LTC2484_15 Datasheet, PDF (1/42 Pages) Linear Technology – 24-Bit ADC with Easy Drive Input Current Cancellation

LTC2484
24-Bit ∆Σ ADC with
Easy Drive Input Current Cancellation
Features
n _{Easy Drive Technology Enables Rail-to-Rail Inputs}
with Zero Differential Input Current
n _{Directly Digitizes High Impedance Sensors with}
Full Accuracy
n _{600nVRMS Noise}
n _{GND to VCC Input/Reference Common Mode Range}
n _{Programmable 50Hz, 60Hz or Simultaneous}
50Hz/60Hz Rejection Mode
n _{2ppm INL, No Missing Codes}
n _{1ppm Offset and 15ppm Total Unadjusted Error}
n _{Selectable 2× Speed Mode (15Hz Using Internal}
Oscillator)
n _{No Latency: Digital Filter Settles in a Single Cycle}
n _{Single Supply 2.7V to 5.5V Operation}
n _{Internal Oscillator}
n _{Available in a Tiny (3mm × 3mm) 10-Lead}
DFN Package
Applications
n _{Direct Sensor Digitizer}
n _{Weight Scales}
n _{Direct Temperature Measurement}
n _{Strain Gauge Transducers}
n _{Instrumentation}
n _{Industrial Process Control}
n _{DVMs and Meters}
Description
The LTC^®2484 combines a 24-bit No Latency ∆Σ™ analog-
to-digital converter with patented Easy Drive™ technology.
The patented sampling scheme eliminates dynamic input
current errors and the shortcomings of on-chip buffering
through automatic cancellation of differential input current.
This allows large external source impedances and input
signals with rail-to-rail input range to be directly digitized
while maintaining exceptional DC accuracy.
The LTC2484 includes an on-chip oscillator. The LTC2484
can be configured to reject line frequencies. 50Hz, 60Hz
or simultaneous 50Hz/60Hz line frequency rejection can
be selected as well as a 2× speed-up mode.
The LTC2484 allows a wide common mode input range
(0V to V_CC) independent of the reference voltage. The
reference can be as low as 100mV or can be tied directly
to V_CC. The LTC2484 includes an on-chip trimmed oscil-
lator, eliminating the need for external crystals or oscil-
lators. Absolute accuracy and low drift are automatically
maintained through continuous, transparent, offset and
full-scale calibration.
L, LT, LTC and LTM, Linear Technology and the Linear logo are registered trademarks and
No Latency ∆Σ and Easy Drive are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Patents pending.
Typical Application
V_CC
0.1µF
1µF
10k
SENSE
10k
I_DIFF = 0
0.1µF
V_IN+ ^VREF
V_CC
LTC2484
V_IN–
GND
f_O
SDI
SDO
SCK
CS
2484 TA01
4-WIRE
SPI INTERFACE
+FS Error vs R_SOURCE at IN⁺ and IN^–
80 _{VCC = 5V}
60
40
VVV^{RIINNE+–F}
=
=
=
5V
3.75V
1.25V
f_O = GND
20 ^{TA = 25°C}
C_IN = 1µF
0
–20
–40
–60
–80
1
10
100
1k
10k 100k
R_SOURCE (Ω)
2484 TA02
For more information www.linear.com/LTC2484
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