Owner's manual

__________Applications Information
Noise
To minimize noise coupling, keep both the input signal
lead to AIN and the signal return lead from AGND as
short as possible. If this is not possible, a shielded
cable or a twisted-pair transmission line is recommend-
ed. Additionally, potential differences between the ADC
ground and the signal-source ground should be mini-
mized, since these voltage differences appear as
errors superimposed on the input signal. To minimize
system noise pickup, keep the driving source resis-
tance below 2kΩ.
Proper Layout
For PC board layouts, take care to keep digital lines
well separated from any analog lines. Establish a sin-
gle-point, analog ground (separate from the digital sys-
tem ground) near the MX7575/MX7576. This analog
ground point should be connected to the digital system
ground through a single-track connection only. Any
supply or reference bypass capacitors, analog input fil-
ter capacitors, or input signal shielding should be
returned to the analog ground point.
__Functional Diagrams (continued)
MX7575/MX7576
CMOS, µP-Compatible, 5µs/10µs, 8-Bit ADCs
______________________________________________________________________________________ 11
17


16
5
15
18
9
+5V
+5V
+5V
47µF
47µF
0.1µF
R6
3.3k
R7
10k
R1
1k
R2
820Ω
AGND DGND
R3
500Ω
INPUT VOLTAGE
R5
5k
R4
8.2k
0.1µF
TLC271
+5V
+
D7–D0
DATA OUT
C
L

100pF
2%
R
CLK
REF


AIN
CLK
V
DD
MX7575
ICL8069
1.2V
REFERENCE
111...111
111...110

100...010
100...001
100...000
011...111
011...110

000...001
000...000
OUTPUT
CODE
-FS
2
-1/2LSB
1/2LSB
FS
2
2FS
256
-1LSB
FS = 2V
REF

1LSB =
AIN
Figure 18a. MX7575 Bipolar Configuration
Figure 18b. Nominal Transfer Characteristic for Bipolar
Operation
DAC
COMP
LATCH AND
THREE-STATE
OUTPUT DRIVERS
SAR
CLOCK
OSCILLATOR
CONTROL
LOGIC
AIN
AGND
REF
CLK
CS
RD
V
DD
BUSY DGND
MODE
16
18
49
6
14
D7
D0
15
17
5
1
2
3
MX7576
.
.