
5
LTC1409
Note 11: The falling CONVST edge starts a conversion. If CONVST returns
high at a critical point during the conversion it can create small errors. For
best results ensure that CONVST returns high either within 650ns after
conversion start or after BUSY rises.
TI I G CHARACTERISTICS
W U
Note 12: Signal-to-noise ratio (SNR) is measured at 100kHz and distortion
is measured at 400kHz. These results are used to calculate signal-to-noise
plus distortion (SINAD).
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
S/(N + D) vs Input Frequency
and Amplitude
INPUT FREQUENCY (Hz)
1k
SIGNAL/(NOISE
+
DISTORTION)
(dB)
80
70
60
50
40
30
20
10
0
10k
100k
LTC1409 TPC01
1M
10M
VIN = 0dB
VIN = 20dB
VIN = 60dB
INPUT FREQUENCY (Hz)
1k
SIGNAL/(NOISE
+
DISTORTION)
(dB)
80
70
60
50
40
30
20
10
0
10k
100k
LTC1409 TPC02
1M
10M
Signal-to-Noise Ratio vs
Input Frequency
Spurious-Free Dynamic Range vs
Input Frequency
INPUT FREQUENCY (Hz)
10k
SPURIOUS-FREE
DYNAMIC
RANGE
(dB)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
100k
1M
10M
LTC1409 TPC04
Distortion vs Input Frequency
INPUT FREQUENCY (Hz)
AMPLITUDE
(dB
BELOW
THE
FUNDAMENTAL)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
1k
100k
1M
10M
LTC1409 TPC03
10k
THD
3RD
2ND
Intermodulation Distortion Plot
FREQUENCY (Hz)
0
AMPLITUDE
(dB)
0
–20
–40
–60
–80
–100
–120
100k
200k
300k
400k
LTC1409 TPC05
50k
150k
250k
350k
fb – fa
2fb – fa
2fa – fb
2fa
2fb
3fb
fa + 2fb
3fa
2fa + fb
fSAMPLE = 800kHz
fIN1 = 88.19580078kHz
fIN2 = 111.9995117kHz
fa + fb