LTC2480_1 Datasheet, PDF (1/42 Pages) Linear Technology – 16-Bit ΔΣ ADC with Easy Drive Input Current Cancellation

LTC2480
16-Bit ΔΣ 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 _{Programmable Gain from 1 to 256}
n _{Integrated Temperature Sensor}
n _{GND to VCC Input/Reference Common Mode Range}
n _{Programmable 50Hz, 60Hz or Simultaneous}
50Hz/60Hz Rejection Mode
n _{2ppm (0.25LSB) INL, No Missing Codes}
n _{1ppm Offset and 15ppm Full-Scale Error}
n _{Selectable 2x 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 and 10-Lead MSOP 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^®2480 combines a 16-bit plus sign No Latency
ΔΣ™ 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 LTC2480 includes on-chip programmable gain, a
temperature sensor and an oscillator. The LTC2480 can
be configured to provide a programmable gain from 1
to 256 in 8 steps, measure an external signal or internal
temperature sensor and reject line frequencies. 50Hz, 60Hz
or simultaneous 50Hz/60Hz line frequency rejection can
be selected as well as a 2x speed-up mode.
The LTC2480 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 LTC2480 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 ΔΣ 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
1μF
10k
SENSE
10k
I_DIFF = 0
1μF
V_IN+ ^VREF
V_CC
LTC2480
V_IN–
GND
f_O
SDI
SDO
SCK
CS
2480 TA01
4-WIRE
SPI INTERFACE
+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)
2480 TA04
2480fc
1