LTC1298_15 Datasheet, PDF (1/24 Pages) Linear Technology – Micropower Sampling 12-Bit A/D Converters In S0-8 Packages

FEATURES
s _{12-Bit Resolution}
s _{8-Pin SOIC Plastic Package}
s _{Low Cost}
s _{Low Supply Current: 250µA Typ.}
s _{Auto Shutdown to 1nA Typ.}
s _{Guaranteed ±3/4LSB Max DNL}
s _{Single Supply 5V to 9V Operation}
s _{On-Chip Sample-and-Hold}
s _{60µs Conversion Time}
s _{Sampling Rates:}
12.5 ksps (LTC1286)
11.1 ksps (LTC1298)
s _{I/O Compatible with SPI, Microwire, etc.}
s _{Differential Inputs (LTC1286)}
s _{2-Channel MUX (LTC1298)}
s _{3V Versions Available: LTC1285/LTC1288}
APPLICATIONS
s _{Battery-Operated Systems}
s _{Remote Data Acquisition}
s _{Battery Monitoring}
s _{Handheld Terminal Interface}
s _{Temperature Measurement}
s _{Isolated Data Acquisition}
LTC1286/LTC1298
Micropower Sampling
12-Bit A/D Converters In
S0-8 Packages
DESCRIPTION
The LTC1286/LTC1298 are micropower, 12-bit, succes-
sive approximation sampling A/D converters. They typi-
cally draw only 250µA of supply current when converting
and automatically power down to a typical supply current
of 1nA whenever they are not performing conversions.
They are packaged in 8-pin SO packages and operate on
5V to 9V supplies. These 12-bit, switched-capacitor, suc-
cessive approximation ADCs include sample-and-holds.
The LTC1286 has a single differential analog input. The
LTC1298 offers a software selectable 2-channel MUX.
On-chip serial ports allow efficient data transfer to a wide
range of microprocessors and microcontrollers over three
wires. This, coupled with micropower consumption, makes
remote location possible and facilitates transmitting data
through isolation barriers.
These circuits 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.
TYPICAL APPLICATIONS N
25µW, S0-8 Package, 12-Bit ADC
Samples at 200Hz and Runs Off a 5V Supply
4.7µF 5V
ANALOG INPUT
0V TO 5V RANGE
1
V_REF
8
V_CC
2
7
+IN _LTC1286 CLK
3
–IN
6
D_OUT
4
GND
5
CS/SHDN
MPU
(e.g., 8051)
P1.4
P1.3
P1.2
SERIAL DATA LINK
LTC1286/98 • TA01
Supply Current vs Sample Rate
1000
T_A = 25°C
V_CC = V_REF = 5V
f_CLK = 200kHz
100
10
1
0.1k
1k
10k
100k
SAMPLE FREQUENCY (Hz)
LTC1286/98 • TA02
1