LTC1594/LTC1598
4- and 8-Channel,
Micropower Sampling
12-Bit Serial I/O A/D Converters
FEATURES
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DESCRIPTION
The LTC
®
1594/LTC1598 are micropower, 12-bit sampling
A/D converters that feature 4- and 8-channel multiplexers,
respectively. They typically draw only 320µA of supply
current when converting and automatically power down to
a typical supply current of 1nA between conversions. The
LTC1594 is available in a 16-pin SO package and the
LTC1598 is packaged in a 24-pin SSOP. Both operate on
a 5V 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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
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12-Bit Resolution
Auto Shutdown to 1nA
Low Supply Current: 320µA Typ
Guaranteed
±3/4LSB
Max DNL
Single Supply 5V Operation
(3V Versions Available: LTC1594L/LTC1598L)
Multiplexer: 4-Channel MUX (LTC1594)
8-Channel MUX (LTC1598)
Separate MUX Output and ADC Input Pins
MUX and ADC May Be Controlled Separately
Sampling Rate: 16.8ksps
I/O Compatible with QSPI, SPI and MICROWIRE
TM
, etc.
Small Package: 16-Pin Narrow SO (LTC1594)
24-Pin SSOP (LTC1598)
APPLICATIONS
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Pen Screen Digitizing
Battery-Operated Systems
Remote Data Acquisition
Isolated Data Acquisition
Battery Monitoring
Temperature Measurement
TYPICAL APPLICATION
24µW, 4-Channel, 12-Bit ADC Samples at 200Hz and Runs Off a 5V Supply
OPTIONAL
ADC FILTER
1k
1µF
18
MUXOUT
20
21
22
ANALOG
INPUTS
0V TO 5V
RANGE
23
24
1
2
3
8
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
GND
4, 9
8-CHANNEL
MUX
12-BIT
SAMPLING
ADC
CSADC
CSMUX
10
6
5, 14
7
11
12
13
1
0.1
1
10
SAMPLE FREQUENCY (kHz)
100
1594/98 TA02
5V
17
ADCIN
16
15, 19
V
REF
V
CC
1000
1µF
SERIAL DATA LINK
MICROWIRE AND
SPI COMPATABLE
T
A
= 25°C
V
CC
= 5V
V
REF
= 5V
f
CLK
= 320kHz
100
+
CLK
D
IN
D
OUT
NC
NC
1594/98 TA01
MPU
SUPPLY CURRENT (µA)
–
U
10
U
U
Supply Current vs Sample Rate
1
LINER [ LINEAR TECHNOLOGY ]
