LTC1863L Linear Technology, LTC1863L Datasheet - Page 7

• Manufacturer Part Number: LTC1863L
• Description: (LTC1863L / LTC1867L) 12-/16-Bit 8-Channel 175ksps ADCs
• Manufacturer: Linear Technology

PI FU CTIO S
TYPICAL CO
CHO-CH7/COM (Pins 1-8): Analog Input Pins. Analog
inputs must be free of noise with respect to GND. CH7/
COM can be either a separate channel or the common
minus input for the other channels. Unused channels
should be tied to ground.
REFCOMP (Pin 9): Reference Buffer Output Pin. Bypass to
GND with 10µF tantalum capacitor in parallel with 0.1µF
ceramic capacitor (2.5V Nominal). To overdrive REFCOMP,
tie V
V
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.
TEST CIRCUITS
REF
U
REF
(Pin 10): 1.25V Reference Output. This pin can also
(A) Hi-Z TO V OH AND V OL TO V OH
to GND.
SDO
U
Load Circuits for Access Timing
3k
U U
U
C
ECTIO DIAGRA
L
(B) Hi-Z TO V OL AND V OH TO V OL
U
SDO
SINGLE-ENDED
DIFFERENTIAL
±1.25V
INPUTS
2.7V
INPUT
2.5V
3k
C
L
+
–
+
1863L7L TC01
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7/COM
U U
LTC1863L/
LTC1867L
REFCOMP
CS/CONV
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 configuration
word is shifted into this input.
GND (Pin 15): Analog and Digital GND.
V
GND with 10µF tantalum capacitor in parallel with 0.1µF
ceramic capacitor.
DD
V
GND
SDO
SCK
V
SDI
REF
DD
(Pin 16): Analog and Digital Power Supply. Bypass to
DIGITAL
I/O
SDO
Load Circuits for Output Float Delay
10µF
10µF
2.5V
(A) V OH TO Hi-Z
2.7V TO 3.6V
LTC1863L/LTC1867L
3k
1863L7L TCD
2.2µF
1.25V
C
L
SDO
(B) V OL TO Hi-Z
2.7V
1863L7L TC02
3k
C
L
1863l7lfa
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