LTC1857/LTC1858/LTC1859
8-Channel, 12-/14-/16-Bit,
100ksps SoftSpan A/D
Converters with Shutdown
FEATURES
DESCRIPTION
The LTC®1857/LTC1858/LTC1859 are 8-channel, low
power,12-/14-/16-bit,100ksps,analog-to-digitalconvert-
ers (ADCs). These SoftSpan™ ADCs can be software-
programmed for 0V to 5V, 0V to 10V, ±5V or ±10V inpꢀt
spans and operate from a single 5V sꢀpply. The 8-channel
mꢀltiplexer can be programmed for single-ended inpꢀts
or pairs of differential inpꢀts or combinations of both. In
addition, all channels are faꢀlt protected to ±25V. A faꢀlt
condition on any channel will not affect the conversion
resꢀlt of the selected channel.
n
Sample Rate: 100ksps
n
8-Channel Multiplexer with ±2ꢀ5 ꢁrꢂteꢃtiꢂn
n
Single ꢀ5 Supply
n
Sꢂftware-ꢁrꢂgrammable Input Ranges:
n
05 tꢂ ꢀ5, 05 tꢂ 105, ±ꢀ5 ꢂr ±105
Single-Ended ꢂr Differential
n
n
±±3SB Iꢄ3 fꢂr the 3TC18ꢀ9, ±1ꢅꢀ3SB Iꢄ3 fꢂr the
3TC18ꢀ8, ±13SB Iꢄ3 fꢂr the 3TC18ꢀ7
n
ꢁꢂwer Dissipatiꢂn: 40mW (Typ)
n
SꢁI/MICROWIRE™ Cꢂmpatible Serial I/O
n
Power Shꢀtdown: ꢂap and Sleep
An onboard high performance sample-and-hold and pre-
cision reference minimize external components. The low
40mWpowerdissipationismadeevenmoreattractivewith
twoꢀserselectablepowershꢀtdownmodes.DCspecifica-
tions inclꢀde ±±LSꢁ IꢂL for the LTC1859, ±1.5LSꢁ IꢂL
for the LTC1858 and ±1LSꢁ for the LTC1857.
n Signal-to-ꢂoise Ratio: 87dꢁ (Typ) for the LTC1859
n Operates with Internal or External Reference
n Internal Synchronized Clock
n 28-Pin SSOP Package
APPLICATIONS
Theinternalclockistrimmedfor5µsmaximꢀmconversion
time and the sampling rate is gꢀaranteed at 100ksps. A
separate convert start inpꢀt and data ready signal (BUSY)
ease connections to FIFOs, DSPs and microprocessors.
n
Indꢀstrial Process Control
n
Mꢀltiplexed Data Acqꢀisition Systems
High Speed Data Acqꢀisition for PCs
n
n
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
3TC18ꢀ9 Typiꢃal Iꢄ3 Curve
2.0
COM
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CONVST
1.5
1.0
0.5
0
RD
SCK
SDI
LTC1857/
LTC1858/
LTC1859
µP
CONTROL
LINES
SOFTWARE-PROGRAMMABLE
SINGLE-ENDED OR
DGND
SDO
BUSY
DIFFERENTIAL INPUTS
(0V TO 5V, 0V TO 10V,
5V OR 10V)
3V TO 5V
–0.5
OV
DD
DV
DD
AV
DD
5V
5V
+
MUXOUT
MUXOUT
–1.0
–
AGND3
AGND2
REFCOMP
10µF
10µF
10µF
+
–1.5
–2.0
ADC
–
ADC
AGND1
V
2.5V
–32768
–16384
0
16384
32767
REF
1µF
10µF
CODE
1859 TA02
185789fb
1
For more information www.linear.com/LTC1857