lt1293 Linear Technology Corporation, lt1293 Datasheet

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lt1293

Manufacturer Part Number
lt1293
Description
Single Chip 12-bit Data Acquisition System
Manufacturer
Linear Technology Corporation
Datasheet

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lt1293DCSW/B/C
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GAUGE BRIDGE
350Ω STRAIN
KEY SPECIFICATIO S
FEATURE
TYPICAL
Software Programmable Features
Built-In Sample and Hold
Single Supply 5V or ±5V Operation
Direct 4-Wire Interface to Most MPU Serial
Ports and All MPU Parallel Ports
46.5kHz Maximum Throughput Rate
System Shutdown Output (LTC1296)
Resolution: 12 Bits
Fast Conversion Time: 12µs Max Over Temp
Low Supply Current: 6.0mA
Unipolar/Bipolar Conversion
Differential/Single Ended Inputs
MSB-First or MSB/LSB Data Sequence
Power Shutdown
THREE ADDITIONAL STRAIN GAUGE INPUTS
CAN BE ACCOMMODATED USING THE OTHER
AMPLIFIERS IN THE LT1014
S
A
PPLICATI
10k
R1
U
O
U
2N3906
12-Bit Data Acquisition System with Power Shutdown
+
1/4 LT1014
1.2M
1µF
R2
C2
5.1k
R
B
R2
1.2M
D
The LTC1293/4/6 is a family of data acquisition systems
which contain a serial I/O successive approximation A/D
converter. It uses LTCMOS
ogy to perform either 12-bit unipolar, or 11-bit plus sign
bipolar A/D conversions. The 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
LTC1293/4/6 is idle it can be powered down in applica-
tions where low power consumption is desired. The
LTC1296 includes a System Shutdown Output pin which
can be used to power down external circuitry, such as
signal conditioning circuitry prior to the input mux.
The serial I/O is designed to communicate without external
hardware to most MPU serial ports and all MPU parallel
I/O ports allowing up to eight channels of data to be
transmitted over as few as three wires.
LTCMOS
ESCRIPTIO
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
DGND
TM
is a trademark of Linear Technology Corporation
LTC1293/LTC1294/LTC1296
LTC1296
Data Acquisition System
AGND
D
REF
REF
SSO
CLK
V
OUT
D
CS
V
CC
IN
U
+
Single Chip 12-Bit
TM
switched capacitor technol-
74HC04
MPU
47µF
LTC1293 TA01
129346fs
1N4148
+5V
1

Related parts for lt1293

lt1293 Summary of contents

Page 1

... The serial I/O is designed to communicate without external hardware to most MPU serial ports and all MPU parallel I/O ports allowing up to eight channels of data to be transmitted over as few as three wires. LTCMOS trademark of Linear Technology Corporation U 12-Bit Data Acquisition System with Power Shutdown R B 5.1k 2N3906 ...

Page 2

LTC1293/LTC1294/LTC1296 BSOLUTE – Supply Voltage ( GND – Negative Supply Voltage (V ) ..................... –6V to GND Voltage Analog and Reference – Inputs ............................ (V Digital Inputs ......................................... ...

Page 3

VERTER A D ULTIPLEXER CHARACTERISTICS PARAMETER CONDITIONS Offset Error (Note 4) Linearity Error (INL) (Notes 4, 5) Gain Error (Note 4) Minimum Resolution for which No Missing Codes are Guaranteed Analog and REF Input Range (Note ...

Page 4

LTC1293/LTC1294/LTC1296 U DIGITAL A D ELECTRICAL C DC SYMBOL PARAMETER V High Level Input Voltage IH V Low Level Input Voltage IL I High Level Input Current IH I Low Level Input Current IL V High Level Output Voltage OH ...

Page 5

W U TYPICAL PERFOR A Supply Current vs Supply Voltage 10 CLK = 1MHz T = 25° SUPPLY VOLTAGE (V) LTC1293 G01 Change in Linearity vs Reference Voltage 1.25 1.00 0.75 0.50 ...

Page 6

LTC1293/LTC1294/LTC1296 W U TYPICAL PERFOR A D Delay Time vs Temperature OUT 250 200 MSB FIRST DATA 150 100 LSB FIRST DATA 50 0 – – 100 125 AMBIENT TEMPERATURE (°C) LTC1293 ...

Page 7

CTIO S LTC1293 # PIN FUNCTION DESCRIPTION 1 – 6 CH0 – CH5 Analog Inputs The analog inputs must be free of noise with respect to AGND. 7 COM Common The common pin defines the ...

Page 8

LTC1293/LTC1294/LTC1296 W BLOCK I D AGRA (Pin numbers refer to LTC1294 INPUT 15 D SHIFT IN REGISTER 1 CH0 2 CH1 3 CH2 4 ANALOG CH3 INPUT MUX 5 CH4 6 CH5 7 CH6 ...

Page 9

TEST CIRCUITS START 1 CLK D OUT Voltage Waveform for t CS 0.8V t SSO dis 2.4V SSO Voltage Waveform for for t CLK 0.8V t SSO en SSO 0.8V Voltage Waveform for D Delay Time, t ...

Page 10

LTC1293/LTC1294/LTC1296 PPLICATI S I FOR ATIO A The LTC 1293/4 data acquisition component which contains the following functional blocks: 1. 12-bit successive approximation capacitive A/D converter 2. Analog multiplexer (MUX) 3. Sample and hold (S/H) ...

Page 11

PPLICATI S I FOR ATIO Table 1a. LTC1294/6 Multiplexer Channel Selection MUX ADDRESS DIFFERENTIAL CHANNEL SELECTION SGL/ ODD SELECT DIFF SIGN – ...

Page 12

LTC1293/LTC1294/LTC1296 PPLICATI FOR ATIO OUTPUT CODE • • • 0 ...

Page 13

PPLICATI S I FOR ATIO Example 2: The same conditions as Example 1 except COM = 1V. The resulting input span is 1V ≤ ≥ 4V the resulting word is all ...

Page 14

LTC1293/LTC1294/LTC1296 PPLICATI S I FOR ATIO Example: Differential Inputs (CH4 CS CLK START SEL1 UNI ODD/ MSBF SEL1/ SEL0 DIFF SIGN HI-Z D OUT *STOPPING THE CLOCK WILL HELP REDUCE POWER CONSUMPTION. CS ...

Page 15

PPLICATI S I FOR ATIO Motorola SPI (MC68HC11) The MC68HC11 has been chosen as an example of an MPU with a dedicated serial port. This MPU transfers data MSB- first and in 8-bit increments. The D ...

Page 16

LTC1293/LTC1294/LTC1296 PPLICATI S I FOR ATIO MC68HC11 CODE LABEL MNEMONIC OPERAND COMMENTS LDAA #$50 CONFIGURATION DATA FOR SPCR STAA $1028 LOAD DATA INTO SPCR ($1028) LDAA #$1B CONFIG. DATA FOR PORT D DDR STAA $1009 LOAD ...

Page 17

PPLICATI S I FOR ATIO 8051 CODE LABEL MNEMONIC OPERAND COMMENTS SETB P1.4 CS GOES HIGH CONT MOV A,#87H DIN WORD FOR LTC1294 CLR P1.4 CS GOES LOW MOV R4,#08H LOAD COUNTER LOOP1 RLC A ROTATE ...

Page 18

LTC1293/LTC1294/LTC1296 PPLICATI S I FOR ATIO LTC1294. Figure 4 shows an example of an ideal LTC1293/ 4/6 ground plane design for a two sided board. Of course this much ground plane will not always be possible, ...

Page 19

PPLICATI FOR ATIO Source Resistance The analog inputs of the LTC1293/4/6 look like a 100pF capacitor ( series with a 500Ω resistor (R IN gets switched between (+) and (–) inputs once ...

Page 20

LTC1293/LTC1294/LTC1296 PPLICATI FOR ATIO within the minimum settling windows of 2.5µs (“+” input) and 1µs(“–” input) that occurs at the maximum clock rate of 1MHz. Figures 9 and 10 show examples of adequate and ...

Page 21

PPLICATI FOR ATIO Usually V will not be significant. For a 60Hz signal ERROR on the “–” input to generate a 0.25LSB error (300µV) with the converter running at CLK = 1MHz, its peak ...

Page 22

LTC1293/LTC1294/LTC1296 PPLICATI S I FOR ATIO a 1.25 reference. If this offset is unacceptable, it can be corrected digitally by the receiving system or by offsetting the “–” input to the LTC1293/4/6. Noise with Reduced V ...

Page 23

... As shown in Figure 20a, a 1kΩ resistor is enough to stand off ±15V (15mA for only one 80 100 channel). If more than one channel exceeds the supplies than the following guidelines can be used. Limit the LT1293 F17 current to 7mA per channel and 28mA for all channels ...

Page 24

LTC1293/LTC1294/LTC1296 PPLICATI S I FOR ATIO This means four channels can handle 7mA of input current each. Reducing CLK frequency from a maximum of 1MHz (See typical performance characteristics curves Maxi- mum CLK Frequency vs Source ...

Page 25

PPLICATI S I FOR ATIO A “Quick Look” Circuit for the LTC1294/6 Users can get a quick look at the function and timing of the LTC1294/6 by using the following simple circuit (Figure 23 ...

Page 26

LTC1293/LTC1294/LTC1296 O U TYPICAL A PPLICATI Micropower, 5000V Opto-Isolated, Multichannel,12-Bit Data Acquisition System is Accessed Once Every Two Seconds LT1027 10µF* CH0 DV CC CH1 AV CC CH2 CLK 8 CH3 CS ANALOG INPUTS CH4 D OUT 0–5V RANGE LTC1294 ...

Page 27

... Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. LTC1293/LTC1294/LTC1296 U Dimensions in inches (millimeters) unless otherwise noted ...

Page 28

... SEE NOTE (10.008 – 10.643 JMAX 110°C LT/GP 0392 10K REV 0 © LINEAR TECHNOLOGY CORPORATION 1992 0.394 – 0.419 SOL16 12/91 θ JA 150°C/W 0.394 – 0.419 SOL20 12/91 θ JA 150°C/W 129346fs ...

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