ADC12034 National Semiconductor Corporation, ADC12034 Datasheet - Page 5

• Manufacturer Part Number: ADC12034
• Description: Self-calibrating 12-bit Plus Sign Serial I/o A/d Converters With Mux And Sample/hold
• Manufacturer: National Semiconductor Corporation

CH0–CH7
COM
MUXOUT1,MUXOUT2 These are the multiplexer output
A/DIN1, /DIN2
These are the analog inputs of the
MUX. A channel input is selected by
the address information at the DI pin,
which is loaded on the rising edge of
SCLK into the address register (See
Tables 2, 3, 4).
The voltage applied to these inputs
should not exceed V
GND. Exceeding this range on an
unselected channel will corrupt the
reading of a selected channel.
This pin is another analog input pin.
It is used as a pseudo ground when
the analog multiplexer is single-end-
ed.
pins.
These are the converter input pins.
MUXOUT1 is usually tied to A/DIN1.
MUXOUT2 is usually tied to A/DIN2.
If external circuitry is placed be-
tween MUXOUT1 and A/DIN1, or
MUXOUT2 and A/DIN2 it may be
necessary to protect these pins. The
voltage at these pins should not ex-
A
+ or go below
5
V
V
V
DGND
AGND
REF
REF
A
+, V
+
−
D
+
ceed V
Figure 6).
This is the positive analog voltage
reference input. In order to maintain
accuracy, the voltage range of V
(V
5.0 V
cannot exceed V
recommended bypassing.
The negative voltage reference in-
put. In order to maintain accuracy,
the voltage at this pin must not go
below GND or exceed V
Figure 5).
These are the analog and digital
power supply pins. V
not connected together on the chip.
These pins should be tied to the
same power supply and bypassed
separately (see Figure 5). The oper-
ating voltage range of V
is 4.5 V
This is the digital ground pin (see
Figure 5).
This is the analog ground pin (see
Figure 5).
REF
DC
= V
A
DC
+
and the voltage at V
REF
or go below AGND (see
to 5.5 V
+ − V
A
+. See Figure 5 for
DC
REF
.
A
−) is 1 V
+
and V
www.national.com
A
+ and V
A
+. (See
D
DC
+
REF
are
REF
D
to
+
+