ADC-207MM Murata Power Solutions Inc, ADC-207MM Datasheet - Page 4
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ADC-207MM
Manufacturer Part Number
ADC-207MM
Description
Analog To Digital Converter
Manufacturer
Murata Power Solutions Inc
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USING TWO ADC-207s FOR 8-BIT RESOLUTION
resolution. The device A provides a typical 7-bit output. The OVERFLOW
signal of device A turns off device A and turns on the device B. The OVER-
FLOW signal of device A is also used as MSB for 8-bit operation. The device
B provides the other seven bits from the input signal. Figure 4 shows the
circuit connections for the application.
ANALOG IN
DATEL
CLOCK IN
REFERENCE
+5.12
Two ADC-207s (A and B) are cascadable for applications requiring 8-bit
OPTIONAL
MIDSCALE
IN
ADJUST
REFERENCE
®
GROUND
+5V
+5V
TURN
Figure 4. Using Two ADC-207s for 8-Bit Operation
10
NOTE: The output data bit numbering is offset by a
bit to the device B’s output.
18
6
8
4
1
9
3
6
8
1
4
9
3
+5 VOLTS
CLOCK IN
GROUND
CS1
+REFERENCE
ANALOG INPUT
CLOCK
CS2
–REFERENCE
CLOCK
+V
–REFERENCE
+REFERENCE
CS1
ANALOG INPUT
CS2
DD
ANALOG GROUND
ANALOG GROUND
+V
DD
18
7
7
0.01µF
DIG GND
DIG GND
OF
OF
B1
B2
B3
B4
B5
B6
B7
B1
B2
B3
B4
B5
B6
B7
®
10
11
12
13
14
15
16
17
10
11
12
13
14
15
16
17
2
2
• 11 Cabot Boulevard, Mansfi eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com
9
4
5
OVERFLOW
BIT 1 (MSB)
6
8
BIT2
BIT3
BIT4
BIT5
BIT6
BIT7
BIT8 (LSB)
20k
BEAT FREQUENCY AND ENVELOPE TESTS
test uses a 20MHz clock input to the ADC-207 with a 20.002MHz full-scale
sine wave input. Although the converter would not normally be used in this
mode because the input frequency violates Nyquist criteria for full recovery
of signal information, the test is an excellent demonstration of the ADC-
207’s high-frequency performance.
clock is that the output will be a 2kHz sinusoidal digital data array which
"walks" along the actual input at the 2kHz beat note frequency. Any inabil-
ity to follow the 20.002MHz input will be immediately obvious by plotting
the digital data array. Further arithmetic analysis may be done on the data
array to determine spectral purity, harmonic distortion, etc. This test is an
excellent indication of:
is a variation of the previous test but uses a 10.002MHz sinewave input to
give two overlapping cycles when the data is reconstructed by a D/A con-
verter output to an oscilloscope. The scope is triggered by the 20MHz clock
used by the A/D. Any asymmetry between positive and negative portions of
the signal will be very obvious. This test is an excellent indication of slew
rate capability. At the peaks of the envelope, consecutive samples swing
completely through the input voltage range.
10pF
Figure 5 shows an actual ADC-207 plot of the Beat Frequency Test. This
The effect of the 2kHz frequency difference between the input and the
Figure 6 shows an actual ADC-207 plot of the Envelope Test. This test
1. Full power input bandwidth of all 128 comparators.
2. Phase response linearity vs. instantaneous signal magnitude.
3. Comparator slew rate limiting.
(Any gain loss would show as signal distortion.)
(Phase problems would show as
improper codes.)
1
2
7-Bit, 20MHz, CMOS Flash A/D Converters
3
13
12
Figure 3. Optional Pulse Shaping Circuit
11
CLOCK OUT
MDA_ADC-207.B03 Page 4 of 6
ADC-207