Datasheet

LTC1863/LTC1867
7
18637fa
PIN FUNCTIONS
TYPICAL CONNECTION DIAGRAM
TEST CIRCUITS
3k
(A) Hi-Z TO V
OH
AND V
OL
TO V
OH
C
L
3k
5V
DNDN
(B) Hi-Z TO V
OL
AND V
OH
TO V
OL
C
L
18637 TC01
3k
(A) V
OH
TO Hi-Z
C
L
3k
5V
DNDN
(B) V
OL
TO Hi-Z
C
L
18637 TC02
Load Circuits for Access Timing Load Circuits for Output Float Delay
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7/COM
V
DD
GND
SDI
SDO
SCK
CS/CONV
V
REF
REFCOMP
LTC1863/
LTC1867
–
+
+
DIGITAL
I/O
5V
4.096V
10μF
2.2μF
2.5V
±2.048V
DIFFERENTIAL
INPUTS
4.096V
SINGLE-ENDED
INPUT
18637 TCD
CHO-CH7/COM (Pins 1-8): Analog Input Pins. Analog
i n p u t s m u s t b e f r e e o f n o i s e w i t h r e s p e c t t o G N D. C H 7/ C O M
can be either a separate channel or the common minus
input for the other channels.
REFCOMP (Pin 9): Reference Buffer Output Pin. Bypass
to GND with 10μF tantalum capacitor in parallel with
0.1μF ceramic capacitor (4.096V Nominal). To overdrive
REFCOMP, tie V
REF
to GND.
V
REF
(Pin 10): 2.5V Reference Output. This pin can also
be used as an external reference buffer input for improved
accuracy and drift. Bypass to GND with 2.2μF tantalum
capacitor in parallel with 0.1μF ceramic capacitor.
CS/CONV (Pin 11): This input provides the dual function
of initiating conversions on the ADC and also frames the
serial data transfer.
SCK (Pin 12): Shift Clock. This clock synchronizes the
serial data transfer.
SDO (Pin 13): Digital Data Output. The A/D conversion
result is shifted out of this output. Straight binary format
for unipolar mode and two’s complement format for
bipolar mode.
SDI (Pin 14): Digital Data Input Pin. The A/D confi guration
word is shifted into this input.
GND (Pin 15): Analog and Digital GND.
V
DD
(Pin 16): Analog and Digital Power Supply. Bypass to
GND with 10μF tantalum capacitor in parallel with 0.1μF
ceramic capacitor.