Datasheet

7
LTC1405
1405fa
PI FU CTIO S
UUU
+A
IN
(Pin 1): Positive Analog Input.
–A
IN
(Pin 2): Negative Analog Input.
V
CM
(Pin 3): 2.5V Reference Output.Optional input com-
mon mode for single supply operation. Bypass to GND
with a 1µF to 10µF ceramic.
SENSE (Pin 4): Reference Programming Pin. Ground
selects V
REF
= 4.096V. Short to V
REF
for 2.048V. Connect
SENSE to V
DD
to drive V
REF
with an external reference.
V
REF
(Pin 5): DAC Reference. Bypass to GND with a 1µF to
10µF ceramic.
GND (Pin 6): DAC Reference Ground.
V
DD
(Pin 7): Analog 5V Supply. Bypass to GND with a 1µF
to 10µF ceramic.
GND (Pin 8): Analog Power Ground.
D11 to D0 (Pins 9 to 20): Data Outputs. The output format
is two’s complement.
OGND (Pin 21): Output Logic Ground. Tie to GND.
OV
DD
(Pin 22): Positive Supply for the Output Logic.
Connect to Pin 23 for 5V logic. If not shorted to Pin 23,
bypass to GND with a 1µF ceramic.
V
DD
(Pin 23): Analog 5V Supply. Bypass to GND with a 1µF
ceramic.
GND (Pin 24): Analog Power Ground.
V
SS
(Pin 25): Negative Supply. Can be –5V or 0V. If V
SS
is
not shorted to GND, bypass to GND with a 1µF ceramic.
CLK (Pin 26): Conversion Start Signal. This active high
signal starts a conversion on its rising edge.
OF (Pin 27): Overflow Output. This signal is high when the
digital output is 011111111111 or 100000000000.
GAIN (Pin 28): Gain Select for Input PGA. 5V selects an
input gain of 1, 0V selects a gain of 2.