Datasheet LTC1289 (Analog Devices)

LTC1289 3 Volt Single Chip 12-Bit Data Acquisition System
U FEATURES DESCRIPTIO
■ Single Supply 3.3V or ±3.3V Operation The LTC®1289 is a 3V data acquisition component which ■ Software Programmable Features contains a serial I/O successive approximation A/D con- Unipolar/Bipolar Conversions verter. The device specifications are guaranteed at a 4 Differential/8 Single-Ended Inputs supply voltage of 2.7V. It uses LTCMOSTM switched ca- Variable Data Word Length pacitor technology to perform a 12-bit unipolar, or 11-bit Power Shutdown plus sign bipolar A/D conversion. The 8 channel input ■ Built-In Sample-and-Hold multiplexer can be configured for either single-ended or ■ Direct 4-Wire Interface to Most MPU Serial Ports differential inputs (or combinations thereof). An on-chip and All MPU Parallel Ports sample and hold is included for all single-ended input ■ 25kHz Maximum Throughput Rate channels. When the LTC1289 is idle it can be powered ■ Available in 20-Lead PDIP and 20-Lead SW Packages down in applications where low power consumption is desired.
U
The serial I/O is designed to be compatible with industry
APPLICATIO S
standard full duplex serial interfaces. It allows either MSB- ■ Minimum Guaranteed Supply Voltage: 2.7V or LSB- first data and automatically provides 2’s comple- ■ Resolution: 12 Bits ment output coding in the bipolar mode. The output data ■ Fast Conversion Time: 26µs Max Over Temp word can be programmed for a length of 8, 12 or 16 bits. ■ Low Supply Currents: 1.0mA This allows easy interface to shift registers and a variety of processors. , LT, LTC and LTM 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.
U TYPICAL APPLICATIO Single Cell 3V 12-Bit Data Acquisition System
+3V CH0 VCC + 3V 1N4148 CH1 ACLK 22µF 10k LITHIUM – TANTALUM CH2 SCLK 10Ω TO AND BOOST V+ 1/4 LTC1079 CH3 DIN FROM CAP+ OSC + MPU CH4 + LTC1044 LTC1289 DOUT 10µF 1N4148 10 GND LV µF CH5 CS CAP– VOUT –3V –3V CH6 REF+ + LT1004-1.2 CH7 REF– 22µF + 22µF FOR OVERVOLTAGE PROTECTION ON ONLY ONE CHANNEL LIMIT THE INPUT COM V– CURRENT TO 15mA. FOR MORE THAN DGND AGND ONE CHANNEL LIMIT THE INPUT 0.1µF 1N5817 CURRENT TO 7mA PER CHANNEL AND 28mA FOR ALL CHANNELS. CONVERSION RESULTS ARE NOT VALID WHEN THE SELECTED OR ANY OTHER LTC1289 TA01 CHANNEL IS OVERVOLTAGED (VIN < V– or VIN > VCC). 1289fb 1