LTC2494IUHF#PBF Linear Technology, LTC2494IUHF#PBF Datasheet

IC ADC 16BIT W/PGA 38-QFN

LTC2494IUHF#PBF

Manufacturer Part Number
LTC2494IUHF#PBF
Description
IC ADC 16BIT W/PGA 38-QFN
Manufacturer
Linear Technology
Datasheet

Specifications of LTC2494IUHF#PBF

Number Of Bits
16
Sampling Rate (per Second)
15
Data Interface
MICROWIRE™, Serial, SPI™
Number Of Converters
1
Power Dissipation (max)
480µW
Voltage Supply Source
Single Supply
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
38-WFQFN, Exposed Pad
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LTC2494IUHF#PBFLTC2494IUHF
Manufacturer:
LT
Quantity:
10 000
Company:
Part Number:
LTC2494IUHF#PBF
Manufacturer:
LINEAR
Quantity:
16 940
Features
applications
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n
n
n
n
n
n
n
n
n
n
n
n
n
n
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n
typical application
Up to 8 Differential or 16 Single-Ended Inputs
Easy Drive
Inputs with Zero Differential Input Current
Directly Digitizes High Impedance Sensors with
Full Accuracy
600nV RMS Noise
Programmable Gain from 1 to 256
Integrated High Accuracy Temperature Sensor
GND to V
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
Internal Oscillator
Tiny 5mm × 7mm QFN Package
Direct Sensor Digitizer
Direct Temperature Measurement
Instrumentation
Industrial Process Control
Data Acquisition System with Temperature Compensation
CC
TM
CH0
CH1
CH7
CH8
CH15
COM
Input/Reference Common Mode Range
Technology Enables Rail-to-Rail
TEMPERATURE
16-CHANNEL
SENSOR
MUX
MUXOUT/
ADCIN
MUXOUT/
ADCIN
IN
IN
+
WITH EASY-DRIVE
16-BIT
REF
REF
2.7V TO 5.5V
+
V
ADC
CC
OSC
2494 TA01a
SDO
SCK
SDI
CS
f
O
0.1µF
4-WIRE
SPI INTERFACE
16-Bit 8-/16-Channel DS ADC
Description
The LTC
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
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.
10µF
Input Current Cancellation
with PGA and Easy Drive
®
CC
2494 is a 16-channel (8-differential), 16-bit, No
), independent of the reference voltage. Any
–1
–2
–3
–4
–5
5
4
3
2
1
0
–55
Absolute Temperature Error
–30
–5
TEMPERATURE (°C)
20
45
LTC2494
70
95
2494 TA01b
120
2494fd


Related parts for LTC2494IUHF#PBF

LTC2494IUHF#PBF Summary of contents

Page 1

... 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. 2.7V TO 5.5V 0.1µ ...

Page 2

... LEAD FREE FINISH TAPE AND REEL LTC2494CUHF#PBF LTC2494CUHF#TRPBF LTC2494IUHF#PBF LTC2494IUHF#TRPBF 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: ...

Page 3

T PARAMETER CONDITIONS Resolution (No Missing Codes) 0.1V ≤ V Integral Nonlinearity 5V ≤ V 2.7V ≤ V Offset Error 2.5V ≤ V Offset Error ...

Page 4

LTC2494 analog input anD reFerence temperature range, otherwise specifications are at T SYMBOL PARAMETER + + IN Absolute/Common Mode IN + (IN Corresponds to the Selected Positive Input Channel) – – IN Absolute/Common Mode IN – (IN Corresponds to the ...

Page 5

Digital inputs anD Digital outputs full operating temperature range, otherwise specifications are at T SYMBOL PARAMETER f External Oscillator Frequency Range EOSC t External Oscillator High Period HEO t External Oscillator Low Period LEO t Conversion Time for 1x Speed ...

Page 6

LTC2494 typical perForMance characteristics Integral Nonlinearity ( 5V) CC REF REF 2.5V IN(CM GND O 1 –45°C 25°C 0 85°C –1 –2 –3 ...

Page 7

RMS Noise vs Input Differential Voltage 1 REF 0 2.5V IN(CM 25°C A 0.8 0.7 0.6 0.5 0.4 –2.5 –2 –1.5 –1 –0.5 0 0.5 1 ...

Page 8

LTC2494 typical perForMance characteristics On-Chip Oscillator Frequency vs Temperature 310 308 306 304 2.5V REF 302 GND IN(CM GND O 300 30 –45 –30 –15 0 ...

Page 9

Integral Nonlinearity (2x Speed Mode 5V 2.5V) CC REF 2.5V REF 1.25V IN(CM GND O 1 85°C 0 –45°C, 25°C –1 ...

Page 10

LTC2494 typical perForMance characteristics PSRR vs Frequency at V (2x Speed Mode 4.1V DC ±1. REF = 2.5V –20 – REF = GND + IN = GND – – GND f = GND ...

Page 11

Functions SDI (Pin 34): Serial Data Input. This pin is used to select the gain, line frequency rejection mode speed mode, temperature sensor, as well as the input channel. The serial data input is applied under ...

Page 12

LTC2494 Functional block DiagraM TEMP V SENSOR CC GND + REF – REF CH0 CH1 • • MUX • CH15 COM MUXOUTN test circuits SDO 1.69k C Hi Hi-Z OH ...

Page 13

DiagraMs Timing Diagram Using Internal SCK (SCK HIGH with CS↓ Hi-Z SDO t 3 SCK SDI SLEEP Timing Diagram Using External SCK (SCK LOW with CS↓ Hi-Z SDO t 5 SCK SDI SLEEP ...

Page 14

LTC2494 applications inForMation CONVERTER OPERATION Converter Operation Cycle The LTC2494 is a multichannel, low power, delta-sigma, analog-to-digital converter with an easy to use, 4-wire interface and automatic differential input current cancella- tion. Its operation is made up of four states ...

Page 15

This enables external RC networks and high impedance sen- sors to directly interface to the LTC2494 without external amplifiers. The remaining common mode input current is eliminated by either balancing the differential ...

Page 16

LTC2494 applications inForMation In order to achieve optimum performance external amplifier is not used, short these pins directly together (ADCINP to MUXOUTP and ADCINN to MUXOUTN) and minimize their capacitance to ground. SERIAL INTERFACE PINS The LTC2494 transmits ...

Page 17

Bit 20 (fourth output bit) is the most significant bit (MSB) of the result. This bit in conjunction with Bit 21 also pro- vides underrange and overrange indication. If both Bit 21 and Bit 20 are HIGH, the ...

Page 18

LTC2494 applications inForMation Table 2. LTC2494 Output Data Format DIFFERENTIAL INPUT VOLTAGE BIT EOC ≥ FS FS** – 1LSB 0 0.5 • FS** 0 0.5 • FS** – 1LSB ...

Page 19

Table 3. Channel Selection MUX ADDRESS ODD/ SGL SIGN ...

Page 20

LTC2494 applications inForMation Table 4. Converter Configuration SGL ODD EN2 ...

Page 21

Table 5a. Performance vs Gain in Normal Speed Mode (V GAIN 1 Input Span ±2.5 LSB 38.1 Noise Free Resolution* 65536 Gain Error 5 Offset Error 0.5 Table 5b. Performance vs Gain in 2x Speed Mode (V GAIN ...

Page 22

LTC2494 applications inForMation 1020 REF 960 SLOPE = 2.45 LSB /K 16 800 640 480 320 160 0 0 100 200 300 TEMPERATURE (K) Figure 4. Internal PTAT Digital Output vs Temperature Table ...

Page 23

CS 1 SCK (EXTERNAL) SDI DON'T CARE 1 Hi-Z SDO EOC BIT 23 BIT 22 CONVERSION SLEEP edge). The channel selection and converter configuration mode will be used for the following conversion cycle. If the input channel or ...

Page 24

LTC2494 applications inForMation CS SCK (EXTERNAL) SDI DON'T CARE SDO CONVERSION SLEEP Figure 7. External Serial Clock, Reduced Output Data Length and Valid Channel Selection SCK (EXTERNAL) SDI DON'T CARE 1 0 SDO EOC “0” BIT 23 ...

Page 25

External Serial Clock, 3-Wire I/O This timing mode uses a 3-wire serial I/O interface. The conversion result is shifted out of the device by an exter- nally generated serial clock (SCK) signal (see Figure 8 permanently ...

Page 26

LTC2494 applications inForMation The serial data output pin (SDO) is Hi-Z as long HIGH. At any time during the conversion cycle, CS may be pulled LOW in order to monitor the state of the converter. Once CS ...

Page 27

SCK (INTERNAL) SDI DON'T CARE 1 0 EOC “0” SDO BIT 23 BIT 22 CONVERSION remains unchanged. In order to program both the input channel and converter configuration, CS must go HIGH after the ...

Page 28

LTC2494 applications inForMation Whenever SCK is LOW, the LTC2494’s internal pull-up at SCK is disabled. Normally, SCK is not externally driven if the device is operating in the internal SCK timing mode. However, certain applications may require an external driver ...

Page 29

INPUT EXTERNAL MULTIPLEXER + CONNECTION I IN 100 IN + MUXOUTP – 100 – IN MUXOUTN EXTERNAL + I CONNECTION REF + REF – I REF – REF SWITCHING FREQUENCY f = 123kHz INTERNAL OSCILLATOR SW ...

Page 30

LTC2494 applications inForMation difference between V and V IN(CM) REF(CM) common mode voltage of 2.5V and an input common mode of 1.5V, the common mode input current is approximately 0.74µA (in simultaneous 50Hz/60Hz rejection mode). This common mode input current ...

Page 31

REF + V = 3.75V IN 70 – 1.25V GND 25° 0.01µF REF ...

Page 32

LTC2494 applications inForMation In addition to the reference sampling charge, the reference ESD projection diodes have a temperature dependent leak- age current. This leakage current, nominally 1nA (±10nA max) results in a small gain error. A 100Ω reference resistance will ...

Page 33

The user can expect to achieve this level of performance using the internal oscillator, as shown in Figures 23, 24 and 25. Measured values of normal mode rejection are shown superimposed over the theoretical values in all three ...

Page 34

LTC2494 applications inForMation 0 V IN(P-P) V IN(P-P) –20 (150% OF FULL SCALE) –40 –60 –80 –100 –120 105 120 135 150 165 180 195 210 225 240 INPUT FREQUENCY (Hz) Figure 26. ...

Page 35

IN(CM) REF(CM REF EXT CLOCK 85° 25°C A – ...

Page 36

LTC2494 package Description 5.50 0.05 4.10 0.05 3.00 REF 5.00 0.10 PIN 1 TOP MARK (SEE NOTE 6) 7.00 0.10 NOTE: 1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE M0-220 VARIATION WHKD 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE ...

Page 37

... Revised Typical Application drawing Added Note 18 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. LTC2494 ...

Page 38

... Pin Compatible with LTC2494/LTC2449/LTC2498 Pin Compatible with LTC2494/LTC2496/LTC2449 www.linear.com ● SDI ΔΣ ADC SCK WITH EASY DRIVE SDO INPUTS CS 0.1µF 0.1µF 2494 TA02 Noise, 2ppm INL Noise RMS LT 0710 REV D • PRINTED IN USA  LINEAR TECHNOLOGY CORPORATION 2007 2494fd ...

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