LTC1289_15 Datasheet, PDF (1/28 Pages) Linear Technology – 3 Volt Single Chip 12-Bit Data Acquisition System

LTC1289
3 Volt Single Chip 12-Bit
Data Acquisition System
FEATURES
■ _{Single Supply 3.3V or ±3.3V Operation}
■ _{Software Programmable Features}
Unipolar/Bipolar Conversions
4 Differential/8 Single-Ended Inputs
Variable Data Word Length
Power Shutdown
■ _{Built-In Sample-and-Hold}
■ _{Direct 4-Wire Interface to Most MPU Serial Ports}
and All MPU Parallel Ports
■ _{25kHz Maximum Throughput Rate}
■ _{Available in 20-Lead PDIP and 20-Lead SW Packages}
U
APPLICATIO S
■ _{Minimum Guaranteed Supply Voltage: 2.7V}
■ Resolution: 12 Bits
■ Fast Conversion Time: 26µs Max Over Temp
■ Low Supply Currents: 1.0mA
DESCRIPTIO
The LTC^®1289 is a 3V data acquisition component which
contains a serial I/O successive approximation A/D con-
verter. The device specifications are guaranteed at a
supply voltage of 2.7V. It uses LTCMOS^TM switched ca-
pacitor technology to perform a 12-bit unipolar, or 11-bit
plus sign bipolar A/D conversion. 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. When the LTC1289 is idle it can be powered
down in applications where low power consumption is
desired.
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 comple-
ment output coding in the bipolar mode. The output data
word can be programmed for a length of 8, 12 or 16 bits.
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.
TYPICAL APPLICATIO
Single Cell 3V 12-Bit Data Acquisition System
+3V
–
1/4 LTC1079
+
1N4148
10Ω
10µF
–3V
FOR OVERVOLTAGE PROTECTION ON
ONLY ONE CHANNEL LIMIT THE INPUT
CURRENT TO 15mA. FOR MORE THAN
ONE CHANNEL LIMIT THE INPUT
CURRENT TO 7mA PER CHANNEL AND
28mA FOR ALL CHANNELS.
CONVERSION RESULTS ARE NOT VALID
WHEN THE SELECTED OR ANY OTHER
CHANNEL IS OVERVOLTAGED (V_IN < V^–
or V_IN > V_CC).
CH0
V_CC
CH1
ACLK
CH2
SCLK
CH3
D_IN
CH4 _LTC1289 D_OUT
CH5
CS
CH6
REF⁺
CH7
REF^–
COM
V^–
DGND
AGND
TO AND
FROM
MPU
22µF
TANTALUM
10k
1N4148
10µF
22µF
LT1004-1.2
0.1µF 1N5817
BOOST
V⁺
CAP⁺
OSC
LTC1044
GND
LV
CAP^–
V_OUT
3V
LITHIUM
–3V
22µF
LTC1289 TA01
1289fb
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