Datasheet LTC1290 (Analog Devices)

LTC1290 Single Chip 12-Bit Data Acquisition System
U FEATURES DESCRIPTIO
■ Software Programmable Features The LTC®1290 is a data acquisition component which – Unipolar/Bipolar Conversion contains a serial I/O successive approximation A/D con- – Four Differential/Eight Single-Ended Inputs verter. It uses LTCMOSTM switched capacitor technology – MSB- or LSB-First Data Sequence to perform either 12-bit unipolar or 11-bit plus sign bipolar – Variable Data Word Length A/D conversions. The 8-channel input multiplexer can be – Power Shutdown configured for either single-ended or differential inputs (or ■ Built-In Sample-and-Hold combinations thereof). An on-chip sample-and-hold is ■ Single Supply 5V or ±5V Operation included for all single-ended input channels. When the ■ Direct Four-Wire Interface to Most MPU Serial Ports LTC1290 is idle it can be powered down with a serial word and All MPU Parallel Ports in applications where low power consumption is desired. ■ 50kHz Maximum Throughput Rate The serial I/O is designed to be compatible with industry ■ Available in 20-Lead PDIP and SO Wide Packages
U
standard full duplex serial interfaces. It allows either MSB-
KEY SPECIFICATIO S
or LSB-first data and automatically provides 2's comple- ment output coding in the bipolar mode. The output data ■ Resolution: 12 Bits word can be programmed for a length of 8, 12 or 16 bits. ■ Fast Conversion Time: 13µs Max Over Temp This allows easy interface to shift registers and a variety of ■ Low Supply Current: 6.0mA processors. , LTC and LT are registered trademarks of Linear Technology Corporation. LTCMOS is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5287525.
U TYPICAL APPLICATIO 12-Bit 8-Channel Sampling Data Acquisition System
SINGLE-ENDED INPUT 1k 0V TO 5V OR ±5V CH0 VCC 5V ±15V OVERVOLTAGE RANGE* • + • 22µF CH1 ACLK 1N5817 • TANTALUM CH2 SCLK TO AND FROM CH3 DIN MICROPROCESSOR 1N4148 DIFFERENTIAL INPUT (+) CH4 DOUT LTC1290 ±5V COMMON MODE RANGE (–) CH5 CS • CH6 REF + LT®1027 8V TO 40V • + CH7 REF – • 4.7µF 1µF TANTALUM COM V – –5V DGND AGND 1N5817 0.1µF 1290 • TA01 * FOR OVERVOLTAGE PROTECTION ON ONLY ONE CHANNEL LIMIT THE INPUT CURRENT TO 15mA. FOR OVERVOLTAGE PROTECTION ON MORE THAN ONE CHANNEL LIMIT THE INPUT CURRENT TO 7mA PER CHANNEL AND 28mA FOR ALL CHANNELS. (SEE SECTION ON OVERVOLTAGE PROTECTION IN THE APPLICATIONS INFORMATION SECTION.) CONVERSION RESULTS ARE NOT VALID WHEN THE SELECTED OR ANY OTHER CHANNEL IS OVERVOLTAGED (VIN < V– OR VIN > VCC). 1290fe 1