LTC1291_15 Datasheet, PDF (1/20 Pages) Linear Technology – Single Chip 12-Bit Data Acquisition System

LTC1291
Single Chip 12-Bit
Data Acquisition System
FEATURES
s _{Built-In Sample-and-Hold}
s _{Single Supply 5V Operation}
s _{Power Shutdown}
s _{Direct 3- or 4-Wire Interface to Most MPU Serial}
Ports and All MPU Parallel Ports
s _{Two-Channel Analog Multiplexer}
s _{Analog Inputs Common Mode to Supply Rails}
s _{8-Pin DIP Package}
U
KEY SPECIFICATIO S
s _{Resolution: 12 Bits}
s _{Fast Conversion Time: 12µs Max Over Temp.}
s _{Low Supply Current:}
6.0mA (Typ) Active Mode
10µA (Max) Shutdown Mode
DESCRIPTIO
The LTC^®1291 is a data acquisition system that contains
a serial I/O successive approximation A/D converter. It
uses LTCMOS^TM switched capacitor technology to per-
form a 12-bit unipolar A/D conversion. The input multi-
plexer can be configured for either single-ended or differ-
ential inputs. An on-chip sample-and-hold is included on
the “+” input. When the LTC1291 is idle, it can be powered
down in applications where low power consumption is
desired. An external reference is not required because the
LTC1291 takes its reference from the power supply (V_CC).
All these features are packaged in an 8-pin DIP.
The serial I/O is designed to communicate without external
hardware to most MPU serial ports and all MPU parallel
I/O ports allowing data to be transmitted over three or four
wires. Given the accuracy, ease of use and small package
size, this device is well suited for digitizing analog signals
in remote applications where minimum number of inter-
connects, small physical size, and low power consump-
tion are important.
, LTC and LT are registered trademarks of Linear Technology Corporation.
LTCMOS^TM is a trademark of Linear Technology Corporation
TYPICAL APPLICATIO
2-Channel 12-Bit Data Acquisition System
22µF
TANTALUM ^5V
2-CHANNEL
MUX*
CS V_CC(V_REF)
CH0
CLK
LTC1291
CH1
D_OUT
0.1µF
DO
SCK
MC68HC11
MISO
GND
D_IN
MOSI
1291 TA01
*FOR OVERVOLTAGE PROTECTION, LIMIT THE INPUT CURRENT TO 15mA
PER PIN OR CLAMP THE INPUTS TO V_CC AND GND WITH 1N4148 DIODES.
CONVERSION RESULTS ARE NOT VALID WHEN THE SELECTED CHANNEL OR
THE OTHER CHANNEL IS OVERVOLTAGED (V_IN < GND OR V_IN > V_CC). SEE
SECTION ON OVERVOLTAGE PROTECTION IN THE APPLICATIONS INFORMATION.
Channel-to-Channel
INL Matching
0.5
0.4
0.3
0.2
0.1
0
– 0.1
– 0.2
– 0.3
– 0.4
– 0.5
0 512 1024 1536 2048 2560 3072 3584 4096
CODE
1291 TA02
1291fa
1