MAX1028 Maxim Integrated Products, MAX1028 Datasheet - Page 20

• Manufacturer Part Number: MAX1028
• Description: (MAX1030 / MAX1028 / MAX1026) 10-Bit 300ksps ADCs with FIFO / Temp Sensor / Internal Reference
• Manufacturer: Maxim Integrated Products

Integral nonlinearity (INL) is the deviation of the values
on an actual transfer function from a straight line. This
straight line can be either a best-straight-line fit or a line
drawn between the end points of the transfer function,
once offset and gain errors have been nullified. INL for
the MAX1026/MAX1028/MAX1030 is measured using
the end-point method.
Differential nonlinearity (DNL) is the difference between
an actual step width and the ideal value of 1 LSB. A
DNL error specification of less than 1 LSB guarantees
no missing codes and a monotonic transfer function.
Aperture jitter (t
the time between the samples.
Aperture delay (t
edge of the sampling clock and the instant when an
actual sample is taken.
For a waveform perfectly reconstructed from digital
samples, signal-to-noise ratio (SNR) is the ratio of the
full-scale analog input (RMS value) to the RMS quanti-
10-Bit 300ksps ADCs with FIFO,
Temp Sensor, Internal Reference
Figure 8. Unipolar Transfer Function, Full Scale (FS) = V
20
11 . . . 111
11 . . . 110
11 . . . 101
00 . . . 011
00 . . . 010
00 . . . 001
00 . . . 000
______________________________________________________________________________________
OUTPUT CODE
(COM)
0
1
AJ
2
) is the sample-to-sample variation in
INPUT VOLTAGE (LSB)
AD
3
) is the time between the rising
Differential Nonlinearity
FULL-SCALE
TRANSITION
Signal-to-Noise Ratio
Integral Nonlinearity
Aperture Delay
Aperture Jitter
FS - 3/2 LSB
Definitions
1 LSB =
FS = V
ZS = V
FS
REF
COM
1024
V
REF
+ V
REF
COM
zation error (residual error). The ideal, theoretical mini-
mum analog-to-digital noise is caused by quantization
error only and results directly from the ADC’s resolution
(N bits):
In reality, there are other noise sources besides quanti-
zation noise, including thermal noise, reference noise,
clock jitter, etc. Therefore, SNR is calculated by taking
the ratio of the RMS signal to the RMS noise, which
includes all spectral components minus the fundamen-
tal, the first five harmonics, and the DC offset.
Signal-to-noise plus distortion (SINAD) is the ratio of the
fundamental input frequency’s RMS amplitude to the
RMS equivalent of all other ADC output signals:
Effective number of bits (ENOB) indicates the global
accuracy of an ADC at a specific input frequency and
sampling rate. An ideal ADC error consists of quantiza-
tion noise only. With an input range equal to the full-
scale range of the ADC, calculate the effective number
of bits as follows:
Figure 9. Bipolar Transfer Function, Full Scale (±FS) = ±V
*V
COM
011 . . . 111
011 . . . 110
000 . . . 010
000 . . . 001
000 . . . 000
111 . . . 111
111 . . . 110
100 . . . 000
111 . . . 101
100 . . . 001
SINAD (dB) = 20 x log (Signal
≥ V
OUTPUT CODE
REF
/ 2
ENOB = (SINAD - 1.76) / 6.02
-FS =
SNR = (6.02 x N + 1.76)dB
FS =
ZS = COM
1 LSB =
- FS
Signal-to-Noise Plus Distortion
-V
V
REF
2
2
REF
1024
V
REF
+ V
Effective Number of Bits
COM
INPUT VOLTAGE (LSB)
COM*
RMS
/ Noise
+FS - 1 LSB
RMS
REF
)
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