LTC1291 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}
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 LTC1291 is a data acquisition system that contains a
serial I/O successive approximation A/D converter. It uses
LTCMOS^TM switched capacitor technology to perform a
12-bit unipolar A/D conversion. The input multiplexer can
be configured for either single-ended or differential in-
puts. 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.
LTCMOS^TM is a trademark of Linear Technology Corporation
TYPICAL APPLICATI
2-CHANNEL
MUX*
2-Channel 12-Bit Data Acquisition System
22µF
TANTALUM ^+5V
CS
V_CC(V_REF)
CH0
CLK
LTC1291
CH1
D_OUT
0.1µF
DO
SCK
MC68HC11
MISO
GND
D_IN
MOSI
*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.
1291 TA01
Channel-to-Channel
INL Matching
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0.1
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CODE
1291 TA02
1