ADS-947GE-QL-C Просмотр технического описания (PDF) - DATEL Data Acquisition products
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ADS-947GE-QL-C Datasheet PDF : 9 Pages
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ADS-947
14-Bit, 10MHz Sampling A/D Converters
+25°C
DIGITAL OUTPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Output Coding
MIN.
TYP.
MAX.
+2.4
—
—
—
—
+0.4
—
—
–4
—
—
+4
POWER REQUIREMENTS
Power Supply Ranges
+5V Supply
–5V Supply
Power Supply Currents
+5V Supply
–5V Supply
Power Dissipation
Power Supply Rejection
+4.75
–4.75
—
—
—
—
+5.0
–5.2
+250
–150
2.2
—
+5.25
–5.45
+270
–170
2.2
±0.05
Footnotes:
➀ All power supplies should be on before applying a start convert pulse. All supplies
and the clock (start convert pulses) must be present during warmup periods. The
device must be continuously converting during this time.
➁ Contact DATEL for other input voltage ranges; the range for ADS-947MC-31122 is
±0.5 Volts.
➂ A 10MHz clock with a 20ns positive pulse width is used for all production testing.
See Timing Diagram, figure 4, for more details.
0 TO +70°C
MIN.
TYP.
MAX.
+2.4
—
—
—
—
+0.4
—
—
–4
—
—
+4
Offset Binary
–40 TO +100°C
MIN.
TYP.
MAX.
+2.4
—
—
—
—
+0.4
—
—
–4
—
—
+4
UNITS
Volts
Volts
mA
mA
+4.75
+5.0
+5.25
+4.9
–4.75
–5.0
–5.45
–4.9
+5.0
+5.25
Volts
–5.0
–5.45
Volts
—
+250
+270
—
+250
+270
mA
—
–150
–170
—
–150
–170
mA
—
2.2
2.2
—
2.2
2.2
Watts
—
—
±0.05
—
—
±0.05 %FSR/%V
➃ Effective bits is equal to:
(SNR + Distortion) – 1.76 +
20 log
Full Scale Amplitude
Actual Input Amplitude
6.02
➄ This is the time required before the A/D output data is valid once the analog input
is back within the specified range. This time is only guaranteed if the input does
not exceed ±2.2V (S/H saturation voltage).
TECHNICAL NOTES
1. Obtaining fully specified performance from the ADS-947 requires care-
ful attention to pc card layout and power supply decoupling. The device’s
analog and digital ground systems are connected to each other internally.
For optimal performance, tie all ground pins (14, 19 and 24) directly to a
large analog ground plane beneath the package.
Bypass all power supplies to ground with 4.7μF tantalum capacitors in
parallel with 0.1μF ceramic capacitors. Locate the bypass capacitors as
close to the unit as possible.
2. The ADS-947 achieves its specified accuracies without the need for exter-
nal calibration. If required, the device’s small initial offset and gain errors
can be reduced to zero using the adjustment circuitry shown in Figures
2 and 3. When using this circuitry, or any similar offset and gain calibra-
tion hardware, make adjustments following warmup. To avoid interaction,
always adjust offset before gain.
3. A passive bandpass filter is used at the input of the A/D for all production
testing.
2k:
GAIN
ADJUST
+5V
SIGNAL
INPUT
1.98k:
50:
To Pin 21
of ADS-947
–5V
Figure 2. Optional ADS-947 Gain Adjust Calibration Circuit
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com
MDA_ADS-947.D01 Page 3 of 9
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