EVAL-AD7866CB AD [Analog Devices], EVAL-AD7866CB Datasheet - Page 8

• Manufacturer Part Number: EVAL-AD7866CB
• Description: Dual 1 MSPS, 12-Bit, 2-Channel SAR ADC with Serial Interface
• Manufacturer: AD [Analog Devices]

AD7866
PERFORMANCE CURVES
TPC 1 shows a typical FFT plot for the AD7866 at 1 MHz sample
rate and 300 kHz input frequency. TPC 2 shows the signal-to-
(noise + distortion) ratio performance versus input frequency for
various supply voltages while sampling at 1 MSPS with an SCLK
of 20 MHz.
TPC 3a through TPC 4b show the power supply rejection ratio
versus AV
ent conditions. The power supply rejection ratio is defined as the
ratio of the power in the ADC output at full-scale frequency f,
to the power of a 100 mV sine wave applied to the ADC AV
supply of frequency f
Typical Performance Characteristics
–115
–61
–63
–65
–67
–69
–71
–73
–75
–15
–35
–55
–75
–95
DD
0
10k
0
4098 POINT FFT
f
f
SNR = 70.31dB
THD = –85.47dB
SFDR = –86.64dB
T
supply ripple frequency for the AD7866 under differ-
SAMPLE
IN
A
= 300kHz
= 25 C
50
PSRR (dB) = 10 log (Pf/Pf
= 1MSPS
100
S
:
150
INPUT FREQUENCY – Hz
V
DD
FREQUENCY – kHz
200
= V
DRIVE
100k
250
V
= 4.75V
DD
300
= V
V
DD
DRIVE
V
350
= V
DD
S
DRIVE
= 3.6V
= V
)
400
DRIVE
= 2.7V
450
= 5.25V
1000k
500
DD
Pf = Power at frequency f in ADC output, Pf
quency f
peak-to-peak sine wave is coupled onto the AV
the digital supply is left unaltered. TPCs 3a and 3b show the
PSRR of the AD7866 when there is no decoupling on the supply,
while TPCs 4a and 4b show the PSRR with decoupling capacitors
of 10 µF and 0.1 µF on the supply.
TPC 5 and TPC 6 show typical DNL and INL plots for the AD7866.
TPC 7 shows a graph of the total harmonic distortion versus analog
input frequency for various source impedances.
TPC 8 shows a graph of total harmonic distortion versus analog
input frequency for various supply voltages. See Analog Input
section.
S
–100
–100
–10
–20
–30
–40
–50
–60
–70
–80
–90
–10
–20
–30
–40
–50
–60
–70
–80
–90
coupled onto the ADC AV
0
0
1k
1k
100mV p-p SINEWAVE ON AV
2.5V EXT REFERENCE ON D
V
T
100mV p-p SINEWAVE ON AV
2.5V EXT REFERENCE ON V
T
A
DD
A
V
V
= 25 C
= 25 C
DD
DD
= 4.75V
V
= 5.25V
= 2.7V
DD
= 3.6V
AV
AV
DD
DD
10k
10k
V
V
V
DD
DD
RIPPLE FREQUENCY – Hz
DD
RIPPLE FREQUENCY – Hz
= 2.7V
= 5.25V
= 3.6V
V
DD
CAP
REF
= 4.75V
DD
DD
DD
A, D
supply. Here a 100 mV
CAP
100k
100k
B
S
= power at fre-
DD
supply while
1M
1M