MX674A MAXIM [Maxim Integrated Products], MX674A Datasheet - Page 11

• Manufacturer Part Number: MX674A
• Description: Industry-Standard, Complete 12-Bit ADCs
• Manufacturer: MAXIM [Maxim Integrated Products]

For systems which do not use or require full bus interfac-
ing, the MAX174/MX574A/MX674A can be operated in
a stand-alone mode directly linked through dedicated
input ports.
When configured in the stand-alone mode, conversion is
controlled by R/C. In addition, CS and A0 are wired low;
CE and 12/8 are wired high. To enable the three-state
buffers, set R/C low. A conversion starts when R/C is set
high. This allows either a high- or a low-pulse control sig-
nal. Shown in
this mode, the outputs, in response to the falling edge of
R/C, are forced into the high-impedance state and return
to valid logic-levels after the conversion is complete. The
STS output goes high following the R/C falling edge and
returns low when the conversion is complete.
A high-pulse conversion initiation is illustrated in
When R/C is high, the data lines are enabled. The next con-
version starts with the falling edge of R/C. The data lines
return and remain in high impedance state until another
R/C high pulse.
For best system performance, PCBs should be used for
the MAX174/MX574A/MX674A. Wire wrap boards are not
recommended. The layout of the board should ensure
that digital and analog signal lines are kept separated
from each other as much as possible. Care should be
taken not to run analog and digital lines parallel to each
other or digital lines underneath the MAX174/MX574A/
MX674A.
The recommended power-supply grounding practice is
shown in
chip reference is AGND. It should be connected directly
to the analog reference point of the system. The analog
and digital grounds should be connected together at the
package in order to gain all of the accuracy possible
from the MAX174/MX574A/MX674A in high digital noise
environments. In situations permitting, they can be con-
nected to the most accessible ground-reference point.
The preference is analog power return.
Figure
Figure 6
8. The ground reference point for the on-
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Analog Considerations
is the operation with a low pulse. In
Industry-Standard, Complete 12-Bit ADCs
Stand-Alone Operation
Application Hints
Physical Layout
Grounding
Figure
7.
MAX174/MX574A/MX674A
Figure 6. Low Pulse for R//C in Stand-Alone Mode
Figure 7. High Pulse for R//C in Stand-Alone Mode
Figure 8. Power-Supply Grounding Practice
V
EE
D0–11
CIRCUITRY
D0–11
S/H AND
STS
ANALOG
R/C
STS
R/C
GND
-15V
V
ANALOG SUPPLY
CC
t
t
DDR
HDR
t
DS
t
t
GND
HRH
HRL
V
EE
+15V
AGND
HIGH IMPEDANCE
MAX174
MX574A
MX674A
t
HDR
t
DS
V
CC
t
V
C
L
HIGH IMPEDANCE
DGND
DIGITAL SUPPLY
+5V
t
HS
GND
+5V
CIRCUITRY
DIGITAL
DGND