MAX1226BEEE-T Maxim Integrated, MAX1226BEEE-T Datasheet - Page 20

• Manufacturer Part Number: MAX1226BEEE-T
• Description: Analog to Digital Converters - ADC
• Manufacturer: Maxim Integrated

Specifications of MAX1226BEEE-T

• Number Of Channels: 8/4
• Architecture: SAR
• Conversion Rate: 300 KSPs
• Resolution: 12 bit
• Input Type: Single-Ended/Differential
• Snr: 70 dB
• Interface Type: Serial
• Operating Supply Voltage: 4.75 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Package / Case: QSOP-16
• Maximum Power Dissipation: 667 mW
• Minimum Operating Temperature: - 40 C
• Number Of Converters: 1
• Voltage Reference: Internal 4.096 V or External

12-Bit 300ksps ADCs with FIFO,
Temp Sensor, Internal Reference
Figure 8. Unipolar Transfer Function, Full Scale (FS) = V
20
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-
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):
______________________________________________________________________________________
11 . . . 111
11 . . . 110
11 . . . 101
00 . . . 011
00 . . . 010
00 . . . 001
00 . . . 000
OUTPUT CODE
(COM)
0
SNR = (6.02 x N + 1.76)dB
1
AJ
2
) is the sample-to-sample variation in
AD
INPUT VOLTAGE (LSB)
3
) is the time between the rising
Differential Nonlinearity
FULL-SCALE
TRANSITION
Signal-to-Noise Ratio
Aperture Delay
Aperture Jitter
FS - 3/2 LSB
1 LSB =
FS = V
ZS = V
FS
REF
COM
4096
V
REF
+ V
REF
COM
Figure 9. Bipolar Transfer Function, Full Scale (±FS) = ±V
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:
*V
COM
SINAD (dB) = 20 x log (Signal
011 . . . 111
011 . . . 110
000 . . . 010
000 . . . 001
000 . . . 000
111 . . . 111
111 . . . 110
111 . . . 101
100 . . . 001
100 . . . 000
≥ V
OUTPUT CODE
REF
/ 2
ENOB = (SINAD - 1.76) / 6.02
-FS =
FS =
ZS = COM
1 LSB =
- FS
Signal-to-Noise Plus Distortion
-V
V
REF
2
2
REF
4096
V
REF
+ V
+ V
Effective Number of Bits
COM
COM
INPUT VOLTAGE (LSB)
COM*
RMS
/ Noise
+FS - 1 LSB
RMS
REF
)
/ 2