LTC2495
1
2495f
TYPICAL APPLICATION
Data Acquisition System with Temperature Compensation
FEATURES
APPLICATIONS
DESCRIPTION
16-Bit 8-/16-Channel
ΔΣ
ADC with PGA, Easy Drive
and I
2
C Interface
The LTC
2495 is a 16-channel (eight differential), 16-bit,
No Latency
ΔΣ
TM
ADC with Easy Drive technology and a
2-wire, I
2
C interface. The patented sampling scheme elimi-
nates 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 rail-to-rail input signals to be directly
digitized while maintaining exceptional DC accuracy.
The LTC2495 includes programmable gain, a high accuracy
temperature sensor, and an integrated oscillator. This device
can be configured to measure an external signal (from com-
binations of 16 analog input channels operating in single-
ended or differential modes) or its internal temperature
sensor. The integrated temperature sensor offers 1/2°C
resolution and 2°C absolute accuracy. The LTC2495 can
be configured to provide a programmable gain from 1 to
256 in 8 steps.
The LTC2495 allows a wide common mode input range
(0V to V
CC
), independent of the reference voltage. Any
combination of single-ended or differential inputs can
be selected and the first conversion, after a new channel
is selected, is valid. Access to the multiplexer output en-
ables optional external amplifiers to be shared between all
analog inputs and auto calibration continuously removes
their associated offset and drift.
■
Up to Eight Differential or 16 Single-Ended Inputs
■
Easy Drive
TM
Technology Enables Rail-to-Rail
Inputs with Zero Differential Input Current
■
Directly Digitizes High Impedance Sensors with
Full Accuracy
■
2-Wire I
2
C Interface with 27 Addresses Plus One
Global Address for Synchronization
■
600nV RMS Noise
■
Programmable Gain from 1 to 256
■
Integrated High Accuracy Temperature Sensor
■
GND to V
CC
Input/Reference Common Mode Range
■
Programmable 50Hz, 60Hz, or Simultaneous 50Hz/
60Hz Rejection Mode
■
2ppm INL, No Missing Codes
■
1ppm Offset and 15ppm Full-Scale Error
■
2x Speed/Reduced Power Mode (15Hz Using Internal
Oscillator and 80μA at 7.5Hz Output)
■
No Latency: Digital Filter Settles in a Single Cycle,
Even After a New Channel is Selected
■
Single Supply 2.7V to 5.5V Operation (0.8mW)
■
Internal Oscillator
■
Tiny 5mm
×
7mm QFN Package
■
Direct Sensor Digitizer
■
Direct Temperature Measurement
■
Instrumentation
■
Industrial Process Control
Built-In High Performance Temperature Sensor
, LT, LTC and LTM 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.
SCL
SDA
F
O
REF
+
V
CC
MUXOUT/
ADCIN
MUXOUT/
ADCIN
2.7V TO 5.5V
10
μ
F
1.7k
COM
REF
–
16-BIT
Σ
ADC
WITH EASY DRIVE
16-CHANNEL
MUX
TEMPERATURE
SENSOR
IN
+
IN
–
2495 TA01
2-WIRE
I
C INTERFACE
CH0
CH1
CH7
CH8
CH15
0.1
μ
F
OSC
TEMPERATURE (
°
C)
–55
–30
–5
A
°
C
5
4
3
2
1
–4
–3
–2
–1
0
120
95
70
45
20
2495 TA02
–5