LTC1857 Datasheet, PDF (1/20 Pages) Linear Integrated Systems – 8-Channel, 12-/14-/16-Bit, 100ksps SoftSpan A/D Converters with Shutdown

LTC1857/LTC1858/LTC1859
8-Channel, 12-/14-/16-Bit,
100ksps SoftSpan A/D Converters
with Shutdown
FEATURES
■ _{Sample Rate: 100ksps}
■ _{8-Channel Multiplexer with ±25V Protection}
■ _{Single 5V Supply}
■ _{Software-Programmable Input Ranges:}
0V to 5V, 0V to 10V, ±5V or ±10V
Single Ended or Differential
■ _{±3LSB INL for the LTC1859, ±1.5LSB INL for the}
LTC1858, ±1LSB INL for the LTC1857
■ _{Power Dissipation: 40mW (Typ)}
■ _{SPI/MICROWIRE}^TM _{Compatible Serial I/O}
■ _{Power Shutdown: Nap and Sleep}
■ _{Signal-to-Noise Ratio: 87dB (Typ) for the LTC1859}
■ _{Operates with Internal or External Reference}
■ _{Internal Synchronized Clock}
■ _{28-Pin SSOP Package}
U
APPLICATIO S
■ _{Industrial Process Control}
■ _{Multiplexed Data Acquisition Systems}
■ _{High Speed Data Acquisition for PCs}
■ _{Digital Signal Processing}
DESCRIPTIO
The LTC^®1857/LTC1858/LTC1859 are 8-channel, low
power, 12-/14-/16-bit, 100ksps, analog-to-digital con-
verters (ADCs). These SoftSpan^TM ADCs can be software-
programmed for 0V to 5V, 0V to 10V, ±5V or ±10V input
spans and operate from a single 5V supply. The 8-chan-
nel 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.
An onboard high performance sample-and-hold and pre-
cision reference minimize external components. The low
40mW power dissipation is made even more attractive
with two user selectable power shutdown modes. DC speci-
fications 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 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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
SoftSpan is a trademark of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
TYPICAL APPLICATIO
100kHz, 12-Bit/14-Bit/16-Bit Sampling ADC
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
OV_DD
CH7
MUXOUT⁺
MUXOUT^–
DV_DD
AV_DD
AGND3
ADC⁺
AGND2
ADC^–
REFCOMP
AGND1
V_REF
µP
CONTROL
LINES
10µF
10µF
1µF
10µF
3V TO 5V
5V
5V
10µF
2.5V
LTC1859 Typical INL Curve
2.0
1.5
1.0
0.5
0
– 0.5
–1.0
–1.5
–2.0
–32768 –16384
0
CODE
16384 32767
1859 TA02
185789f
1