Document
LTC2493
Features
24-Bit 2-/4-Channel ∆∑ ADC with Easy Drive Input Current
Cancellation and I2C Interface Description
n Up to 2 Differential or 4 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 2-Wire I2C Interface with 9 Addresses Plus One
Global Address for Synchronization 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 2× Speed/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 (0.8mW) n Internal Oscillator n Tiny 4mm × 3mm DFN Package
Applications
n Direct Sensor Digitizer n Direct Temperature Measurement n Instrumentation n Industrial Process Control
The LTC®2493 is a 4-channel (2-channel differential), 24-bit, No Latency ∆∑™ ADC with Easy Drive technology and a 2-wire, I2C interface. 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 LTC2493 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 singleended or differential modes) or its internal temperature sensor. The integrated temperature sensor offers 1/30th °C resolution and 2°C absolute accuracy. The LTC2493 allows a wide common mode input range (0V to VCC), 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, 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
CH2 CH3 COM
4-CHANNEL MUX
TEMPERATURE SENSOR
VCC
0.1µF
10µF
IN+ REF+ 24-BIT ∆∑ ADC
WITH EASY-DRIVE IN– REF –
OSC
SDA SCL
CA1 CA0
fO
2493 vTA01a
1.7k 2-WIRE I2C INTERFACE
9-PIN SELECTABLE ADDRESSES
Integrated High Performance Temperature Sensor
ABSOLUTE ERROR (°C)
5 4 3 2 1 0 –1 –2 –3 –4 –5 –55 –30
–5 20 45 70 TEMPERATURE (°C)
95 120
2493 TA02
For more information www.linear.com/LTC2493
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LTC2493
Absolute Maximum Ratings
(Notes 1, 2)
Supply Voltage (VCC).................................... –0.3V to 6V Analog Input Voltage
(CH0 to REF+, REF
CH3, COM)................... –...................................
– –
0.3V 0.3V
to to
(VCC (VCC
+ +
0.3V) 0.3V)
Digital Input Voltage..................... –0.3V to (VCC + 0.3V)
Digital Output Voltage................... –0.3V to (VCC + 0.3V)
Operating Temperature Range
LTC2493C................................................. 0°C to 70°C
LTC2493I..............................................–40°C to 85°C
Storage Temperature Range...................–65°C to 150°C
Pin Configuration
fO 1 CA0 2 CA1 3 SCL 4 SDA 5 GND 6 COM 7
14 REF – 13 REF+
12 VCC 15 11 CH3
10 CH2
9 CH1
8 CH0
DE PACKAGE 14-LEAD (4mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 37°C/W EXPOSED PAD (PIN 15) IS GND, MUST BE SOLDERED TO PCB
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC2493CDE#PBF
LTC2493CDE#TRPBF
2493
14-Lead (4mm × 3mm) Plastic DFN 0°C to 70°C
LTC2493IDE#PBF
LTC2493IDE#TRPBF
2493
14-Lead (4mm × 3mm) Plastic DFN –40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
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LTC2493
E lectrical Characteristics (Normal Speed) The l denotes the specifications which
apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 3, 4)
PARAMETER
CONDITIONS
MIN.