LTC2492 Datasheet, PDF (1/36 Pages) Linear Technology – 24-Bit 2-/4-Channel ΔΣ ADC with Easy Drive Input Current Cancellation

FEATURES
■ _{Up to 2 Differential or 4 Single-Ended Inputs}
■ _{Easy Drive Technology Enables Rail-to-Rail Inputs}
with Zero Differential Input Current
■ _{Directly Digitizes High Impedance Sensors with}
Full Accuracy
■ _{600nV RMS Noise}
■ _{Integrated High Accuracy Temperature Sensor}
■ _{GND to VCC 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 Mode/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 DFN 4mm × 3mm Package}
APPLICATIONS
■ _{Direct Sensor Digitizer}
■ _{Direct Temperature Measurement}
■ _{Instrumentation}
■ _{Industrial Process Control}
LTC2492
24-Bit 2-/4-Channel ΔΣ
ADC with Easy Drive Input
Current Cancellation
DESCRIPTION
The LTC^®2492 is a 4-channel (2-channel differential),
24-bit, No Latency Δ∑™ ADC with 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 rail-to-
rail input signals to be directly digitized while maintaining
exceptional DC accuracy.
The LTC2492 includes a high accuracy temperature sensor
and an integrated oscillator. This device can be configured
to measure an external signal (from combinations of
4 analog input channels operating in single-ended or
differential modes) or its internal temperature sensor. It
can be programmed to reject line frequencies of 50Hz,
60Hz, or simultaneous 50Hz/60Hz and configured to double
its output rate. The integrated temperature sensor offers
1/30th °C resolution and 2°C absolute accuracy.
The LTC2492 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
selection is valid.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
No Latency Δ∑ 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
4-CHANNEL
MUX
CH2
CH3
COM
TEMPERATURE
SENSOR
V_CC
REF⁺
IN⁺
SDI
24-BIT Δ∑ ADC SCK
WITH EASY-DRIVE SDO
IN^–
CS
REF ^–
F_O
OSC
2492 TA01a
10μF
0.1μF
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
2492 TA01b
2492fb
1