LTC2481 Datasheet, PDF (1/40 Pages) Linear Technology – 16-Bit ΔΣ ADC with Easy Drive Input Current Cancellation and I2C Interface

LTC2481
16-Bit ∆Σ ADC with Easy Drive
Input Current Cancellation and I²C Interface
FEATURES
■ _{Easy Drive Technology Enables Rail-to-Rail Inputs}
with Zero Differential Input Current
■ _{Directly Digitizes High Impedance Sensors with}
Full Accuracy
■ _{Programmable Gain from 1 to 256}
■ _{Integrated Temperature Sensor}
■ _{GND to VCC Input/Reference Common Mode Range}
■ _{2-Wire I}²_{C Interface}
■ _{Programmable 50Hz, 60Hz or Simultaneous}
50Hz/60Hz Rejection Mode
■ _{2ppm (0.25LSB) INL, No Missing Codes}
■ _{1ppm Offset and 15ppm Full-Scale Error}
■ _{Selectable 2x Speed Mode}
■ _{No Latency: Digital Filter Settles in a Single Cycle}
■ _{Single Supply 2.7V to 5.5V Operation}
■ _{Internal Oscillator}
■ _{Six Addresses Available and One Global Address for}
Synchronization
■ _{Available in a Tiny (3mm × 3mm) 10-Lead}
DFN Package
U
APPLICATIO S
■ _{Direct Sensor Digitizer}
■ _{Weight Scales}
■ _{Direct Temperature Measurement}
■ _{Strain Gauge Transducers}
■ _{Instrumentation}
■ _{Industrial Process Control}
■ _{DVMs and Meters}
DESCRIPTIO
The LTC^®2481 combines a 16-bit plus sign No Latency ∆Σ^TM
analog-to-digital converter with patented Easy Drive^TM tech-
nology and I²C digital interface. 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 LTC2481 includes on-chip programmable gain, a
temperature sensor and an oscillator. The LTC2481 can be
configured through an I²C interface to provide a program-
mable gain from 1 to 256 in 8 steps, to digitize an external
signal or internal temperature sensor, reject line frequen-
cies (50Hz, 60Hz or simultaneous 50Hz/60Hz) as well as
a 2x speed-up mode.
The LTC2481 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 LTC2481 includes an on-chip trimmed oscil-
lator eliminating the need for external crystals or oscilla-
tors. Absolute accuracy and low drift are automatically
maintained through continuous, transparent, offset and
full-scale calibration.
, LTC and LT are registered trademarks of Linear Technology Corporation.
No Latency ∆Σ and Easy Drive are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Patent Pending.
TYPICAL APPLICATIO
V_CC
1µF
10k
SENSE
10k
I_DIFF = 0
1µF
REF⁺
V_IN+
V_CC
LTC2481
V_IN–
GND
REF^–
SCL
2-WIRE
SDA I²C INTERFACE
CA0/F₀
CA1
2481 TA01
6 ADDRESSES
+FS Error vs R_SOURCE at IN⁺ and IN^–
80
V_CC = 5V
60
40
VVV^{RIINNE+–F}
=
=
=
5V
3.75V
1.25V
F_O = GND
20 ^{TA = 25°C}
0
C_IN = 1µF
–20
–40
–60
–80
1
10
100
1k
10k 100k
R_SOURCE (Ω)
2481 TA04
2481f
1