

INPUT FREQUENCY – Hz

60

55

20

1.00E+05

1.00E+08

1.00E+06

1.00E+07

50

45

25

40

35

30

–0.5 AMPLITUDE

–6.0 AMPLITUDE

–20.0 AMPLITUDE

Figure 5. SNR vs. Input Frequency

60

55

20

1.00E+05

1.00E+08

1.00E+06

1.00E+07

50

45

25

40

35

30

INPUT FREQUENCY – Hz

–0.5 AMPLITUDE

–6.0 AMPLITUDE

–20.0 AMPLITUDE

Figure 6. SINAD vs. Input Frequency

Span from 0.5 V to 2.5 V, External Reference, unless otherwise noted)

REV. E