Datasheet

LTC2484
1
2484fd
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
24-Bit ∆Σ ADC with
Easy Drive Input Current Cancellation
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 temperature sensor and
oscillator. The LTC2484 can be con gured to 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 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.
n
Easy Drive Technology Enables Rail-to-Rail Inputs
with Zero Differential Input Current
n
Directly Digitizes High Impedance Sensors with
Full Accuracy
n
600nV
RMS
Noise
n
Integrated Temperature Sensor
n
GND to V
CC
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
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
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.
LTC2484
V
REF
V
CC
V
CC
GND f
O
F
SDO
4-WIRE
SPI INTERFACE
0.1μF
10k
I
DIFF
= 0
10k
0.1μF
SCK
2484 TA01
CS
SDI
SENSE
V
IN
+
V
IN
R
SOURCE
(Ω)
1
+FS ERROR (ppm)
–20
0
20
1k
100k
2484 TA02
–40
–60
–80
10 100 10k
40
60
80
V
CC
= 5V
V
REF
= 5V
V
IN
+
= 3.75V
V
IN
= 1.25V
f
O
= GND
T
A
= 25°C
C
IN
= 1μF
+FS Error vs R
SOURCE
at IN
+
and IN

Summary of content (42 pages)