LTC1857/LTC1858/LTC1859
8-Channel, 12-/14-/16-Bit,
100ksps SoftSpan A/D
Converters with Shutdown
FEATURES
DESCRIPTION
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The LTC®1857/LTC1858/LTC1859 are 8-channel, low
power, 12-/14-/16-bit, 100ksps, analog-to-digital converters (ADCs). These SoftSpan™ ADCs can be softwareprogrammed for 0V to 5V, 0V to 10V, ±5V or ±10V input
spans and operate from a single 5V supply. The 8‑channel
multiplexer can be programmed for single-ended inputs
or pairs of differential inputs or combinations of both. In
addition, all channels are fault protected to ±25V. A fault
condition on any channel will not affect the conversion
result of the selected channel.
Sample Rate: 100ksps
8-Channel Multiplexer with ±25V Protection
Single 5V Supply
Software-Programmable Input Ranges:
n 0V to 5V, 0V to 10V, ±5V or ±10V
n Single-Ended or Differential
±3LSB INL for the LTC1859, ±1.5LSB INL for the
LTC1858, ±1LSB INL for the LTC1857
n Power Dissipation: 40mW (Typ)
n SPI/MICROWIRE™ Compatible Serial I/O
n Power Shutdown: Nap and Sleep
n Signal-to-Noise Ratio: 87dB (Typ) for the LTC1859
n Operates with Internal or External Reference
n Internal Synchronized Clock
n 28-Pin SSOP Package
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APPLICATIONS
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An onboard high performance sample-and-hold and precision reference minimize external components. The low
40mW power dissipation is made even more attractive with
two user selectable power shutdown modes. DC specifications include ±3LSB INL for the LTC1859, ±1.5LSB INL
for the LTC1858 and ±1LSB for the LTC1857.
The internal clock is trimmed for 5µs maximum conversion
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.
Industrial Process Control
Multiplexed Data Acquisition Systems
High Speed Data Acquisition for PCs
Digital Signal Processing
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. SoftSpan is
a trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
TYPICAL APPLICATION
100kHz, 12-Bit/14-Bit/16-Bit Sampling ADC
2.0
1.5
µP
CONTROL
LINES
1.0
10µF
10µF
3V TO 5V
5V
5V
10µF
2.5V
1µF
10µF
INL (LSB)
SOFTWARE-PROGRAMMABLE
SINGLE-ENDED OR
DIFFERENTIAL INPUTS
(0V TO 5V, 0V TO 10V,
±5V OR ±10V)
COM
CONVST
CH0 LTC1857/ RD
CH1 LTC1858/ SCK
CH2 LTC1859 SDI
CH3
DGND
CH4
SDO
CH5
BUSY
CH6
OVDD
DVDD
CH7
AVDD
MUXOUT+
MUXOUT–
AGND3
ADC+
AGND2
ADC–
REFCOMP
AGND1
VREF
LTC1859 Typical INL Curve
0.5
0
–0.5
–1.0
–1.5
–2.0
–32768
–16384
0
CODE
16384
32767
1859 TA02
185789fb
For more information www.linear.com/LTC1857
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