®
®
ADS-945
N
START
CONVERT
50ns typ.
N+1
N+2
10ns typ.
T/H
60ns typ.
Hold
Acquisition Time
40ns typ.
T/H
Hold
Hold
35ns max.
10ns typ.
90ns typ.
DATA N+1 VALID
OUTPUT
DATA
DATA N-1 VALID
DATA N VALID
INVALID
DATA
Note: Scale is approximately 10ns per division.
Figure 4. ADS-945 Timing Diagram
TIMING NOTES:
1. The ADS-945 is an edge-triggered device requiring no addi-
tional external timing signals. The rising edge of the start
convert pulse initiates a conversion.
2. A start convert pulse of 50ns is recommended when sam-
pling at 10MHz.
3. The falling edge of the subsequent start convert pulse (N+1)
or the rising edge of the N+2 pulse can be used to latch data
from conversion N (1 pipeline delay).
0
10
Amplitude Relative to Full Scale (dB)
20
30
40
50
60
70
80
90
100
110
120
130
140
150
0
500
kHz
1
MHz
1.5
MHz
2
MHz
2.5
MHz
3
MHz
3.5
MHz
4
MHz
4.5
MHz
5
MHz
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
Digital Output Code
This histogram represents the typical peak-to-peak
noise (including quantization noise) associated with
the ADS-945. 16,384 conversions were processed with
the input to the ADS-945 tied to analog ground.
Frequency
(fs = 10MHz, fin = 4.85MHz, Vin = 0.5dB, 16,384-point FFT)
Figure 5. ADS-945 FFT Analysis
Figure 6. ADS-945 Grounded Input Histogram
6
MURATA-PS [ MURATA POWER SOLUTIONS INC. ]
