LTC2498 Datasheet, PDF (1/36 Pages) Linear Technology – 24-Bit 8-/16-Channel ΔΣ ADC with Easy Drive Input Current Cancellation

FEATURES
n _{Up to 8 Differential or 16 Single-Ended Inputs}
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 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 (15Hz Using Internal Oscillator)}
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 (0.8mW)}
n _{Internal Oscillator}
n _{Tiny QFN 5mm × 7mm Package}
APPLICATIONS
n _{Direct Sensor Digitizer}
n _{Direct Temperature Measurement}
n _{Instrumentation}
n _{Industrial Process Control}
LTC2498
24-Bit 8-/16-Channel ΔΣ
ADC with Easy Drive Input
Current Cancellation
DESCRIPTION
The LTC^®2498 is a 16-channel (8-differential) 24-bit No
Latency ΔΣ™ 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 LTC2498 includes a high accuracy temperature sensor
and an integrated oscillator. This device can be configured
to measure an external signal (from combinations of 16
analog input channels operating in single ended or dif-
ferential modes) or its internal temperature sensor. The
integrated temperature sensor offers 1/30th °C resolution
and 2°C absolute accuracy.
The LTC2498 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 enables
optional external amplifiers to be shared between all analog
inputs and auto calibration continuously removes their
associated offset and drift.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Δ∑ is a
trademark 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
REF⁺
IN⁺
SDI
24-BIT ΔΣ ADC SCK
WITH EASY-DRIVE SDO
IN^–
CS
REF^–
MUXOUT/
ADCIN
F_O
OSC
2498 TA01a
0.1μF
10μF
4-WIRE
SPI INTERFACE
Absolute Temperature Error
5
4
3
2
1
0
–1
–2
–3
–4
–5
–55 –30 –5 20 45 70
TEMPERATURE (°C)
95 120
2498 TA01b
2498fc
1