LTC1598 Datasheet, PDF (1/12 Pages) Linear Technology – 8-Channel, Micropower Sampling 12-Bit Serial I/O A/D Converter

FEATURES
s _{12-Bit Resolution}
s _{Auto Shutdown to 1nA}
s _{Low Supply Current: 320µA Typ}
s _{Guaranteed ±3/4LSB Max DNL}
s _{Single Supply 5V Operation}
s _{8-Channel Multiplexer}
s _{Separate MUX Output and ADC Input Pins}
s _{MUX and ADC May Be Controlled Separately}
s _{Sampling Rate: 16.8ksps}
s _{I/O Compatible with SPI, MICROWIRE}^TM_{, etc.}
s _{24-Pin SSOP Package}
U
APPLICATIONS
s _{Pen Screen Digitizing}
s _{Battery-Operated Systems}
s _{Remote Data Acquisition}
s _{Isolated Data Acquisition}
s _{Battery Monitoring}
s _{Temperature Measurement}
Final Electrical Specifications
LTC1598
8-Channel, Micropower
Sampling 12-Bit Serial
I/O A/D Converter
DESCRIPTION
August 1996
The LTC^®1598 is an 8-channel, 5V micropower, 12-bit
sampling A/D converter. It typically draws only 320µA
of supply current when converting and automatically
powers down to typically 1nA between conversions. The
LTC1598 is available in a 24-pin SSOP package and
operates on a 5V supply. The 12-bit, switched-capacitor,
successive approximation ADC includes an 8-channel
MUX and 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.
TYPICAL APPLICATION
24µW, 8-Channel, 12-Bit ADC Samples at 200Hz and Runs Off a 5V Supply
OPTIONAL
ADC FILTER
1k
1µF
5V
ANALOG
INPUTS
0V TO 5V
RANGE
20 CH0
21 CH1
22 CH2
23 CH3
24 CH4
1 CH5
2 CH6
3 CH7
18
MUXOUT
8-CHANNEL
MUX
8 COM
17
ADCIN
16
15, 19
V_REF V_CC
12-BIT
+ SAMPLING
ADC
–
CS ADC
CS MUX
CLK
D_IN
D_OUT
1µF
10
6
5, 14
7
11
SERIAL DATA LINK
MICROWIRE AND
SPI COMPATABLE
MPU
GND
4, 9
12
NC
13
NC
LTC1598 • TA01
Supply Current vs Sample Rate
1000
100
T_A = 25°C
V_CC = 5V
V_REF = 5V
f_CLK = 320kHz
10
1
0.1
1
10
100
SAMPLE FREQUENCY (kHz)
1598 TA02
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.
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