LTC2494_15 Datasheet, PDF (1/38 Pages) Linear Technology – 16-Bit 8-/16-Channel ADC with PGA and Easy Drive Input Current Cancellation

Features
n _{Up to 8 Differential or 16 Single-Ended Inputs}
n _{Easy Drive}^TM _{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 _{Programmable Gain from 1 to 256}
n _{Integrated High Accuracy Temperature Sensor}
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 Full-Scale Error}
n _{2x Speed Mode/Reduced Power Mode (15Hz Using}
Internal Oscillator and 80µA at 7.5Hz Output)
n _{No Latency: Digital Filter Settles in a Single Cycle,}
Even After a New Channel Is Selected
n _{Single-Supply 2.7V to 5.5V Operation}
n _{Internal Oscillator}
n _{Tiny 5mm × 7mm QFN Package}
Applications
n _{Direct Sensor Digitizer}
n _{Direct Temperature Measurement}
n _{Instrumentation}
n _{Industrial Process Control}
LTC2494
16-Bit 8-/16-Channel DS ADC
with PGA and Easy Drive
Input Current Cancellation
Description
The LTC^®2494 is a 16-channel (8-differential), 16-bit, No
Latency DS™ ADC with Easy Drive technology. The pat-
ented 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 rail-to-rail
input signals to be directly digitized while maintaining
exceptional DC accuracy.
The LTC2494 includes programmable gain, a high accu-
racy temperature sensor and an integrated oscillator. This
device can be configured to measure an external signal
(from combinations of 16 analog input channels operat-
ing 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
LTC2494 can be configured to provide a programmable
gain from 1 to 256 in 8 steps.
The LTC2494 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.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No Latency ∆∑ and Easy Drive are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
Typical Application
Data Acquisition System with Temperature Compensation
2.7V TO 5.5V
CH0
CH1
••
•
CH7
CH8
•
••
CH15
COM
16-CHANNEL
MUX
TEMPERATURE
SENSOR
MUXOUT/
V_CC
ADCIN
IN⁺
REF⁺
SDI
16-BIT ∆Σ ADC ^SCK
WITH EASY-DRIVE SDO
IN^–
CS
REF^–
MUXOUT/
ADCIN
f_O
OSC
2494 TA01a
0.1µF
10µF
4-WIRE
SPI INTERFACE
For more information www.linear.com/LTC2494
Absolute Temperature Error
5
4
3
2
1
0
–1
–2
–3
–4
–5
–55 –30
–5 20 45 70
TEMPERATURE (°C)
95 120
2494 TA01b
2494fe
1