Datasheet

6
®
ADS7818
TYPICAL PERFORMANCE CURVES (Cont.)
At T
A
= +25°C, V
CC
= +5V, f
SAMPLE
= 500kHz, f
CLK
= 16 • f
SAMPLE
, and internal +2.5V reference, unless otherwise specified.
CHANGE IN SIGNAL-TO-NOISE RATIO
and SIGNAL-TO-(NOISE+DISTORTION)
vs TEMPERATURE
–20–40 100
Temperature (°C)
Delta from +25°C (dB)
0.2
0.1
0.0
–0.1
–0.2
–0.3
0.3
0 20 40 60 80
SINAD
SNR
f
IN
= 100kHz, –0.2dB
CHANGE IN SPURIOUS FREE DYNAMIC RANGE
AND TOTAL HARMONIC DISTORTION
vs TEMPERATURE
–20–40 100
Temperature (°C)
SFDR Delta from +25°C (dB)
THD Delta from +25°C (dB)
0.5
0.0
–0.5
–1.0
–1.5
–2.0
1.0
–0.5
0.0
0.5
1.0
1.5
2.0
–1.0
0 20 40 60 80
THD
❉
SFDR
❉
First nine harmonics
f
IN
= 100kHz, –0.2dB
of the input frequency
0
FREQUENCY SPECTRUM
(4096 Point FFT; f
IN
= 247kHz, –0.2dB)
Amplitude (dB)
–100
–80
–60
–40
–20
0 25062.5 187.5125
Frequency (kHz)
–120
SPURIOUS FREE DYNAMIC RANGE AND
TOTAL HARMONIC DISTORTION
vs INPUT FREQUENCY
10k 100k1k 1M
Input Frequency (Hz)
SFDR (dB)
THD (dB)
85
80
75
70
65
90
– 85
– 80
– 75
– 70
– 65
– 90
THD
❉
❉
First nine harmonics
of the input frequency
SFDR
SIGNAL-TO-NOISE RATIO and
SIGNAL-TO-(NOISE+DISTORTION)
vs INPUT FREQUENCY
10k 100k1k 1M
Input Frequency (Hz)
SNR and SINAD (dB)
74
72
70
68
66
64
76
SINAD
SNR