LTC1408 LINER [Linear Technology], LTC1408 Datasheet - Page 8

• Manufacturer Part Number: LTC1408
• Description: Channel, 14-Bit, 600ksps Simultaneous Sampling ADC with Shutdown
• Manufacturer: LINER [Linear Technology]

PI FU CTIO S
LTC1408
CH3
fully differentially with respect to CH3
or ±1.25V differential swing and a 0V to V
input range.
CH3
differentially with respect to CH3
±1.25V differential swing and a 0V to V
input range.
CH4
fully differentially with respect to CH4
or ±1.25V differential swing and a 0V to V
range.
CH4
differentially with respect to CH4
±1.25V differential swing and a 0V to V
range.
CH5
fully differentially with respect to CH5
or ±1.25V differential swing and a 0V to V
range.
CH5
differentially with respect to CH5
±1.25V differential swing and a 0V to V
range.
GND (PIN 22): Analog Ground for Reference. Analog
ground must be tied directly to the solid ground plane
under the part. Analog signal currents flow through this
connection. The 10µF reference bypass capacitor should
be returned to this pad.
V
and a solid analog ground plane with a 10µF ceramic
capacitor (or 10µF tantalum in parallel with 0.1µF ce-
ramic). Can be overdriven by an external reference voltage
between 2.55% and V
V
3V to the analog section. Bypass to the solid analog
ground plane with a 10µF ceramic capacitor (or 10µF
tantalum) in parallel with 0.1µF ceramic. Care should be
taken to place the 0.1µF bypass capacitor as close to
Pin 24 as possible. Pin 24 must be tied to Pin 25.
8
REF
CC
U
(Pin 24): 3V Positive Analog Supply. This pin supplies
+
–
+
–
+
–
(Pin 23): 2.5V Internal Reference. Bypass to GND
(Pin 14): Non-Inverting Channel 3. CH3
(Pin 15): Inverting Channel 3. CH3
(Pin 17): Non-Inverting Channel 4. CH4
(Pin 18): Inverting Channel 4. CH4
(Pin 20): Non-Inverting Channel 5. CH5
(Pin 21): Inverting Channel 5. CH5
U
U
DD
, V
CC
.
+
+
+
with a –2.5V to 0V, or
with a –2.5V to 0V, or
with a –2.5V to 0V, or
–
–
–
with a 0V to 2.5V,
with a 0V to 2.5V,
with a 0V to 2.5V,
DD
DD
DD
DD
–
–
–
absolute input
absolute input
absolute input
absolute input
operates fully
operates fully
operates fully
DD
DD
+
+
+
operates
absolute
operates
operates
absolute
V
3V to the logic section. Bypass to DGND pin and solid
analog ground plane with a 10µF ceramic capacitor (or
10µF tantalum in parallel with 0.1µF ceramic). Keep in
mind that internal digital output signal currents flow
through this pin. Care should be taken to place the 0.1µF
bypass capacitor as close to Pin 25 as possible. Pin 25
must be tied to Pin 24.
SEL2 (Pin 26): Most significant bit controlling the
number of channels being converted. In combination with
SEL1 and SEL0, 000 selects just the first channel (CH0) for
conversion. Incrementing SELx selects additional
channels(CH0–CH5) for conversion. 101, 110 or 111
select all 6 channels for conversion. Must be kept in a fixed
state during conversion and during the subsequent con-
version to read data.
SEL1 (Pin 27): Middle significance bit controlling the
number of channels being converted. In combination with
SEL0 and SEL2, 000 selects just the first channel (CH0) for
conversion. Incrementing SELx selects additional
channels for conversion. 101, 110 or 111 select all 6
channels (CH0–CH5) for conversion. Must be kept in a
fixed state during conversion and during the subsequent
conversion to read data.
SEL0 (Pin 28): Least significant bit controlling the
number of channels being converted. In combination with
SEL1 and SEL2, 000 selects just the first channel (CH0) for
conversion. Incrementing SELx selects additional
channels for conversion. 101, 110 or 111 select all 6
channels (CH0–CH5) for conversion. Must be kept in a
fixed state during conversion and during the subsequent
conversion to read data.
BIP (Pin 29): Bipolar/Unipolar Mode. The input differen-
tial range is 0V – 2.5V when BIP is LOW, and it is ±1.25
when BIP is HIGH. Must be kept in fixed state during
conversion and during subsequent conversion to read
data. When changing BIP between conversions the full
acquisition time must be allowed before starting the next
conversion. The output data is in 2’s complement
format for bipolar mode and straight binary format for
unipolar mode.
DD
(Pin 25): 3V Positive Digital Supply. This pin supplies
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