ADS-947GE 查看數據表（PDF） - Murata Power Solutions
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ADS-947GE Datasheet PDF : 8 Pages
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®
®
ADS-947
DYNAMIC PERFORMANCE (Cont.)
S/H Acquisition Time
( to ±0.003%FSR, 4V step)
Overvoltage Recovery Time ➄
A/D Conversion Rate
DIGITAL OUTPUTS
MIN.
—
—
10
+25°C
TYP.
40
—
—
MAX.
45
100
—
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Output Coding
POWER REQUIREMENTS
+2.4
—
—
—
—
+0.4
—
—
–4
—
—
+4
Power Supply Ranges ➅
+5V Supply
–5.2V Supply
Power Supply Currents
+5V Supply
–5.2V Supply
Power Dissipation
Power Supply Rejection
+4.75
+5.0
+5.25
–4.75
–5.2
–5.45
—
+250
+260
—
–200
–210
—
2.0
2.25
—
—
±0.1
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.
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.
—
40
45
—
—
100
10
—
—
–40 to +100°C
MIN.
TYP.
MAX.
UNITS
—
40
45
ns
—
—
100
ns
10
—
—
MHz
+2.4
—
—
+2.4
—
—
Volts
—
—
+0.4
—
—
+0.4
Volts
—
—
–4
—
—
–4
mA
—
—
+4
—
—
+4
mA
Offset Binary
+4.75
–4.75
—
—
—
—
+5.0
+5.25
–5.2
–5.45
+250
+260
–200
–210
2.0
2.25
—
±0.1
+4.9
+5.0
+5.25
Volts
–4.9
–5.2
–5.45
Volts
—
+250
+260
mA
—
–200
–210
mA
—
2.0
2.25
Watts
—
—
±0.1 %FSR/%V
➃ Effective bits is equal to:
Full Scale Amplitude
(SNR + Distortion) – 1.76 + 20 log 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).
➅ The minimum supply voltages of +4.9V and –5.1V for ±VDD are required
for –40°C operation only. The minimum limits are +4.75V and –4.95V
when operating at +125°C
TECHNICAL NOTES
1. Obtaining fully specified performance from the ADS-947
requires careful 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 external 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
calibration hardware, make adjustments following warmup.
To avoid interaction, always adjust offset before gain.
3. Applying a start convert pulse while a conversion is in
progress (EOC = logic 1) will initiate a new and inaccurate
conversion cycle. Data for the interrupted and subsequent
conversions will be invalid.
4. A passive bandpass filter is used at the input of the A/D for
all production testing.
2kΩ
GAIN
ADJUST
+5V
SIGNAL
INPUT
1.98kΩ
50Ω
To Pin 21
of ADS-947
–5V
Figure 2. Optional ADS-947 Gain Adjust Calibration Circuit
3
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