ADC-B119 Просмотр технического описания (PDF) - DATEL Data Acquisition products
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ADC-B119 Datasheet PDF : 8 Pages
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®
®
ADS-119
DIGITAL OUTPUTS
MIN.
+25°C
TYP.
MAX.
0 to +70°C
MIN.
TYP. MAX.
–55 to +125°C
MIN. TYP.
MAX.
UNITS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Output Coding
POWER REQUIREMENTS
+2.4
—
—
+2.4
—
—
+2.4
—
—
Volts
—
—
+0.4
—
—
+0.4
—
—
+0.4
Volts
—
—
–4
—
—
–4
—
—
–4
mA
—
—
+4
—
—
+4
—
—
+4
mA
Offset Binary
Power Supply Ranges
+5V Supply
–5V Supply
Power Supply Current
+5V Supply
–5V Supply
Power Dissipation
Power Supply Rejection
+4.75
+5.0
+5.25
+4.75
–4.75
–5.0
–5.25
–4.75
+5.0
+5.25
+4.9
–5.0
–5.25
–4.9
+5.0
+5.25
Volts
–5.0
–5.25
Volts
—
+200
+215
—
+200
+215
—
+200
+215
mA
—
–180
–205
—
–180
–205
—
–180
–205
mA
—
1.8
2.1
—
1.8
2.1
—
1.8
2.1
Watts
—
—
±0.01
—
—
±0.01
—
—
±0.01 %FSR/%V
Footnotes:
All power supplies must be on before applying a start convert pulse. All supplies
and the clock (START CONVERT) must be present during warmup periods. The
device must be continuously converting during this time. There is slight
degradation in performance when using ±12V supplies.
See ordering information for availability of ±5V input range. Contact DATEL for
availability of other input voltage ranges.
A 200ns wide start convert pulse is used for all production testing. Only the rising
edge of the start convert pulse is required for the device to operate
(edge-triggered).
Effective bits is equal to:
Full Scale Amplitude
(SNR + Distortion) – 1.76 + 20 log Actual Input Amplitude
6.02
This is the time required before the A/D output data is valid after the analog input
is back within the specified range.
TECHNICAL NOTES
1. Obtaining fully specified performance from the ADS-119
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, 18, and 23) 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-119 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 3 and 4. For
operation without adjustment, tie pin 17 to analog ground.
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.
4. Data is valid only for the time period (55ns, typical) shown in
Figure 2 even if the device is sampling at less than 10MHz.
N
N+1
START
CONVERT
50ns typ.
INTERNAL S/H
INTERNAL EOC
DATA
VALID
10ns typ.
Hold
65ns typ.
Acquisition Time
30ns min.
35ns typ.
37ns max.
15ns typ.
20ns typ.
Conversion Time
Hold
72ns min.
80ns typ.
83ns max.
35ns typ.
40ns typ.
±5ns
60ns typ.
40ns typ.
±5ns
10ns typ.
DATA
DATA N-1 VALID
INVALID DATA
55ns typ.
Scale is approximately 5ns per division.
45ns typ.
INVALID DATA
DATA N VALID
Figure 2. ADS-119 Timing Diagram
INVALID DATA
3
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