1
LTC1091/LTC1092
LTC1093/LTC1094
1-, 2-, 6- and 8-Channel, 10-Bit
Serial I/O Data Acquisition Systems
■
Programmable Features
– Unipolar/Bipolar Conversions
–
Differential/Single-Ended Multiplexer
Configurations
■
Sample-and-Holds
■
Single Supply 5V, 10V or ±5V Operation
■
Direct 3- or 4-Wire Interface to Most MPU Serial
Ports and All MPU Parallel I/O Ports
■
Analog Inputs Common Mode to Supply Rails
■
Resolution: 10 Bits
■
Total Unadjusted Error (A Grade): ±1LSB Over Temp
■
Fast Conversion Time: 20µs
■
Low Supply Current
LTC1091: 3.5mA Max, 1.5mA Typ
LTC1092/LTC1093/LTC1094: 2.5mA Max, 1mA Typ
5V
ANALOG INPUT #1
0V TO 5V RANGE
ANALOG INPUT #2
0V TO 5V RANGE
CLK
D
OUT
D
IN
CS
CH0
CH1
GND
LTC1091
MPU
(e.g., 8051)
P1.4
P1.3
P1.2
1091 TA01
8
7
6
5
1
2
3
4
SERIAL DATA LINK
FOR 8051 CODE SEE
APPLICATIONS INFORMATION
SECTION
V
CC
(V
REF
)
4.7µF
REFERENCE VOLTAGE (V)
0
LINEARITY ERROR (LSB = • V
REF
)
1.25
1.00
0.75
0.50
0.25
0
4
1091 TA02
1
2
3
5
1
1024
V
CC
= 5V
The LTC
®
1091/LTC1092/LTC1093/LTC1094 10-bit data
acquisition systems are designed to provide complete
function, excellent accuracy and ease of use when digitiz-
ing analog data from a wide variety of signal sources and
transducers. Built around a 10-bit, switched capacitor,
successive approximation A/D core, these devices include
software configurable analog multiplexers and bipolar and
unipolar conversion modes as well as on-chip sample-
and-holds. On-chip serial ports allow efficient data trans-
fer to a wide range of microprocessors and microcontrol-
lers. These circuits can provide a complete data acquisi-
tion system in ratiometric applications or can be used with
an external reference in others.
The high impedance analog inputs and the ability to
operate with reduced spans (below 1V full scale) allow
direct connection to sensors and transducers in many
applications, eliminating the need for gain stages.
An efficient serial port communicates without external
hardware to most MPU serial ports and all MPU parallel
I/O ports allowing eight channels of data to be transmitted
over as few as three wires. This, coupled with low power
consumption, makes remote location possible and facili-
tates transmitting data through isolation barriers.
Temperature drift of offset, linearity and full-scale error
are all extremely low (1ppm/°C typically) allowing all
grades to be specified with offset and linearity errors of
±0.5LSB maximum over temperature. In addition, the A
grade devices are specified with full-scale error and total
unadjusted error (including the effects of offset, linearity
and full-scale errors) of ±1LSB maximum over tempera-
ture. The lower grade has a full-scale specification of
±2LSB for applications where full scale is adjustable or
less critical.
, LTC and LT are registered trademarks of Linear Technology Corporation.
FEATURES
DESCRIPTIO
U
TYPICAL APPLICATION
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