LTC2345-18 - Octal, 18-Bit, 200ksps Differential SoftSpan ADC with Wide Input Common Mode

40 Pages·2016·1.84 MB·English

by  Linear Technology Corporation

LTC2345-18
Octal, 18-Bit, 200ksps
Differential SoftSpan ADC with
Wide Input Common Mode Range
FeaTures DescripTion
n 200ksps per Channel Throughput The LTC®2345-18 is an 18-bit, low noise 8-channel si-
n Eight Simultaneous Sampling Channels multaneous sampling successive approximation register
n ±5LSB INL (Maximum, ±4.096V Range) (SAR) ADC with differential, wide common mode range
n Guaranteed 18-Bit, No Missing Codes inputs. Operating from a 5V low voltage supply and us-
n Differential, Wide Common Mode Range Inputs ing the internal reference and buffer, each channel of this
n Per-Channel SoftSpan Input Ranges: SoftSpanTM ADC can be independently configured on a
±4.096V, 0V to 4.096V, ±2.048V, 0V to 2.048V conversion-by-conversion basis to accept ±4.096, 0V
±5V, 0V to 5V, ±2.5V, 0V to 2.5V to 4.096V, ±2.048V, or 0V to 2.048V signals. Individual
n 91.8dB Single-Conversion SNR (Typical) channels may also be disabled to increase throughput on
the remaining channels.
n −113dB THD (Typical) at f = 2kHz
IN
n 102dB CMRR (Typical) at fIN = 200Hz The wide input common mode range and 102dB CMRR of
n Rail-to-Rail Input Overdrive Tolerance the LTC2345-18 analog inputs allow the ADC to directly
n Guaranteed Operation to 125°C digitize a variety of signals, simplifying signal chain design.
n Integrated Reference and Buffer (4.096V) This input signal flexibility, combined with ±5LSB INL,
n SPI CMOS (1.8V to 5V) and LVDS Serial I/O no missing codes at 18 bits, and 91.8dB SNR, makes the
n Internal Conversion Clock, No Cycle Latency LTC2345-18 an ideal choice for many applications requir-
n 81mW Power Dissipation (Typical) ing wide dynamic range.
n 48-Lead (7mm x 7mm) QFN Package
The LTC2345-18 supports pin-selectable SPI CMOS (1.8V
to 5V) and LVDS serial interfaces. Between one and eight
applicaTions
lanes of data output may be employed in CMOS mode,
allowing the user to optimize bus width and throughput.
n Programmable Logic Controllers
n Industrial Process Control L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
SoftSpan is a trademark of Linear Technology Corporation. All other trademarks are the property
n Medical Imaging of their respective owners. Protected by U.S. Patents, including 7705765, 7961132, 8319673.
Other Patents pending.
n High Speed Data Acquisition
Typical applicaTion
Integral Nonlinearity vs
5V 1.8V TO 5V
0.1µF 2.2µF 0.1µF Output Code and Channel
CMOS OR LVDS
I/O INTERFACE 2.0 ±4.096V RANGE
5VARBITRARY 5VDIFFFEURLELNYTIAL IINN00+– S/H VDD VDDLBYP OVDD LVDS/CMOPDS 11..05 FULLY DIFFERENTIAL DRIAVLEL ( CINH–A =N N–IENL+S)
S/H LTC2345-18
50VVBIPOLAR 05VVUNIPOLAR • • • SSS///HHH MUX S1A8R- BAIDTC SSSSCDD• • •CKOOKO07I INL ERROR (LSB)–00..505
S/H SDI –1.0
D0IVFFERENTIAL INPUTS0 VIN+/IN– WITH IINN77+– SS//HH REFBUF REFIN GND BUCNCSSYV SCALOMCPKLE ––21–..10531072 –65536 0 65536 131072
WIDE INPUT COMMON MODE RANGE 234518 TA01a OUTPUT CODE
EIGHT SIMULTANEOUS 47µF 0.1µF 234518 TA01b
SAMPLING CHANNELS
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LTC2345-18
absoluTe MaxiMuM raTings pin conFiguraTion
(Notes 1, 2)
TOP VIEW
Supply Voltage (VDD) ..................................................6V YP
Supply Voltage (OVDD) ................................................6V +IN7–IN7GNDGNDGNDVDDVDDGNDVDDLBCSBUSYSDI
Internal Regulated Supply Bypass (VDDLBYP) ... (Note 3) 484746454443424140393837
Analog Input Voltage
IN6– 1 36 SDO7
IN0+ to IN7+, IN6+ 2 35 SDO–/SDO6
IN0– to IN7– (Note 4) ................(–0.3V) to (VDD + 0.3V) IINN55–+ 34 3343 SSDCKOO+–/S/SDDOO54
REFIN ....................................................–0.3V to 2.8V IN4– 5 32 SCKO+/SCKO
REFBUF, CNV (Note 4) .............–0.3V to (VDD + 0.3V) IINN43+– 67 G4N9D 3310 GONVDDD
Digital Input Voltage (Note 4) .....–0.3V to (OV + 0.3V) IN3+ 8 29 SCKI–/SCKI
DD IN2– 9 28 SCKI+/SDO3
Digital Output Voltage (Note 4) ..–0.3V to (OVDD + 0.3V) IINN21+–1101 2276 SSDDII–+//SSDDOO21
Power Dissipation ..............................................500mW IN1+12 25 SDO0
Operating Temperature Range
345678901234
LTC2345C ................................................0°C to 70°C 111111122222
LTC2345I .............................................–40°C to 85°C –IN0+IN0GNDGNDGNDGNDREFINGNDREFBUFPDS/CMOSCNV
LTC2345H ..........................................–40°C to 125°C D
LV
Storage Temperature Range ..................–65°C to 150°C UK PACKAGE
48-LEAD (7mm × 7mm) PLASTIC QFN
TJMAX = 150°C, θJA = 34°C/W
EXPOSED PAD (PIN 49) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC2345CUK-18#PBF LTC2345CUK-18#TRPBF LTC2345UK-18 48-Lead (7mm × 7mm) Plastic QFN 0°C to 70°C
LTC2345IUK-18#PBF LTC2345IUK-18#TRPBF LTC2345UK-18 48-Lead (7mm × 7mm) Plastic QFN –40°C to 85°C
LTC2345HUK-18#PBF LTC2345HUK-18#TRPBF LTC2345UK-18 48-Lead (7mm × 7mm) Plastic QFN –40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/. Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
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LTC2345-18
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. (Note 5)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V + Absolute Input Range (Note 6) l 0 V V
IN DD
(IN0+ to IN7+)
V – Absolute Input Range (Note 6) l 0 V V
IN DD
(IN0– to IN7–)
V + – V – Input Differential Voltage SoftSpan 7: ±V Range (Note 6) l – V V V
IN IN REFBUF REFBUF REFBUF
Range SoftSpan 6: ±V /1.024 Range (Note 6) l – V /1.024 V /1.024 V
REFBUF REFBUF REFBUF
SoftSpan 5: 0V to V Range (Note 6) l 0 V V
REFBUF REFBUF
SoftSpan 4: 0V to V /1.024 Range (Note 6) l 0 V /1.024 V
REFBUF REFBUF
SoftSpan 3: ±0.5 • V Range (Note 6) l –0.5 • V 0.5 • V V
REFBUF REFBUF REFBUF
SoftSpan 2: ±0.5 • V /1.024 Range (Note 6) l –0.5 • V /1.024 0.5 • V /1.024 V
REFBUF REFBUF REFBUF
SoftSpan 1: 0V to 0.5 • V Range (Note 6) l 0 0.5 • V V
REFBUF REFBUF
V Input Common Mode Voltage (Note 6) l 0 V V
CM DD
Range
V + – V – Input Differential Overdrive (Note 7) l −V V V
IN IN DD DD
Tolerance
I Analog Input Leakage Current l –1 1 µA
IN
C Analog Input Capacitance Sample Mode 50 pF
IN
Hold Mode 10 pF
CMRR Input Common Mode V + = V − = 3.6V 200Hz Sine l 84 102 dB
IN IN P-P
Rejection Ratio
V CNV High Level Input Voltage l 1.3 V
IHCNV
V CNV Low Level Input Voltage l 0.5 V
ILCNV
I CNV Input Current V = 0V to V l –10 10 μA
INCNV IN DD
converTer characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. (Note 8)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Resolution l 18 Bits
No Missing Codes l 18 Bits
Transition Noise SoftSpans 7 and 6: ±4.096V and ±4V Ranges 2.3 LSB
RMS
SoftSpans 5 and 4: 0V to 4.096V and 0V to 4V Ranges 4.6 LSB
RMS
SoftSpans 3 and 2: ±2.048V and ±2V Ranges 4.6 LSB
RMS
SoftSpan 1: 0V to 2.048V Range 9.0 LSB
RMS
INL Integral Linearity Error SoftSpans 7 and 6: ±4.096V and ±4V Ranges (Note 9) l –5 ±1.5 5 LSB
SoftSpans 5 and 4: 0V to 4.096V and 0V to 4V Ranges (Note 9) l –5 ±1.5 5 LSB
SoftSpans 3 and 2: ±2.048V and ±2V Ranges (Note 9) l –6 ±1.5 6 LSB
SoftSpan 1: 0V to 2.048V Range (Note 9) l –6 ±2.0 6 LSB
DNL Differential Linearity Error (Note 10) l −0.9 ±0.5 0.9 LSB
ZSE Zero-Scale Error (Note 11) l −750 ±50 750 μV
Zero-Scale Error Drift ±2 μV/°C
FSE Full-Scale Error (Note 11) l −0.13 ±0.025 0.13 %FS
Full-Scale Error Drift ±2.5 ppm/°C
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DynaMic accuracy
The l denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at T = 25°C. A = –1dBFS. (Notes 8, 12)
A IN
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
SINAD Signal-to-(Noise + SoftSpans 7 and 6: ±4.096V and ±4V Ranges, f = 2kHz l 87.3 91.8 dB
IN
Distortion) Ratio SoftSpans 5 and 4: 0V to 4.096V and 0V to 4V Ranges, f = 2kHz l 81.4 85.7 dB
IN
SoftSpans 3 and 2: ±2.048V and ±2V Ranges, f = 2kHz l 81.5 85.9 dB
IN
SoftSpan 1: 0V to 2.048V Range, f = 2kHz l 75.7 80.1 dB
IN
SNR Signal-to-Noise Ratio SoftSpans 7 and 6: ±4.096V and ±4V Ranges, f = 2kHz l 87.6 91.8 dB
IN
SoftSpans 5 and 4: 0V to 4.096V and 0V to 4V Ranges, f = 2kHz l 81.6 85.7 dB
IN
SoftSpans 3 and 2: ±2.048V and ±2V Ranges, f = 2kHz l 81.7 85.9 dB
IN
SoftSpan 1: 0V to 2.048V Range, f = 2kHz l 75.8 80.1 dB
IN
THD Total Harmonic Distortion SoftSpans 7 and 6: ±4.096V and ±4V Ranges, f = 2kHz l –113 –99 dB
IN
SoftSpans 5 and 4: 0V to 4.096V and 0V to 4V Ranges, f = 2kHz l –108 –96 dB
IN
SoftSpans 3 and 2: ±2.048V and ±2V Ranges, f = 2kHz l –107 –97 dB
IN
SoftSpan 1: 0V to 2.048V Range, f = 2kHz l –108 –96 dB
IN
SFDR Spurious Free Dynamic SoftSpans 7 and 6: ±4.096V and ±4V Ranges, f = 2kHz l 99 114 dB
IN
Range SoftSpans 5 and 4: 0V to 4.096V and 0V to 4V Ranges, f = 2kHz l 96 109 dB
IN
SoftSpans 3 and 2: ±2.048 and ±2V Ranges, f = 2kHz l 97 108 dB
IN
SoftSpan 1: 0V to 2.048V Range, f = 2kHz l 97 108 dB
IN
Channel-to-Channel One Channel Converting 3.6V 200Hz Sine in ±2.048V Range, −107 dB
P-P
Crosstalk Crosstalk to All Other Channels
–3dB Input Bandwidth 31 MHz
Aperture Delay 1 ns
Aperture Delay Matching 150 ps
Aperture Jitter 3 ps
RMS
Transient Response Full-Scale Step, 0.005% Settling 200 ns
inTernal reFerence characTerisTics
The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T = 25°C. (Note 8)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V Internal Reference Output Voltage 2.043 2.048 2.053 V
REFIN
Internal Reference Temperature Coefficient (Note 13) l 5 20 ppm/°C
Internal Reference Line Regulation V = 4.75V to 5.25V 0.1 mV/V
DD
Internal Reference Output Impedance 20 kΩ
V REFIN Voltage Range REFIN Overdriven (Note 6) 1.25 2.2 V
REFIN
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LTC2345-18
reFerence buFFer characTerisTics
The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T = 25°C. (Note 8)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V Reference Buffer Output Voltage REFIN Overdriven, V = 2.048V l 4.091 4.096 4.101 V
REFBUF REFIN
REFBUF Voltage Range REFBUF Overdriven (Notes 6, 14) l 2.5 5 V
REFBUF Input Impedance V = 0V, Buffer Disabled 13 kΩ
REFIN
I REFBUF Load Current V = 5V, 8 Channels Enabled (Notes 14, 15) l 1.5 1.9 mA
REFBUF REFBUF
V = 5V, Acquisition Mode (Note 14) 0.39 mA
REFBUF
DigiTal inpuTs anD DigiTal ouTpuTs
The l denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at T = 25°C. (Note 8)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
CMOS Digital Inputs and Outputs
V High Level Input Voltage l 0.8 • OV V
IH DD
V Low Level Input Voltage l 0.2 • OV V
IL DD
I Digital Input Current V = 0V to OV l –10 10 μA
IN IN DD
C Digital Input Capacitance 5 pF
IN
V High Level Output Voltage I = –500μA l OV  – 0.2 V
OH OUT DD
V Low Level Output Voltage I = 500μA l 0.2 V
OL OUT
I Hi-Z Output Leakage Current V = 0V to OV l –10 10 μA
OZ OUT DD
I Output Source Current V = 0V –50 mA
SOURCE OUT
I Output Sink Current V = OV 50 mA
SINK OUT DD
LVDS Digital Inputs and Outputs
V Differential Input Voltage l 200 350 600 mV
ID
R On-Chip Input Termination CS = 0V, V = 1.2V l 80 106 130 Ω
ID ICM
Resistance CS = OV 10 MΩ
DD
V Common-Mode Input Voltage l 0.3 1.2 2.2 V
ICM
I Common-Mode Input Current V + = V – = 0V to OV l –10 10 μA
ICM IN IN DD
V Differential Output Voltage R = 100Ω Differential Termination l 275 350 425 mV
OD L
V Common-Mode Output Voltage R = 100Ω Differential Termination l 1.1 1.2 1.3 V
OCM L
I Hi-Z Output Leakage Current V = 0V to OV l –10 10 μA
OZ OUT DD
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LTC2345-18
power requireMenTs
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T = 25°C. (Note 8)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
CMOS I/O Mode
V Supply Voltage l 4.75 5.00 5.25 V
DD
OV Supply Voltage l 1.71 5.25 V
DD
I Supply Current 200ksps Sample Rate, 8 Channels Enabled l 15.3 17.6 mA
VDD
200ksps Sample Rate, 8 Channels Enabled, V = 5V (Note 14) l 13.7 15.8 mA
REFBUF
Acquisition Mode l 1.3 2.1 mA
Power Down Mode (C-Grade and I-Grade) l 65 225 μA
Power Down Mode (H-Grade) l 65 500 µA
I Supply Current 200ksps Sample Rate, 8 Channels Enabled (C = 25pF) l 1.8 2.6 mA
OVDD L
Acquisition Mode l 1 20 μA
Power Down Mode l 1 20 μA
P Power Dissipation 200ksps Sample Rate, 8 Channels Enabled l 81 95 mW
D
Acquisition Mode l 6.5 11 mW
Power Down Mode (C-Grade and I-Grade) l 0.33 1.2 mW
Power Down Mode (H-Grade) l 0.33 2.6 mW
LVDS I/O Mode
V Supply Voltage l 4.75 5.00 5.25 V
DD
OV Supply Voltage l 2.375 5.25 V
DD
I Supply Current 200ksps Sample Rate, 8 Channels Enabled l 17.9 20.6 mA
VDD
200ksps Sample Rate, 8 Channels Enabled, V = 5V (Note 14) l 16.2 18.6 mA
REFBUF
Acquisition Mode l 2.8 3.8 mA
Power Down Mode (C-Grade and I-Grade) l 65 225 μA
Power Down Mode (H-Grade) l 65 500 µA
I Supply Current 200ksps Sample Rate, 8 Channels Enabled (R = 100Ω) l 7 8.5 mA
OVDD L
Acquisition or (R = 100Ω) l 7 8.0 mA
L
Power Down Mode l 1 20 μA
P Power Dissipation 200ksps Sample Rate, 8 Channels Enabled l 107 125 mW
D
Acquisition Mode l 32 39 mW
Power Down Mode (C-Grade and I-Grade) l 0.33 1.2 mW
Power Down Mode (H-Grade) l 0.33 2.6 mW
aDc TiMing characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. (Note 8)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
f Maximum Sampling Frequency 8 Channels Enabled l 200 ksps
SMPL
7 Channels Enabled l 225 ksps
6 Channels Enabled l 266 ksps
5 Channels Enabled l 300 ksps
4 Channels Enabled l 375 ksps
3 Channels Enabled l 450 ksps
2 Channels Enabled l 625 ksps
1 Channels Enabled l 1000 ksps
t Time Between Conversions 8 Channels Enabled, f = 200ksps l 5000 ns
CYC SMPL
7 Channels Enabled, f = 225ksps l 4444 ns
SMPL
6 Channels Enabled, f = 266ksps l 3750 ns
SMPL
5 Channels Enabled, f = 300ksps l 3333 ns
SMPL
4 Channels Enabled, f = 375ksps l 2666 ns
SMPL
3 Channels Enabled, f = 450ksps l 2222 ns
SMPL
2 Channels Enabled, f = 625ksps l 1600 ns
SMPL
1 Channels Enabled, f = 1000ksps l 1000 ns
SMPL
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LTC2345-18
aDc TiMing characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. (Note 8)
A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t Conversion Time N Channels Enabled, 1 ≤ N ≤ 8 l 455 • N – 35 505 • N – 35 555 • N – 35 ns
CONV
t Acquisition Time 8 Channels Enabled, f = 200ksps l 565 975 ns
ACQ SMPL
(t = t – t – t ) 7 Channels Enabled, f = 225ksps l 564 924 ns
ACQ CYC CONV BUSYLH SMPL
6 Channels Enabled, f = 266ksps l 425 735 ns
SMPL
5 Channels Enabled, f = 300ksps l 563 823 ns
SMPL
4 Channels Enabled, f = 375ksps l 451 661 ns
SMPL
3 Channels Enabled, f = 450ksps l 562 722 ns
SMPL
2 Channels Enabled, f = 625ksps l 495 605 ns
SMPL
1 Channels Enabled, f = 1000ksps l 450 510 ns
SMPL
t CNV High Time l 40 ns
CNVH
t CNV Low Time l 420 ns
CNVL
tBUSYLH CNV↑ to BUSY Delay CL = 25pF l 30 ns
tQUIET Digital I/O Quiet Time from CNV↑ l 20 ns
t PD High Time l 40 ns
PDH
t PD Low Time l 40 ns
PDL
t REFBUF Wake-Up Time C = 47μF, C = 0.1μF 200 ms
WAKE REFBUF REFIN
CMOS I/O Mode
t SCKI Period (Notes 16, 17) l 10 ns
SCKI
t SCKI High Time l 4 ns
SCKIH
t SCKI Low Time l 4 ns
SCKIL
tSSDISCKI SDI Setup Time from SCKI↑ (Note 16) l 2 ns
tHSDISCKI SDI Hold Time from SCKI↑ (Note 16) l 1 ns
tDSDOSCKI SDO Data Valid Delay from SCKI↑ CL = 25pF (Note 16) l 7.5 ns
tHSDOSCKI SDO Remains Valid Delay from SCKI↑ CL = 25pF (Note 16) l 1.5 ns
t SDO to SCKO Skew (Note 16) l –1 0 1 ns
SKEW
tDSDOBUSYL SDO Data Valid Delay from BUSY↓ CL = 25pF (Note 16) l 0 ns
tEN Bus Enable Time After CS↓ (Note 16) l 15 ns
tDIS Bus Relinquish Time After CS↑ (Note 16) l 15 ns
LVDS I/O Mode
t SCKI Period (Note 18) l 4 ns
SCKI
t SCKI High Time (Note 18) l 1.5 ns
SCKIH
t SCKI Low Time (Note 18) l 1.5 ns
SCKIL
t SDI Setup Time from SCKI (Notes 10, 18) l 1.2 ns
SSDISCKI
t SDI Hold Time from SCKI (Notes 10, 18) l –0.2 ns
HSDISCKI
t SDO Data Valid Delay from SCKI (Notes 10, 18) l 6 ns
DSDOSCKI
t SDO Remains Valid Delay from SCKI (Notes 10, 18) l 1 ns
HSDOSCKI
t SDO to SCKO Skew (Note 10) l –0.4 0 0.4 ns
SKEW
tDSDOBUSYL SDO Data Valid Delay from BUSY↓ (Note 10) l 0 ns
tEN Bus Enable Time After CS↓ l 50 ns
tDIS Bus Relinquish Time After CS↑ l 15 ns
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aDc TiMing characTerisTics
Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 10: Guaranteed by design, not subject to test.
may cause permanent damage to the device. Exposure to any Absolute Note 11: For bipolar SoftSpan ranges 7, 6, 3, and 2, zero-scale error
Maximum Rating condition for extended periods may affect device is the offset voltage measured from –0.5LSB when the output code
reliability and lifetime. flickers between 00 0000 0000 0000 0000 and 11 1111 1111 1111 1111.
Note 2: All voltage values are with respect to ground. Full-scale error for these SoftSpan ranges is the worst-case deviation of
Note 3: V is the output of an internal voltage regulator, and should the first and last code transitions from ideal and includes the effect of
DDLBYP
only be connected to a 2.2μF ceramic capacitor to bypass the pin to GND, offset error. For unipolar SoftSpan ranges 5, 4, and 1, zero-scale error is
as described in the Pin Functions section. Do not connect this pin to any the offset voltage measured from 0.5LSB when the output code flickers
external circuitry. between 00 0000 0000 0000 0000 and 00 0000 0000 0000 0001. Full-
scale error for these SoftSpan ranges is the worst-case deviation of the
Note 4: When these pin voltages are taken below ground or above V or
DD
last code transition from ideal and includes the effect of offset error.
OV , they will be clamped by internal diodes. This product can handle
DD
currents of up to 100mA below ground or above V or OV without Note 12: All specifications in dB are referred to a full-scale input in the
DD DD
latch-up. relevant SoftSpan input range, except for crosstalk, which is referred to
the crosstalk injection signal amplitude.
Note 5: V = 5V unless otherwise specified.
DD
Note 13: Temperature coefficient is calculated by dividing the maximum
Note 6: Recommended operating conditions.
change in output voltage by the specified temperature range.
Note 7: Exceeding these limits on any channel may corrupt conversion
Note 14: When REFBUF is overdriven, the internal reference buffer must
results on other channels. Refer to Absolute Maximum Ratings section for
be disabled by setting REFIN = 0V.
pin voltage limits related to device reliability.
Note 15: I varies proportionally with sample rate and the number of
Note 8: V = 5V, OV = 2.5V, f = 200ksps, internal reference and REFBUF
DD DD SMPL
active channels.
buffer, fully differential input signal drive in SoftSpan ranges 7 and 6,
bipolar input signal drive in SoftSpan ranges 3 and 2, unipolar input signal Note 16: Parameter tested and guaranteed at OVDD = 1.71V, OVDD = 2.5V,
drive in SoftSpan ranges 5, 4 and 1, unless otherwise specified. and OVDD = 5.25V.
Note 9: Integral nonlinearity is defined as the deviation of a code from a Note 17: A tSCKI period of 10ns minimum allows a shift clock frequency of
straight line passing through the actual endpoints of the transfer curve. up to 100MHz for rising edge capture.
The deviation is measured from the center of the quantization band. Note 18: V = 1.2V, V = 350mV for LVDS differential input pairs.
ICM ID
CMOS Timings
0.8 • OVDD tWIDTH
0.2 • OVDD
tDELAY tDELAY 50% 50%
0.8 • OVDD 0.8 • OVDD 234518 F01
0.2 • OVDD 0.2 • OVDD
LVDS Timings (Differential)
+200mV
tWIDTH
–200mV
tDELAY tDELAY 0V 0V
+200mV +200mV 234518 F01b
–200mV –200mV
Figure 1. Voltage Levels for Timing Specifications
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Typical perForMance characTerisTics
T = 25°C, V  = 5V, OV  = 2.5V, Internal
A DD DD
Reference and Buffer (V  = 4.096V), f = 200ksps, unless otherwise noted.
REFBUF SMPL
Integral Nonlinearity Differential Nonlinearity Integral Nonlinearity
vs Output Code and Channel vs Output Code and Channel vs Output Code and Range
2.0 2.0 2.0
±4.096V RANGE ALL RANGES BIPOLAR DRIVE (IN– = 2.5V)
1.5 FULLY DIFFERENTIAL DRIVE (IN– = –IN+) 1.5 ALL CHANNELS 1.5 ONE CHANNEL
ALL CHANNELS
1.0 1.0 1.0 ±2.048V AND ±2V
R (LSB) 0.5 R (LSB) 0.5 R (LSB) 0.5 RANGES
RO 0 RO 0 RO 0
R R R
NL E–0.5 NL E–0.5 NL E –0.5
I D I
–1.0 –1.0 –1.0
–1.5 –1.5 –1.5
–2.0 –2.0 –2.0
–131072 –65536 0 65536 131072 0 65536 131072 196608 262144 –131072 –65536 0 65536 131072
OUTPUT CODE OUTPUT CODE OUTPUT CODE
234518 G01 234518 G02 234518 G03
Integral Nonlinearity Integral Nonlinearity Integral Nonlinearity
vs Output Code and Range vs Output Code and Range vs Output Code
4 FULLY DIFFERENTIAL DRIVE (IN– = –IN+) 4 UNIPOLAR DRIVE (IN– = 0V) 2.0 ±4.096V RANGE
ONE CHANNEL
3 ONE CHANNEL 3 1.5
0V TO 2.048V RANGE ARBITRARY DRIVE
2 ±2.048V AND ±2V 2 1.0 IN+/IN– COMMON MODE
INL ERROR (LSB) –101 ±4.096V AND ±4V RANGES INL ERROR (LSB) –110 0V TO 4.096V, AND 0V TO 4V RANGES INL ERROR (LSB)–00..505 SWEPT 0V to 5V
–2 RANGES –2 –1.0
–3 –3 –1.5 FULLY DIFFERENTIAL DRIVE (IN– = –IN+)
–4 –4 –2.0
–131072 –65536 0 65536 131072 0 65536 131072 196608 262144 –131072 –65536 0 65536 131072
OUTPUT CODE OUTPUT CODE OUTPUT CODE
234518 G04 234518 G05 234518 G06
32k Point FFT f  = 200kHz,
SMPL
DC Histogram (Zero-Scale) DC Histogram (Near Full-Scale) f  = 2kHz
IN
60000 60000 0
±4.096V RANGE ±4.096V RANGE ±4.096V RANGE
σ = 2.1 σ = 2.2 –20 FULLY DIFFERENTIAL DRIVE (IN– = –IN+)
50000 50000
–40 SNR = 92.1dB
THD = –111dB
40000 40000 FS) –60 SINAD = 92.0dB
B
d SFDR = 113dB
TS TS E ( –80
UN30000 UN30000 UD
O O T –100
C C LI
P
20000 20000 M –120
A
–140
10000 10000
–160
0 0 –180
–10 –8 –6 –4 –2 0 2 4 6 8 10 131052 131056 131060 131064 131068 131072 0 20 40 60 80 100
CODE CODE FREQUENCY (kHz)
234518 G07 234518 G08 234518 G09
234518f
9
For more information www.linear.com/LTC2345-18
LTC2345-18
Typical perForMance characTerisTics
T = 25°C, V  = 5V, OV  = 2.5V, Internal
A DD DD
Reference and Buffer (V  = 4.096V), f = 200ksps, unless otherwise noted.
REFBUF SMPL
32k Point Arbitrary Two-Tone FFT
f  = 200kHz, IN+ = –7dBFS 2kHz 32k Point FFT f = 200kHz, SNR, SINAD vs V ,
SMPL SMPL REFBUF
Sine, IN– = –7dBFS 3.1kHz Sine f  = 2kHz f  = 2kHz
IN IN
0 0 97
–20 ARB±4IT.0R9A6RVY R DARNIGVEE –20 UNIPOL0AVR T DOR 4I.V0E9 6(VIN R– A=N 0GVE) FULLY DIFFERENTIAL D±RVIVREEF (BIUNF– R= A–NING+E)
–40 SFDR = 120dB –40 SNR = 86.1dB 95
SNR = 92.1dB THD = –111dB
DE (dBFS) ––8600 DE (dBFS) ––8600 SISNFADDR = = 8 161.12ddBB AD (dBFS) 93 SNR SINAD
MPLITU ––112000 MPLITU ––112000 NR, SIN 91
A A S
–140 –140 89
–160 –160
–180 –180 87
0 20 40 60 80 100 0 20 40 60 80 100 2.5 3 3.5 4 4.5 5
FREQUENCY (KHz) FREQUENCY (kHz) REFBUF VOLTAGE (V)
234518 G10 234518 G11 234518 G12
THD, Harmonics vs V , SNR, SINAD THD, Harmonics
REFBUF
f  = 2kHz vs Input Frequency vs Input Frequency
IN
–100 102 –70
±VREFBUF RANGE ±4.096V RANGE ±4.096V RANGE
–105 FULLY DIFFERENIAL DRIVE (IN– = –IN+) FULLY DIFFERENTIAL DRIVE (IN– = –IN+) FULLY DIFFERENTIAL DRIVE (IN– = –IN+)
98 –80
S)–110 THD S)
ONICS (dBF––112105 2ND AD (dBFS) 9904 SNR ONICS (dBF–1–0900
M N SINAD M
D, HAR–125 3RD SNR, SI 86 D, HAR–110 THD
TH–130 TH 2ND
82 –120
–135
3RD
–140 78 –130
2.5 3 3.5 4 4.5 5 100 1k 10k 100k 100 1k 10k 100k
REFBUF VOLTAGE (V) FREQUENCY (Hz) FREQUENCY (Hz)
234518 G13 234518 G14 234518 G15
THD, Harmonics vs Input SNR, SINAD vs Input Level, CMRR vs Input Frequency and
Common Mode, fIN = 2kHz fIN = 2kHz Channel
–100 93.0 150
±4.096V RANGE ±4.096V RANGE ±4.096V RANGE
1VPP FULLY DIFFERENTIAL DRIVE FULLY DIFFERENTIAL DRIVE (IN– = –IN+) 140 IN+ = IN– = 3.6Vpp SINE
–105
92.8 ALL CHANNELS
HD, HARMONICS (dBFS)–––111211050 3RD THD SNR, SINAD (dBFS)9922..46 SINADSNR CMRR (dB)111101230000
T
92.2
–125
90
2ND
–130 92.0 80
0 1 2 3 4 5 –40 –30 –20 –10 0 10 100 1k 10k 100k 1M
INPUT COMMON MODE (V) INPUT LEVEL (dBFS) FREQUENCY (Hz)
234518 G16 234518 G17 234518 G18
234518f
10
For more information www.linear.com/LTC2345-18