
1
LTC1854/LTC1855/LTC1856
185456fa
COM
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
MUXOUT+
MUXOUT–
ADC+
ADC–
AGND1
CONVST
RD
SCK
SDI
DGND
SDO
BUSY
OVDD
DVDD
AVDD
AGND3
AGND2
REFCOMP
VREF
LTC1854/
LTC1855/
LTC1856
SOFTWARE-PROGRAMMABLE
SINGLE-ENDED OR
DIFFERENTIAL INPUTS
±10V BIPOLAR INPUT RANGE
10
μF
0.1
μF
10
μF
10
μF
0.1
μF
1
μF
10
μF
3V TO 5V
5V
2.5V
0.1
μF
μP
CONTROL
LINES
0.1
μF
8-Channel,
±10V Input
12-/14-/16-Bit, 100ksps ADC
Converters with Shutdown
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
supply and the 8-channel multiplexer can be programmed
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.
An onboard precision reference minimizes external com-
ponents. Power dissipation is 40mW at 100ksps and lower
in two power shutdown modes (27.5mW in Nap mode and
40
mW in Sleep mode.) DC specifications include ±3LSB
INL for the LTC1856,
±1.5LSB INL for the LTC1855 and
±1LSB for the LTC1854.
The internal clock is trimmed for 5
ms maximum conver-
sion time and the sampling rate is guaranteed at 100ksps.
A separate convert start input and data ready signal (BUSY)
ease connections to FIFOs, DSPs and microprocessors.
■ Single 5V Supply
■ Sample Rate: 100ksps
■ 8-Channel Multiplexer with
±30V Protection
■
±10V Bipolar Input Range
Single Ended or Differential
■
±3LSB INL for the LTC1856, ±1.5LSB INL for the
LTC1855,
±1LSB INL for the LTC1854
■ Power Dissipation: 40mW (Typ)
■ SPI/MICROWIRE
TM Compatible Serial I/O
■ Power Shutdown: Nap and Sleep
■ SINAD: 87dB (LTC1856)
■ Operates with Internal or External Reference
■ Internal Synchronized Clock
■ 28-Pin SSOP Package
100kHz, 12-Bit/14-/16-Bit Sampling ADC
■ Industrial Process Control
■
Multiplexed Data Acquisition Systems
■ High Speed Data Acquisition for PCs
■ Digital Signal Processing
LTC1856 Typical INL Curve
DESCRIPTIO
U
FEATURES
APPLICATIO S
U
TYPICAL APPLICATIO
U
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
CODE
–32768
INL
(LSB)
0
0.5
1.0
32767
185456 G01
–0.5
–1.0
–2.0
–16384
0
16384
–1.5
2.0
1.5