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LTC1594L/LTC1598L
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APPLICATIO S
U
DESCRIPTIO
U
FEATURES
TYPICAL APPLICATION
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The LTC
®
1594L/LTC1598L are 3V micropower, 12-bit
sampling A/D converters that feature 4- and 8-channel
multiplexers, respectively. They typically draw only 160µA
of supply current when converting and automatically
power down to a typical supply current of 1nA between
conversions. The LTC1594L is available in a 16-pin SO
package and the LTC1598L is packaged in a 24-pin
SSOP. Both operate on a 3V supply. The 12-bit, switched-
capacitor, successive approximation ADCs include a
sample-and-hold.
On-chip serial ports allow efficient data transfer to a wide
range of microprocessors and microcontrollers over three
or four wires. This, coupled with micropower consump-
tion, makes remote location possible and facilitates trans-
mitting data through isolation barriers.
The circuit can be used in ratiometric applications or with
an external reference. The high impedance analog inputs
and the ability to operate with reduced spans (to 1.5V full
scale) allow direct connection to sensors and transducers
in many applications, eliminating the need for gain stages.
4- and 8-Channel,
3V Micropower Sampling
12-Bit Serial I/O A/D Converters
■
12-Bit Resolution on 3V Supply
■
Low Supply Current: 160µA Typ
■
Auto Shutdown to 1nA
■
Guaranteed ±3/4LSB Max DNL
■
Guaranteed 2.7V Operation
(5V Versions Available: LTC1594/LTC1598)
■
Multiplexer: 4-Channel MUX (LTC1594L)
8-Channel MUX (LTC1598L)
■
Separate MUX Output and ADC Input Pins
■
MUX and ADC May Be Controlled Separately
■
Sampling Rate: 10.5ksps
■
I/O Compatible with QSPI, SPI and MICROWIRE
TM
, etc.
■
Small Package: 16-Pin Narrow SO (LTC1594L)
24-Pin SSOP (LTC1598L)
■
Pen Screen Digitizing
■
Battery-Operated Systems
■
Remote Data Acquisition
■
Isolated Data Acquisition
■
Battery Monitoring
■
Temperature Measurement
MICROWIRE is a trademark of National Semiconductor Corporation.
, LTC and LT are registered trademarks of Linear Technology Corporation.
SAMPLE FREQUENCY (kHz)
0.1
1
SUPPLY CURRENT (µA)
10
100
1000
1 10 100
1594L/98L TA02
T
A
= 25°C
V
CC
= 2.7V
V
REF
= 2.5V
f
CLK
= 200kHz
Supply Current vs Sample Rate
12µW, 8-Channel, 12-Bit ADC Samples at 200Hz and Runs Off a 3V Supply
ANALOG
INPUTS
0V TO 3V
RANGE
1k
1µF
OPTIONAL
ADC FILTER
20
21
22
23
24
1
2
3
8
4, 9
MPU
SERIAL DATA LINK
MICROWIRE AND
SPI COMPATABLE
10
6
5, 14
7
11
12
13
18 17 16 15, 19
1µF
3V
1594L/98L TA01
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
GND
CSADC
CSMUX
CLK
D
IN
D
OUT
NC
NC
ADCIN
LTC1598L
MUXOUT
V
REF
V
CC
+
–
12-BIT
SAMPLING
ADC
8-CHANNEL
MUX