LTC1854/LTC1855/LTC1856
8-Channel, ±10V Input
12-/14-/16-Bit, 100ksps ADC
Converters with Shutdown
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FEATURES
DESCRIPTIO
The LTC®1854/LTC1855/LTC1856 are 8-channel, low
power, 12-/14-/16-bit, 100ksps, analog-to-digital con-
verters (ADCs). These ADCs operate from a single 5V
supplyandthe8-channelmultiplexercanbeprogrammed
for single-ended inputs, pairs of differential inputs, or
combinations of both. In addition, all channels are fault
protected to ±30V. A fault condition on any channel will
not affect the conversion result of the selected channel.
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Single 5V Supply
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Sample Rate: 100ksps
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8-Channel Multiplexer with ±30V Protection
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±10V Bipolar Input Range
Single Ended or Differential
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±3LSB INL for the LTC1856, ±1.5LSB INL for the
LTC1855, ±1LSB INL for the LTC1854
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Power Dissipation: 40mW (Typ)
SPI/MICROWIRETM Compatible Serial I/O
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An onboard precision reference minimizes external com-
ponents. Powerdissipationis40mWat100kspsandlower
in two power shutdown modes (27.5mW in Nap mode and
40mW in Sleep mode.) DC specifications include ±3LSB
INL for the LTC1856, ±1.5LSB INL for the LTC1855 and
±1LSB for the LTC1854.
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Power Shutdown: Nap and Sleep
SINAD: 87dB (LTC1856)
Operates with Internal or External Reference
Internal Synchronized Clock
28-Pin SSOP Package
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APPLICATIO S
The internal clock is trimmed for 5ms maximum conver-
sion time and the sampling rate is guaranteed at 100ksps.
Aseparateconvertstartinputanddatareadysignal(BUSY)
ease connections to FIFOs, DSPs and microprocessors.
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Industrial Process Control
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Multiplexed Data Acquisition Systems
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High Speed Data Acquisition for PCs
Digital Signal Processing
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
■
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TYPICAL APPLICATIO
100kHz, 12-Bit/14-/16-Bit Sampling ADC
LTC1856 Typical INL Curve
2.0
COM
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CONVST
1.5
1.0
0.5
0
RD
SCK
SDI
LTC1854/
LTC1855/
LTC1856
μP
CONTROL
LINES
SOFTWARE-PROGRAMMABLE
SINGLE-ENDED OR
DGND
SDO
BUSY
DIFFERENTIAL INPUTS
±10V BIPOLAR INPUT RANGE
–0.5
–1.0
–1.5
–2.0
3V TO 5V
5V
5V
OV
DV
AV
DD
DD
DD
+
MUXOUT
MUXOUT
–
AGND3
AGND2
REFCOMP
0.1μF
10μF
10μF
0.1μF
10μF
0.1μF
+
ADC
–
ADC
–32768
–16384
0
16384
32767
AGND1
V
2.5V
REF
CODE
1μF
10μF
0.1μF
185456 G01
185456fa
1