Datasheet

ADS7815
5
SBAS065B
www.ti.com
BASIC OPERATION
Figure 1 shows the recommended circuit for operation of the
ADS7815. 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
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 ADS7815 sample and
hold returns to the sample mode and begins acquiring the
input signal for the next conversion. Allowing 4µs between
falling edges of the convert pulse signal assures accurate
acquisition of the analog input.
FIGURE 1. Basic Operation.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
V
IN
GND
REF
CAP
GND
D15
D14
D13
D12
D11
D10
D9
D8
GND
28
27
26
25
24
23
22
21
20
19
18
17
16
15
+V
S
+V
S
BUSY
CS
R/C
–V
S
D0
D1
D2
D3
D4
D5
D6
D7
ADS7815
R
1
75Ω
+5V
–5V
+
2.2µF
C
4
0.1µF
C
6
+
2.2µF
C
3
0.1µF
C
5
Convert Pulse
74HC00
100ns min
µProcessor
Bus
µProcessor
Bus
+5V
0.1µF
C
1
+
10µF
C
2
–5V
OC
0.1µF
C
7
+
10µF
C
8
2
3
4
5
6
7
8
9
1D
2D
3D
4D
5D
6D
7D
8D
1Q
2Q
3Q
4Q
5Q
6Q
7Q
8Q
1
10
OC
CLK
74HC574
2
3
4
5
6
7
8
9
1D
2D
3D
4D
5D
6D
7D
8D
1Q
2Q
3Q
4Q
5Q
6Q
7Q
8Q
1
10
OC
CLK
74HC574
R
2
10Ω
OPA628