LTC2498.pdf 데이터시트 (총 30 페이지) - 파일 다운로드 LTC2498 데이타시트 다운로드

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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
wwwn.DaIntateShgeraett4eUd.cHoimgh 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 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 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/
ADCIN
VCC
REF+
IN+
24-BIT ΔΣ ADC
WITH EASY-DRIVE
IN
REF
SDI
SCK
SDO
CS
MUXOUT/
ADCIN
FO
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
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LTC2498
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltage (VCC) ................................... –0.3V to 6V
Analog Input Voltage
(CH0 to CH15, COM) ................–0.3V to (VCC + 0.3V)
Reference Input Voltage
ADCINN, ADCINP, MUXOUTP,
MUXOUTN ................................–0.3V to (VCC + 0.3V)
Digital Input Voltage......................–0.3V to (VCC + 0.3V)
Digital Output Voltage ...................–0.3V to (VCC + 0.3V)
Operating Temperature Range
www.DaLTtaCS2h4ee9t84CU.c..o..m............................................ 0°C to 70°C
LTC2498I.............................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
PIN CONFIGURATION
TOP VIEW
GND 1
NC 2
GND 3
GND 4
GND 5
GND 6
COM 7
CH0 8
CH1 9
CH2 10
CH3 11
CH4 12
38 37 36 35 34 33 32
39
13 14 15 16 17 18 19
31 GND
30 REF
29 REF+
28 VCC
27 MUXOUTN
26 ADCINN
25 ADCINP
24 MUXOUTP
23 CH15
22 CH14
21 CH13
20 CH12
UHF PACKAGE
38-LEAD (5mm × 7mm) PLASTIC QFN
TJMAX = 125°C, θJA = 34°C/W
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC2498CUHF#PBF
LTC2498CUHF#TRPBF 2498
38-Lead (5mm × 7mm) Plastic QFN
0°C to 70°C
LTC2498IUHF#PBF
LTC2498IUHF#TRPBF 2498
38-Lead (5mm × 7mm) Plastic QFN
–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/
ELECTRICAL 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 TYP MAX
UNITS
Resolution (No Missing Codes)
Integral Nonlinearity
Offset Error
Offset Error Drift
Positive Full-Scale Error
Positive Full-Scale Error Drift
Negative Full-Scale Error
0.1V ≤ VREF ≤ VCC, –FS ≤ VIN ≤ +FS (Note 5)
24
Bits
5V ≤ VCC ≤ 5.5V, VREF = 5V, VIN(CM) = 2.5V (Note 6)
2.7V ≤ VCC ≤ 5.5V, VREF = 2.5V, VIN(CM) = 1.25V (Note 6)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Note 14)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC
2.5V ≤ VREF ≤ VCC, IN+ = 0.75VREF, IN= 0.25VREF
2.5V ≤ VREF ≤ VCC, IN+ = 0.75VREF, IN= 0.25VREF
2.5V ≤ VREF ≤ VCC, IN+ = 0.25VREF, IN= 0.75VREF
l
l
l
l
2 10
1
0.5 2.5
ppm of VREF
ppm of VREF
μV
10 nV/°C
25 ppm of VREF
0.1 ppm of VREF/°C
25 ppm of VREF
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LTC2498
ELECTRICAL 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 TYP MAX
UNITS
Negative Full-Scale Error Drift
2.5V ≤ VREF ≤ VCC, IN+ = 0.25VREF, IN= 0.75VREF
0.1 ppm of VREF/°C
Total Unadjusted Error
5V ≤ VCC ≤ 5.5V, VREF = 2.5V, VIN(CM) = 1.25V
5V ≤ VCC ≤ 5.5V, VREF = 5V, VIN(CM) = 2.5V
2.7V ≤ VCC ≤ 5.5V, VREF = 2.5V, VIN(CM) = 1.25V
15 ppm of VREF
15 ppm of VREF
15 ppm of VREF
Output Noise
5.5V < VCC < 2.7V, 2.5V ≤ VREF ≤ VCC,
GND ≤ IN+ = IN≤ VCC (Note 13)
0.6 μVRMS
Internal PTAT Signal
TA = 27°C (Note 5)
27.8 28.0 28.2
mV
Internal PTAT Temperature Coefficient
93.5 μV/°C
ELECTRICALwww.DataSheet4U.com CHARACTERISTICS (2X 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 TYP MAX
UNITS
Resolution (No Missing Codes)
Integral Nonlinearity
Offset Error
Offset Error Drift
Positive Full-Scale Error
Positive Full-Scale Error Drift
Negative Full-Scale Error
Negative Full-Scale Error Drift
Output Noise
0.1V ≤ VREF ≤ VCC, –FS ≤ VIN ≤ +FS (Note 5)
5V ≤ VCC ≤ 5.5V, VREF = 5V, VIN(CM) = 2.5V (Note 6)
2.7V ≤ VCC ≤5.5V, VREF = 2.5V, VIN(CM) = 1.2V (Note 6)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Note 14)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC
2.5V ≤ VREF ≤ VCC, IN+ = 0.75VREF, IN= 0.25VREF
2.5V ≤ VREF ≤ VCC, IN+ = 0.75VREF, IN= 0.25VREF
2.5V ≤ VREF ≤ VCC, IN+ = 0.25VREF, IN= 0.75VREF
2.5V ≤ VREF ≤ VCC, IN+ = 0.25VREF, IN= 0.75VREF
5V ≤ VCC ≤ 2.5V, VREF = 5V, GND ≤ IN+ = IN≤ VCC
24 Bits
l 2 10 ppm of VREF
1 ppm of VREF
l 0.5 2
mV
100 nV/°C
l 25 ppm of VREF
0.1 ppm of VREF/°C
l 25 ppm of VREF
0.1 ppm of VREF/°C
0.85 μVRMS
CONVERTER CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 3)
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Input Common Mode Rejection DC
Input Common Mode Rejection 60Hz ±2%
Input Common Mode Rejection 50Hz ±2%
Input Normal Mode Rejection 50Hz ±2%
Input Normal Mode Rejection 60Hz ±2%
Input Normal Mode Rejection 50Hz/60Hz ±2%
Reference Common Mode Rejection DC
Power Supply Rejection DC
Power Supply Rejection, 50Hz ±2%
Power Supply Rejection, 60Hz ±2%
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Note 5)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Note 5)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Note 5)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Notes 5, 7)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Notes 5, 8)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Notes 5, 9)
2.5V ≤ VREF ≤ VCC, GND ≤ IN+ = IN≤ VCC (Note 5)
VREF = 2.5V, IN+ = IN= GND
VREF = 2.5V, IN+ = IN= GND (Notes 7, 9)
VREF = 2.5V, IN+ = IN= GND (Notes 8, 9)
l
l
l
l
l
l
l
140
140
140
110
110
87
120
120
120
140
120
120
120
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
ANALOG INPUT AND REFERENCE The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
IN+ Absolute/Common Mode IN+ Voltage
(IN+ Corresponds to the Selected Positive Input Channel)
GND – 0.3V
VCC + 0.3V
V
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LTC2498
ANALOG INPUT AND REFERENCE The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
INAbsolute/Common Mode INVoltage
(INCorresponds to the Selected Negative Input Channel)
VIN Input Differential Voltage Range (IN+ – IN)
FS Full Scale of the Differential Input (IN+ – IN)
LSB Least Significant Bit of the Output Code
REF+ Absolute/Common Mode REF+ Voltage
REFAbsolute/Common Mode REFVoltage
VREF
CS(IN+)
Reference Voltage Range (REF+ – REF)
IN+ Sampling Capacitance
wwwC.SD(aINta)Sheet4UI.NcoSmampling Capacitance
GND – 0.3V
l –FS
l 0.5VREF
l FS/224
l 0.1
l GND
l 0.1
VCC + 0.3V
+FS
VCC
REF+ – 0.1V
VCC
11
11
V
V
V
V
V
V
pF
pF
CS(VREF)
IDC_LEAK(IN+)
IDC_LEAK(IN–)
IDC_LEAK(REF+)
IDC_LEAK(REF–)
tOPEN
QIRR
VREF Sampling Capacitance
IN+ DC Leakage Current
INDC Leakage Current
REF+ DC Leakage Current
REFDC Leakage Current
MUX Break-Before-Make
MUX Off Isolation
Sleep Mode, IN+ = GND
Sleep Mode, IN= GND
Sleep Mode, REF+ = VCC
Sleep Mode, REF= GND
l
l
l
l
VIN = 2VP-P DC to 1.8MHz
–10
–10
–100
–100
11
1 10
1 10
1 100
1 100
50
120
pF
nA
nA
nA
nA
ns
dB
DIGITAL INPUTS AND DIGITAL OUTPUTS The l denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
UNITS
VIH
High Level Input Voltage (CS, FO, SDI)
2.7V ≤ VCC ≤ 5.5V
VIL
Low Level Input Voltage (CS, FO, SDI)
2.7V ≤ VCC ≤ 5.5V
l VCC – 0.5
l
V
0.5 V
VIH High Level Input Voltage (SCK)
2.7V ≤ VCC ≤ 5.5V (Notes 10, 15)
l VCC – 0.5
V
VIL Low Level Input Voltage (SCK)
2.7V ≤ VCC ≤ 5.5V (Notes 10, 15) l
IIN
Digital Input Current (CS, FO, SDI)
0V ≤ VIN ≤ VCC
l –10
0.5 V
10 μA
IIN Digital Input Current (SCK)
0V ≤ VIN ≤ VCC (Notes 10, 15)
l –10
10
CIN Digital Input Capacitance (CS, FO, SDI)
10
μA
pF
CIN Digital Input Capacitance (SCK)
(Notes 10, 17)
10 pF
VOH High Level Output Voltage (SDO)
IO = –800μA (Notes 10, 17)
l VCC – 0.5
V
VOL Low Level Output Voltage (SDO)
IO = 1.6mA (Notes 10, 17)
l
0.4 V
VOH High Level Output Voltage (SCK)
IO = –800μA
l VCC – 0.5
V
VOL Low Level Output Voltage (SCK)
IO = 1.6mA
l
0.4 V
IOZ Hi-Z Output Leakage (SDO)
l –10
10 μA
POWER REQUIREMENTS The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Note 3)
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX
UNITS
VCC Supply Voltage
ICC Supply Current
Conversion Current (Note 12)
Temperature Measurement (Note 12)
Sleep Mode (Note 12)
l 2.7
5.5
l 160 275
l 200 300
l 12
V
μA
μA
μA
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LTC2498
DIGITAL INPUTS AND DIGITAL OUTPUTS The l denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3)
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
fEOSC
tHEO
tLEO
tCONV_1
External Oscillator Frequency Range
External Oscillator High Period
External Oscillator Low Period
Conversion Time for 1x Speed Mode
tCONV_2
Conversion Time for 2x Speed Mode
www.DataSheet4U.com
fISCK Internal SCK Frequency
DISCK
fESCK
tLESCK
tHESCK
tDOUT_ISCK
Internal SCK Duty Cycle
External SCK Frequency Range
External SCK Low Period
External SCK High Period
Internal SCK 32-Bit Data Output Time
tDOUT_ESCK
t1
t2
t3
t4
External SCK 32-Bit Data Output Time
CSto SDO Low
CSto SDO High Z
CSto SCK
CSto SCK
(Note 16)
50Hz Mode
60Hz Mode
Simultaneous 50/60Hz Mode
External Oscillator
50Hz Mode
60Hz Mode
Simultaneous 50/60Hz Mode
External Oscillator
Internal Oscillator (Note 10)
External Oscillator (Notes 10, 11)
(Note 10)
(Note 10)
(Note 10)
(Note 10)
Internal Oscillator
External Oscillator
(Note 10)
Internal SCK Mode
External SCK Mode
l 10
4000
l 0.125
50
l 0.125
50
l 157.2
160.3
163.5
l 131
133.6
136.3
l 144.1
146.9
149.9
41036/fEOSC (in kHz)
l 78.7 80.3 81.9
l 65.6 66.9 68.2
l 72.2 73.6 75.1
20556/fEOSC (in kHz)
38.4
fEOSC/8
l 45
55
l 4000
l 125
l 125
l 0.81
l0
0.83
256/fEOSC (in kHz)
32/fESCK (in kHz)
0.85
200
l0
200
l0
200
l 50
kHz
μs
μs
ms
ms
ms
ms
ms
ms
ms
ms
kHz
kHz
%
kHz
ns
ns
ms
ms
ms
ns
ns
ns
ns
tKQMAX
SCKto SDO Valid
l 200 ns
tKQMIN
t5
t6
SDO Hold After SCK
SCK Set-Up Before CS
SCK Hold After CS
(Note 5)
l 15
l 50
l
ns
ns
50 ns
t7 SDI Setup Before SCK
(Note 5)
l 100
ns
t8 SDI Hold After SCK
(Note 5)
l 100
ns
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All voltage values are with respect to GND.
Note 3: VCC = 2.7V to 5.5V unless otherwise specified.
VREFCM = VREF/2, FS = 0.5VREF
where
IN+
VIN
and
= IN+
INare
IN, VIN(CM)
the selected
= (IN+ – IN)/2,
input channels.
Note 4: Use internal conversion clock or external conversion clock source
with fEOSC = 307.2kHz unless other wise specified.
Note 5: Guaranteed by design, not subject to test.
Note 6: Integral nonlinearity is defined as the deviation of a code from a
straight line passing through the actual endpoints of the transfer curve.
The deviation is measured from the center of the quantization band.
Note 7: 50Hz mode (internal oscillator) or fEOSC = 256kHz ±2% (external
oscillator).
Note 8: 60Hz mode (internal oscillator) or fEOSC = 307.2kHz ±2% (external
oscillator).
Note 9: Simultaneous 50Hz/60Hz mode (internal oscillator) or fEOSC =
280kHz ±2% (external oscillator).
Note 10: The SCK can be configured in external SCK mode or internal SCK
mode. In external SCK mode, the SCK pin is used as a digital input and the
driving clock is fESCK. In the internal SCK mode, the SCK pin is used as a
digital output and the output clock signal during the data output is fISCK.
Note 11: The external oscillator is connected to the FO pin. The external
oscillator frequency, fEOSC, is expressed in kHz.
Note 12: The converter uses its internal oscillator.
Note 13: The output noise includes the contribution of the internal
calibration operations.
Note 14: Guaranteed by design and test correlation.
Note 15: The converter is in external SCK mode of operation such that the
SCK pin is used as a digital input. The frequency of the clock signal driving
SCK during the data output is fESCK and is expressed in Hz.
Note 16: Refer to Applications Information section for performance vs
data rate graphs.
Note 17: The converter is in internal SCK mode of operation such that the
SCK pin is used as a digital output.
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