ADS7811 Burr-Brown Corporation, ADS7811 Datasheet - Page 6

• Manufacturer Part Number: ADS7811
• Description: 16-Bit 250kHz Sampling CMOS ANALOG-to-DIGITAL CONVERTER
• Manufacturer: Burr-Brown Corporation

BASIC OPERATION
Figure 1 shows the recommended circuit for operation of the
ADS7811. A falling edge on the convert pulse signal places
the sample and hold into the hold mode and initiates a
conversion. When the conversion is complete, the pins D15
through D0 become active and the result of the conversion
FIGURE 1. Basic Operation.
OPA628
75
+5V
–5V
R
1
®
ADS7811
2.2µF
2.2µF
C
C
3
4
+
+
0.1µF
0.1µF
C
C
5
6
10
R
2
10
11
12
13
14
1
2
3
4
5
6
7
8
9
V
GND
REF
CAP
GND
D15
D14
D13
D12
D11
D10
D9
D8
GND
IN
ADS7811
BUSY
+V
+V
R/C
–V
CS
D0
D1
D2
D3
D4
D5
D6
D7
S
S
S
28
27
26
25
24
23
22
21
20
19
18
17
16
15
6
is placed on these outputs. In the circuit shown in Figure 1,
the rising edge of BUSY latches the result into the 74HC574s.
After the conversion is complete, the ADS7811 sample and
hold returns to the sample mode and begins acquiring the
input signal for the next conversion. Allowing 4 s between
falling edges of the convert pulse signal assures adequate
acquisition time for the internal sample and hold.
0.1µF
0.1µF
C
C
1
7
10
10
+
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
74HC00
+
OC
CLK
OC
CLK
1D
2D
3D
4D
5D
6D
7D
8D
1D
2D
3D
4D
5D
6D
7D
8D
10µF
10µF
74HC574
74HC574
C
C
2
8
–5V
1Q
2Q
3Q
4Q
5Q
6Q
7Q
8Q
1Q
2Q
3Q
4Q
5Q
6Q
7Q
8Q
+5V
Convert Pulse
3.3µs max
100ns min
µProcessor
µProcessor
Bus
OC
Bus