AD9040A Datasheet, PDF (9/12 Pages) Analog Devices – 10-Bit 40 MSPS A/D Converter

AD9040A
Figure 8. PCB Top View
DAC Reconstruction
The AD9040A evaluation board provides an onboard AD9721
reconstruction DAC for observing the digitized analog input
signal. The AD9721 is terminated into 51 ohms to provide a
1 V p-p signal at the output (RC OUTPUT).
Output Data
The output data bits are latched with a CMOS 74AC574 which
drives a 40-pin connector (AMP p/n 102153-9). The data and
clock signals are available on the connector per the pin assign-
ments shown on the schematic of the evaluation board. Output
data are available on the falling edge of the clock.
Figure 9. PCB Bottom View
Table II. Digital Coding
Analog Voltage
Input Level
Out-of-
Range Digital Output
+1.002 V Positive Full Scale + 1 LSB 1
Positive Full Scale
0
+1 V
Full Scale – 1 LSB
0
MSB . . . LSB
1111111111
1111111111
1111111110
+1/2 V
Positive 1/2 Scale
1/2 Scale – 1 LSB
0
1100000000
0
1011111111
0V
Bipolar Zero
0
10000000000
0
01111111111
–1/2 V
1/2 Scale + 1 LSB
Negative 1/2 Scale
0
0100000000
0
0011111111
Full Scale + 1 LSB
0
–1 V
Negative Full Scale
0
–1.002 V Negative Full Scale – 1 LSB 1
0000000001
0000000000
0000000000
REV. B
–9–