LTC1090 Datasheet, PDF (1/28 Pages) Linear Technology – Single Chip 10-Bit Data Acquisition System

LTC1090
Single Chip 10-Bit Data
Acquisition System
FEATURES
■ _{Software Programmable Features:}
Unipolar/Bipolar Conversions
4 Differential/8 Single Ended Inputs
MSB or LSB First Data Sequence
Variable Data Word Length
■ _{Built-In Sample and Hold}
■ _{Single Supply 5V, 10V or ±5V Operation}
■ _{Direct 4 Wire Interface to Most MPU Serial Ports and}
All MPU Parallel Ports
■ _{30kHz Maximum Throughput Rate}
U
KEY SPECIFICATIO S
■ _{Resolution: 10 Bits}
■ _{Total Unadjusted Error (LTC1090A): ±1/2LSB Max}
■ _{Conversion Time: 22µs}
■ _{Supply Current: 2.5mA Max, 1.0mA Typ}
, LTC and LT are registered trademarks of Linear Technology Corporation.
LTCMOS is a trademark of Linear Technology Corp.
DESCRIPTIO
The LTC^®1090 is a data acquisition component which
contains a serial I/O successive approximation A/D con-
verter. It uses LTCMOS^TM switched capacitor technology
to perform either 10-bit unipolar, or 9-bit plus sign bipolar
A/D conversions. The 8-channel input multiplexer can be
configured for either single ended or differential inputs (or
combinations thereof). An on-chip sample and hold is
included for all single ended input channels.
The serial I/O is designed to be compatible with industry
standard full duplex serial interfaces. It allows either
MSB or LSB first data and automatically provides 2’s
complement output coding in the bipolar mode. The
output data word can be programmed for a length of 8, 10,
12 or 16 bits. This allows easy interface to shift registers
and a variety of processors.
The LTC1090A is specified with total unadjusted error
(including the effects of offset, linearity and gain errors)
less than ±0.5LSB.
The LTC1090 is specified with offset and linearity less than
±0.5LSB but with a gain error limit of ±2LSB for
applications where gain is adjustable or less critical.
TYPICAL APPLICATIO
LTC1090
DIFFERENTIAL
INPUT
FOR 8051 CODE SEE
APPLICATIONS INFORMATION
SECTION
MPU
(e.g., 8051)
5V
5V
–5V
T
BIPOLAR INPUT
UNIPOLAR
INPUTS
D_OUT
P1.1
D_IN
P1.2
SCLK
P1.3
CS
P1.4
SERIAL DATA
LINK
1.0
0.5
0.0
– 0.5
–1.0
0
Linearity Plot
512
OUTPUT CODE
1024
LTC1090 • TA02
(+)
– UNIPOLAR
(–) _INPUT
–5V
LTC1090 • TA01
1090fc
1