LTC2367-18 18-Bit, 500ksps, PseudoDifferential Unipolar SAR ADC with 97dB SNR FEATURES DESCRIPTION 500ksps Throughput Rate 2.5LSB INL (Max) n Guaranteed 18-Bit No Missing Codes n Low Power: 6.8mW at 500ksps, 6.8W at 500sps n 97dB SNR (Typ) at f = 2kHz IN n-120dB THD (Typ) at f = 2kHz IN n Guaranteed Operation to 125C n 2.5V Supply n Pseudo-Differential Unipolar Input Range: 0V to V REF nV Input Range from 2.5V to 5.1V REF n No Pipeline Delay, No Cycle Latency n 1.8V to 5V I/O Voltages n SPI-Compatible Serial I/O with Daisy-Chain Mode n Internal Conversion Clock n 16-Lead MSOP and 4mm x 3mm DFN Packages The LTC(R)2367-18 is a low noise, low power, high speed 18-bit successive approximation register (SAR) ADC. Operating from a 2.5V supply, the LTC2367-18 has a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V. The LTC2367-18 consumes only 6.8mW and achieves 2.5LSB INL maximum, no missing codes at 18 bits with 97dB SNR. n n The LTC2367-18 has a high speed SPI-compatible serial interface that supports 1.8V, 2.5V, 3.3V and 5V logic while also featuring a daisy-chain mode. The fast 500ksps throughput with no cycle latency makes the LTC2367-18 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2367-18 automatically powers down between conversions, leading to reduced power dissipation that scales with the sampling rate. APPLICATIONS 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 of their respective owners. Protected by U.S. Patents, including 7705765. Medical Imaging n High Speed Data Acquisition n Portable or Compact Instrumentation n Industrial Process Control n Low Power Battery-Operated Instrumentation nATE n TYPICAL APPLICATION 32k Point FFT fS = 500ksps, fIN = 2kHz 2.5V 0 1.8V TO 5V SNR = 97.2dB THD = -120dB SINAD = 97.1dB SFDR = 122dB -20 VREF 0V + LT(R)6202 - VDD 10 0.1F OVDD IN+ LTC2367-18 10nF IN- REF 2.5V TO 5.1V GND CHAIN RDL/SDI SDO SCK BUSY CNV 236718 TA01a 47F (X5R, 0805 SIZE) -40 SAMPLE CLOCK AMPLITUDE (dBFS) 10F -60 -80 -100 -120 -140 -160 -180 0 50 100 150 FREQUENCY (kHz) 200 250 236718 TA01b 236718f 1 LTC2367-18 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) Supply Voltage (VDD)................................................2.8V Supply Voltage (OVDD).................................................6V Reference Input (REF)..................................................6V Analog Input Voltage (Note 3) IN+, IN-..........................(GND - 0.3V) to (REF + 0.3V) Digital Input Voltage (Note 3)........................... (GND - 0.3V) to (OVDD + 0.3V) Digital Output Voltage (Note 3)........................... (GND - 0.3V) to (OVDD + 0.3V) Power Dissipation............................................... 500mW Operating Temperature Range LTC2367C................................................. 0C to 70C LTC2367I..............................................-40C to 85C LTC2367H........................................... -40C to 125C Storage Temperature Range................... -65C to 150C PIN CONFIGURATION TOP VIEW CHAIN 1 VDD 2 GND 3 + 4 IN- 5 GND 6 REF 7 REF 8 IN 16 GND 15 OVDD 17 GND TOP VIEW CHAIN VDD GND IN+ IN- GND REF REF 14 SDO 13 SCK 12 RDL/SDI 11 BUSY 10 GND 9 CNV 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 GND OVDD SDO SCK RDL/SDI BUSY GND CNV MS PACKAGE 16-LEAD PLASTIC MSOP TJMAX = 150C, JA = 110C/W DE PACKAGE 16-LEAD (4mm x 3mm) PLASTIC DFN TJMAX = 150C, JA = 40C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC2367CMS-18#PBF LTC2367CMS-18#TRPBF 236718 16-Lead Plastic MSOP 0C to 70C LTC2367IMS-18#PBF LTC2367IMS-18#TRPBF 236718 16-Lead Plastic MSOP -40C to 85C LTC2367HMS-18#PBF LTC2367HMS-18#TRPBF 236718 16-Lead Plastic MSOP -40C to 125C LTC2367CDE-18#PBF LTC2367CDE-18#TRPBF 23678 16-Lead (4mm x 3mm) Plastic DFN 0C to 70C LTC2367IDE-18#PBF LTC2367IDE-18#TRPBF 23678 16-Lead (4mm x 3mm) Plastic DFN -40C to 85C 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/ 236718f 2 LTC2367-18 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 4) SYMBOL PARAMETER CONDITIONS VIN+ Absolute Input Range (IN+) MIN TYP MAX UNITS (Note 5) l -0.1 VIN - Absolute Input Range (IN-) (Note 5) l VIN+ - VIN- Input Differential Voltage Range VIN = VIN+ - VIN- l IIN Analog Input Leakage Current CIN Analog Input Capacitance Sample Mode Hold Mode 45 5 pF pF CMRR Input Common Mode Rejection Ratio fIN = 250kHz 80 dB VREF + 0.1 V -0.1 0.1 V 0 VREF V 1 A l CONVERTER CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 4) SYMBOL PARAMETER CONDITIONS MIN MAX UNITS Resolution l 18 Bits No Missing Codes l 18 Bits l -2.5 0.5 2.5 LSB l -0.5 0.1 0.5 LSB l -11 0 11 Transition Noise INL Integral Linearity Error DNL Differential Linearity Error ZSE Zero-Scale Error 1.3 (Note 6) (Note 7) Zero-Scale Error Drift FSE TYP Full-Scale Error LSBRMS 0.02 (Note 7) l -50 Full-Scale Error Drift 7 LSB LSB/C 50 0.15 LSB ppm/C DYNAMIC ACCURACY l denotes the specifications which apply over the full operating temperature range, The otherwise specifications are at TA = 25C and AIN = -1dBFS. (Notes 4, 8) SYMBOL PARAMETER CONDITIONS MIN TYP SINAD Signal-to-(Noise + Distortion) Ratio fIN = 2kHz, VREF = 5V l 93.8 97 dB fIN = 2kHz, VREF = 5V, (H-Grade) l 93.3 97 dB SNR Signal-to-Noise Ratio fIN = 2kHz, VREF = 5V fIN = 2kHz, VREF = 2.5V l l 94.3 88.5 97 91.5 dB dB fIN = 2kHz, VREF = 5V, (H-Grade) fIN = 2kHz, VREF = 2.5V, (H-Grade) l l 93.8 88 97 91.5 dB dB THD Total Harmonic Distortion fIN = 2kHz, VREF = 5V fIN = 2kHz, VREF = 2.5V l l SFDR Spurious Free Dynamic Range fIN = 2kHz, VREF = 5V l -120 -119 -103 -103 UNITS dB dB 122 dB -3dB Input Bandwidth 34 MHz Aperture Delay 500 ps 4 ps 1.46 s Aperture Jitter Transient Response Full-Scale Step 104 MAX 236718f 3 LTC2367-18 REFERENCE INPUT The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 4) SYMBOL PARAMETER CONDITIONS VREF Reference Voltage (Note 5) l MIN IREF Reference Input Current (Note 9) l TYP 2.5 0.24 MAX UNITS 5.1 V 0.32 mA DIGITAL INPUTS AND DIGITAL OUTPUTS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 4) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VIH High Level Input Voltage l VIL Low Level Input Voltage l IIN Digital Input Current CIN Digital Input Capacitance VOH High Level Output Voltage IO = -500A l VOL Low Level Output Voltage IO = 500A l IOZ Hi-Z Output Leakage Current VOUT = 0V to OVDD l ISOURCE Output Source Current VOUT = 0V -10 mA ISINK Output Sink Current VOUT = OVDD 10 mA VIN = 0V to OVDD 0.8 * OVDD V -10 l 0.2 * OVDD V 10 A 5 pF OVDD - 0.2 V 0.2 -10 V 10 A POWER REQUIREMENTS l denotes the specifications which apply over the full operating temperature The range, otherwise specifications are at TA = 25C. (Note 4) SYMBOL PARAMETER CONDITIONS VDD Supply Voltage OVDD Supply Voltage IVDD IOVDD IPD IPD Supply Current Supply Current Power Down Mode Power Down Mode 500ksps Sample Rate 500ksps Sample Rate (CL = 20pF) Conversion Done (IVDD + IOVDD + IREF, VREF > 2V) Conversion Done (IVDD + IOVDD + IREF, VREF > 2V, H-Grade) PD Power Dissipation Power Down Mode Power Down Mode 500ksps Sample Rate Conversion Done (IVDD + IOVDD + IREF, VREF > 2V) Conversion Done (IVDD + IOVDD + IREF, VREF > 2V, H-Grade) MIN TYP MAX UNITS l 2.375 2.5 2.625 V l 1.71 l l l 2.7 0.1 0.9 0.9 6.75 2.25 2.25 5.25 V 3.2 90 140 mA mA A A 8 225 315 mW W W ADC TIMING CHARACTERISTICS l denotes the specifications which apply over the full operating The temperature range, otherwise specifications are at TA = 25C. (Note 4) SYMBOL PARAMETER fSMPL Maximum Sampling Frequency l tCONV Conversion Time l 1 tACQ Acquisition Time l 1.460 tHOLD Maximum Time Between Acquisitions l tCYC Time Between Conversions l 2 s tCNVH CNV High Time l 20 ns tBUSYLH CNV to BUSY Delay CL = 20pF l tCNVL Minimum Low Time for CNV (Note 11) l 20 ns SCK Quiet Time from CNV (Note 10) l 20 ns tQUIET CONDITIONS tACQ = tCYC - tHOLD (Note 10) MIN TYP MAX UNITS 500 ksps 1.5 s 540 ns s 13 ns 236718f 4 LTC2367-18 ADC TIMING CHARACTERISTICS l denotes the specifications which apply over the full operating The temperature range, otherwise specifications are at TA = 25C. (Note 4) SYMBOL PARAMETER CONDITIONS tSCK SCK Period (Notes 11, 12) tSCKH tSCKL tSSDISCK SDI Setup Time From SCK tHSDISCK MIN TYP MAX UNITS l 10 ns SCK High Time l 4 ns SCK Low Time l 4 ns (Note 11) l 4 ns SDI Hold Time From SCK (Note 11) l 1 ns 13.5 tSCKCH SCK Period in Chain Mode tSCKCH = tSSDISCK + tDSDO (Note 11) l tDSDO SDO Data Valid Delay from SCK CL = 20pF (Note 11) l tHSDO SDO Data Remains Valid Delay from SCK CL = 20pF (Note 10) l tDSDOBUSYL SDO Data Valid Delay from BUSY CL = 20pF (Note 10) l 5 ns tEN Bus Enable Time After RDL (Note 11) l 16 ns tDIS Bus Relinquish Time After RDL (Note 11) l 13 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 effect device reliability and lifetime. Note 2: All voltage values are with respect to ground. Note 3: When these pin voltages are taken below ground or above REF or OVDD, they will be clamped by internal diodes. This product can handle input currents up to 100mA below ground or above REF or OVDD without latch-up. Note 4: VDD = 2.5V, OVDD = 2.5V, REF = 5V, fSMPL = 500kHz. Note 5: Recommended operating conditions. 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. ns 9.5 1 ns ns Note 7: Zero-scale error is the offset voltage measured from 0.5LSB when the output code flickers between 00 0000 0000 0000 0000 and 00 0000 0000 0000 0001. Full-scale error is the deviation of the last code transition from ideal and includes the effect of offset error. Note 8: All specifications in dB are referred to a full-scale 5V input with a 5V reference voltage. Note 9: fSMPL = 500kHz, IREF varies proportionately with sample rate. Note 10: Guaranteed by design, not subject to test. Note 11: Parameter tested and guaranteed at OVDD = 1.71V, OVDD = 2.5V and OVDD = 5.25V. Note 12: tSCK of 10ns maximum allows a shift clock frequency up to 100MHz for rising capture. 0.8*OVDD tWIDTH 0.2*OVDD tDELAY tDELAY 0.8*OVDD 0.8*OVDD 0.2*OVDD 0.2*OVDD 50% 50% 236718 F01 Figure 1. Voltage Levels for Timing Specifications 236718f 5 LTC2367-18 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25C, VDD = 2.5V, OVDD = 2.5V, REF = 5V, fSMPL = 500ksps, unless otherwise noted. Integral Nonlinearity vs Output Code Differential Nonlinearity vs Output Code 0.5 40000 1.5 0.4 35000 0.3 0.5 0.0 -0.5 -1.0 0.0 -0.1 10000 5000 -0.4 65536 131072 196608 OUTPUT CODE -0.5 262144 0 65536 131072 196608 OUTPUT CODE 0 236718 G02 -60 -70 95 SNR -60 -80 -100 -120 -140 90 SINAD 85 80 75 -160 -80 -90 THD -100 2ND -110 3RD -120 -130 -140 -150 0 50 100 150 FREQUENCY (kHz) 200 70 250 0 50 25 SNR, SINAD vs Reference Voltage, fIN = 2kHz -100 SNR 96 SNR, SINAD (dBFS) 97.0 96.5 96.0 SINAD 95 94 93 92 95.5 91 -30 -20 -10 INPUT LEVEL (dB) 0 236718 G07 50 75 100 125 150 175 200 FREQUENCY (kHz) 90 2.5 THD, Harmonics vs Reference Voltage, fIN = 2kHz -105 97 SNR SINAD 25 236718 G06 98 97.5 0 236718 G05 SNR, SINAD vs Input level, fIN = 2kHz 95.0 -40 -160 75 100 125 150 175 200 FREQUENCY (kHz) 236718 G04 SNR, SINAD (dBFS) THD, Harmonics vs Input Frequency 100 SNR, SINAD (dBFS) AMPLITUDE (dBFS) -40 236718 G03 SNR, SINAD vs Input Frequency SNR = 97.2dB THD = -120dB SINAD = 97.1dB SFDR = 122dB -20 0 131067 131069 131071 131073 131075 131077 CODE 262144 HARMONICS, THD (dBFS) 0 32k Point FFT fS = 500ksps, fIN = 2kHz 98.0 20000 15000 -0.2 236718 G01 -180 25000 HARMONICS, THD (dBFS) -2.0 0.1 -0.3 -1.5 = 1.3 30000 0.2 COUNTS DNL ERROR (LSB) 1.0 INL ERROR (LSB) DC Histogram 2.0 -110 -115 THD -120 2ND -125 -130 -135 3RD -140 -145 3 3.5 4 4.5 REFERENCE VOLTAGE (V) 5 236718 G08 -150 2.5 3 4 4.5 3.5 REFERENCE VOLTAGE (V) 5 236718 G09 236718f 6 LTC2367-18 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25C, VDD = 2.5V, OVDD = 2.5V, REF = 5V, fSMPL = 500ksps, unless otherwise noted. THD, Harmonics vs Temperature, fIN = 2kHz 99.0 -110 98.5 -115 THD -120 2ND 97.5 SNR SINAD 97.0 96.5 96.0 -125 -130 3RD -135 95.0 -55 -35 -15 5 25 45 65 85 105 125 TEMPERATURE (C) -145 -55 -35 -15 Full-Scale Error vs Temperature -0.5 MIN INL Supply Current vs Temperature Offset Error vs Temperature 3.0 IVDD POWER SUPPLY CURRENT (mA) 8 6 OFFSET ERROR (LSB) 10 5 0 -5 -10 4 2 0 -2 -4 -6 -15 -8 -20 -55 -35 -15 -10 -55 -35 -15 5 25 45 65 85 105 125 TEMPERATURE (C) 2.5 2.0 1.5 1.0 0.5 IREF 0 -55 -35 -15 5 25 45 65 85 105 125 TEMPERATURE (C) IOVDD 5 25 45 65 85 105 125 TEMPERATURE (C) 236718 G15 236718 G14 236718 G13 Shutdown Current vs Temperature Reference Current vs Reference Voltage CMRR vs Input Frequency 100 IVDD + IOVDD + IREF 0.3 30 REFERENCE CURRENT (mA) 95 35 CMRR (dB) 90 25 20 15 85 80 10 75 5 0 -55 -35 -15 5 25 45 65 85 105 125 TEMPERATURE (C) 236718 G12 10 15 FULL-SCALE ERROR (LSB) MIN DNL 236718 G11 20 POWER-DOWN CURRENT (A) MAX DNL 0 -1.0 -55 -35 -15 5 25 45 65 85 105 125 TEMPERATURE (C) 236718 G10 40 MAX INL 0.5 -140 95.5 45 INL/DNL vs Temperature 1.0 INL/DNL ERROR (LSB) 98.0 HARMONICS, THD (dBFS) SNR, SINAD (dBFS) SNR, SINAD vs Temperature, fIN = 2kHz 5 25 45 65 85 105 125 TEMPERATURE (C) 236718 G16 70 0 50 100 150 FREQUENCY (kHz) 200 250 236718 G17 0.2 0.1 0 2.5 3 4.5 4 3.5 REFERENCE VOLTAGE (V) 5 236718 G18 236718f 7 LTC2367-18 PIN FUNCTIONS CHAIN (Pin 1): Chain Mode Selector Pin. When low, the LTC2367-18 operates in normal mode and the RDL/SDI input pin functions to enable or disable SDO. When high, the LTC2367-18 operates in chain mode and the RDL/SDI pin functions as SDI, the daisy-chain serial data input. Logic levels are determined by OVDD. VDD (Pin 2): 2.5V Power Supply. The range of VDD is 2.375V to 2.625V. Bypass VDD to GND with a 10F ceramic capacitor. GND (Pins 3, 6, 10 and 16): Ground. IN+ (Pin 4): Analog Input. IN+ operates differential with respect to IN- with an IN+-IN- range of 0V to VREF. IN- (Pin 5): Analog Ground Sense. IN- has an input range of 100mV with respect to GND and must be tied to the ground plane or a remote ground sense. REF (Pins 7, 8): Reference Inputs. The range of REF is 2.5V to 5.1V. This pin is referred to the GND pin and should be decoupled closely to the pin with a 47F ceramic capacitor (X5R, 0805 size). CNV (Pin 9): Convert Input. A rising edge on this input powers up the part and initiates a new conversion. Logic levels are determined by OVDD. BUSY (Pin 11): BUSY Indicator. Goes high at the start of a new conversion and returns low when the conversion has finished. Logic levels are determined by OVDD. RDL/SDI (Pin 12): When CHAIN is low, the part is in normal mode and the pin is treated as a bus enabling input. When CHAIN is high, the part is in chain mode and the pin is treated as a serial data input pin where data from another ADC in the daisy chain is input. Logic levels are determined by OVDD. SCK (Pin 13): Serial Data Clock Input. When SDO is enabled, the conversion result or daisy-chain data from another ADC is shifted out on the rising edges of this clock MSB first. Logic levels are determined by OVDD. SDO (Pin 14): Serial Data Output. The conversion result or daisy-chain data is output on this pin on each rising edge of SCK MSB first. The output data is in straight binary format. Logic levels are determined by OVDD. OVDD (Pin 15): I/O Interface Digital Power. The range of OVDD is 1.71V to 5.25V. This supply is nominally set to the same supply as the host interface (1.8V, 2.5V, 3.3V, or 5V). Bypass OVDD to GND with a 0.1F capacitor. GND (Exposed Pad Pin 17, DFN Package Only): Ground. Exposed pad must be soldered directly to the ground plane. 236718f 8 LTC2367-18 FUNCTIONAL BLOCK DIAGRAM VDD = 2.5V REF = 5V IN+ + 18-BIT SAMPLING ADC IN- - OVDD = 1.8V to 5V SPI PORT CHAIN SDO RDL/SDI SCK CNV CONTROL LOGIC BUSY GND 236718 BD TIMING DIAGRAM Conversion Timing Using the Serial Interface CHAIN, RDL/SDI = 0 CNV CONVERT BUSY HOLD POWER-DOWN ACQUIRE SCK D17 D16 D15 SDO D2 D1 D0 236718 TD01 236718f 9 LTC2367-18 APPLICATIONS INFORMATION OVERVIEW Fast 500ksps throughput with no cycle latency makes the LTC2367-18 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2367-18 dissipates only 6.8mW at 500ksps, while an auto power-down feature is provided to further reduce power dissipation during inactive periods. CONVERTER OPERATION The LTC2367-18 operates in two phases. During the acquisition phase, the charge redistribution capacitor D/A converter (CDAC) is connected to the IN+ and IN- pins to sample the pseudo-differential analog input voltage. A rising edge on the CNV pin initiates a conversion. During the conversion phase, the 18-bit CDAC is sequenced through a successive approximation algorithm, effectively comparing the sampled input with binary-weighted fractions of the reference voltage (e.g. VREF/2, VREF/4 ... VREF/262144) using the differential comparator. At the end of conversion, the CDAC output approximates the sampled analog input. The ADC control logic then prepares the 18-bit digital output code for serial transfer. TRANSFER FUNCTION The LTC2367-18 digitizes the full-scale voltage of REF into 218 levels, resulting in an LSB size of 19V with REF = 5V. The ideal transfer function is shown in Figure2. The output data is in straight binary format. 1LSB = FS/262144 111...110 111...101 OUTPUT CODE The LTC2367-18 is a low noise, low power, high speed 18-bit successive approximation register (SAR) ADC. Operating from a single 2.5V supply, the LTC2367-18 supports a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V, making it ideal for high performance applications which require a wide dynamic range. The LTC2367-18 achieves 2.5LSB INL max, no missing codes at 18 bits and 97dB SNR. 111...111 111...100 000...011 UNIPOLAR ZERO 000...010 000...001 000...000 0V 1 LSB FS - 1LSB INPUT VOLTAGE (V) 236718 F02 Figure 2. LTC2367-18 Transfer Function ANALOG INPUT The analog inputs of the LTC2367-18 are pseudo-differential in order to reduce any unwanted signal that is common to both inputs. The analog inputs can be modeled by the equivalent circuit shown in Figure 3. The diodes at the input provide ESD protection. In the acquisition phase, each input sees approximately 45pF (CIN) from the sampling CDAC in series with 40 (RON) from the on-resistance of the sampling switch. The IN+ input draws a current spike while charging the CIN capacitor during acquisition. During conversion, the analog inputs draw only a small leakage current. REF RON 40 IN+ REF IN- RON 40 CIN 45pF CIN 45pF BIAS VOLTAGE 236718 F03 Figure 3. The Equivalent Circuit for the Differential Analog Input of the LTC2367-18 236718f 10 LTC2367-18 APPLICATIONS INFORMATION INPUT DRIVE CIRCUITS A low impedance source can directly drive the high impedance input of the LTC2367-18 without gain error. A high impedance source should be buffered to minimize settling time during acquisition and to optimize the distortion performance of the ADC. Minimizing settling time is important even for DC inputs, because the ADC input draws a current spike when entering acquisition. High quality capacitors and resistors should be used in the RC filters since these components can add distortion. NPO and silver mica type dielectric capacitors have excellent linearity. Carbon surface mount resistors can generate distortion from self heating and from damage that may occur during soldering. Metal film surface mount resistors are much less susceptible to both problems. Pseudo-Differential Unipolar Inputs For best performance, a buffer amplifier should be used to drive the analog input of the LTC2367-18. The amplifier provides low output impedance, which produces fast settling of the analog signal during the acquisition phase. It also provides isolation between the signal source and the current spike the ADC input draws. For most applications, we recommend the low power LT6202 ADC driver to drive the LTC2367-18. With a low noise density of 1.9nV/Hz and a low supply current of 3mA, the LT6202 is flexible and may be configured to convert signals of various amplitudes to the 0V to 5V input range of the LTC2367-18. Input Filtering To achieve the full distortion performance of the LTC236718, a low distortion single-ended signal source driven through the LT6202 configured as a unity-gain buffer as shown in Figure 4 can be used to get the full data sheet THD specification of -120dB. The noise and distortion of the buffer amplifier and signal source must be considered since they add to the ADC noise and distortion. Noisy input signals should be filtered prior to the buffer amplifier input with an appropriate filter to minimize noise. The simple 1-pole RC lowpass filter (LPF1) shown in Figure 4 is sufficient for many applications. LPF1 VREF 0V 50 66nF BW = 48kHz LPF2 + LT6202 - 10 IN+ 10nF LTC2367-18 IN- BW = 1.6MHz 236718 F04 Figure 4. Input Signal Chain Another filter network consisting of LPF2 should be used between the buffer and ADC input to both minimize the noise contribution of the buffer and to help minimize disturbances reflected into the buffer from sampling transients. Long RC time constants at the analog inputs will slow down the settling of the analog inputs. Therefore, LPF2 requires a wider bandwidth than LPF1. A buffer amplifier with a low noise density must be selected to minimize degradation of the SNR. The LT6202 can also be used to buffer and convert large true bipolar signals which swing below ground to the 0V to 5V input range of the LTC2367-18. Figure 5a shows the LT6202 being used to convert a 10V true bipolar signal for use by the LTC2367-18. In this case, the LT6202 is configured as an inverting amplifier stage, which acts to attenuate and level shift the input signal to the 0V to 5V input range of the LTC2367-18. In the inverting configuration, the single-ended input signal source no longer directly drives a high impedance input. The input impedance is instead set by resistor RIN. RIN must be chosen carefully based on the source impedance of the signal source. Higher values of RIN tend to degrade both the noise and distortion of the LT6202 and LTC2367-18 as a system. Table 1 shows the resulting SNR and THD for several values of RIN, R1, R2, R3 and R4 in this configuration. Figure 5b shows the resulting FFT when using the LT6202 as shown in Figure 5a. 236718f 11 LTC2367-18 APPLICATIONS INFORMATION VCM = VREF/2 200pF R2 499 R4 402 ADC REFERENCE 3 R3 2k 10F + LT6202 RIN 2k 10V 0V -10V 4 - 5V 1 0V R1 499 200pF 236718 F05a Figure 5a. LT6202 Converting a 10V Bipolar Signal to a 0V to 5V Input Signal 0 SNR = 96.8dB THD = -99dB SINAD = 93.8dB SFDR = 99.6dB -20 AMPLITUDE (dBFS) -40 -60 -80 The REF pin of the LTC2367-18 draws charge (QCONV) from the 47F bypass capacitor during each conversion cycle. The reference replenishes this charge with a DC current, IREF = QCONV/tCYC. The DC current draw of the REF pin, IREF, depends on the sampling rate and output code. If the LTC2367-18 is used to continuously sample a signal at a constant rate, the LTC6655-5 will keep the deviation of the reference voltage over the entire code span to less than 0.5LSBs. -100 -120 -140 -160 -180 0 50 100 150 FREQUENCY (kHz) 200 The LTC2367-18 requires an external reference to define its input range. A low noise, low temperature drift reference is critical to achieving the full datasheet performance of the ADC. Linear Technology offers a portfolio of high performance references designed to meet the needs of many applications. With its small size, low power and high accuracy, the LTC6655-5 is particularly well suited for use with the LTC2367-18. The LTC6655-5 offers 0.025% (max) initial accuracy and 2ppm/C (max) temperature coefficient for high precision applications. The LTC6655-5 is fully specified over the H-grade temperature range and complements the extended temperature operation of the LTC2367-18 up to 125C. We recommend bypassing the LTC6655-5 with a 47F ceramic capacitor (X5R, 0805 size) close to the REF pin. 250 236718 F05b Figure 5b. 32k Point FFT Plot with fIN = 2kHz for Circuit Shown in Figure 5a Table 1. SNR, THD vs RIN for 10V Input Signal RIN () R1 () R2 () R3 () R4 () SNR (dB) THD (dB) 2k 499 499 2k 402 96.8 -99 10k 2.49k 2.49k 10k 2k 96.7 -93.7 100k 24.9k 24.9k 100k 20k 94.2 -93.8 When idling, the REF pin on the LTC2367-18 draws only a small leakage current (< 1A). In applications where a burst of samples is taken after idling for long periods as shown in Figure 6, IREF quickly goes from approximately 0A to a maximum of 0.32mA at 500ksps. This step in DC current draw triggers a transient response in the reference that must be considered since any deviation in the reference output voltage will affect the accuracy of the output CNV 236718 F06 IDLE PERIOD IDLE PERIOD Figure 6. CNV Waveform Showing Burst Sampling 236718f 12 LTC2367-18 APPLICATIONS INFORMATION 0 SNR = 97.2dB THD = -120dB SINAD = 97.1dB SFDR = 122dB -20 code. In applications where the transient response of the reference is important, the fast settling LTC6655-5 reference is also recommended. AMPLITUDE (dBFS) -40 In applications where power management is critical and the external reference may be powered down, it is recommended that REF is kept greater than 2V in order to guarantee a maximum shutdown current of 140A. In such applications, a Schottky diode can be placed between REF and VDD, as shown in Figure 7. -60 -80 -100 -120 -140 -160 -180 0 50 100 150 FREQUENCY (kHz) 200 250 236718 F08 Figure 8. 32k Point FFT with fIN = 2kHz of the LTC2367-18 REF VDD LTC2367-18 236718 F07 Figure 7. A Schottky Diode Between REF and VDD Maintains REF > 2V for Applications Where the Reference May Be Powered Down DYNAMIC PERFORMANCE Fast Fourier Transform (FFT) techniques are used to test the ADC's frequency response, distortion and noise at the rated throughput. By applying a low distortion sine wave and analyzing the digital output using an FFT algorithm, the ADC's spectral content can be examined for frequencies outside the fundamental. The LTC2367-18 provides guaranteed tested limits for both AC distortion and noise measurements. Signal-to-Noise and Distortion Ratio (SINAD) The signal-to-noise and distortion ratio (SINAD) is the ratio between the RMS amplitude of the fundamental input frequency and the RMS amplitude of all other frequency components at the A/D output. The output is band-limited to frequencies from above DC and below half the sampling frequency. Figure 8 shows that the LTC2367-18 achieves a typical SINAD of 97.1dB at a 500kHz sampling rate with a 2kHz input. the RMS amplitude of all other frequency components except the first five harmonics and DC. Figure 8 shows that the LTC2367-18 achieves a typical SNR of 97.2dB at a 500kHz sampling rate with a 2kHz input. Total Harmonic Distortion (THD) Total Harmonic Distortion (THD) is the ratio of the RMS sum of all harmonics of the input signal to the fundamental itself. The out-of-band harmonics alias into the frequency band between DC and half the sampling frequency (fSMPL/2). THD is expressed as: THD= 20log V22 + V32 + V42 +...+ VN2 V1 where V1 is the RMS amplitude of the fundamental fre quency and V2 through VN are the amplitudes of the second through Nth harmonics. POWER CONSIDERATIONS The LTC2367-18 provides two power supply pins: the 2.5V power supply (VDD), and the digital input/output interface power supply (OVDD). The flexible OVDD supply allows the LTC2367-18 to communicate with any digital logic operating between 1.8V and 5V, including 2.5V and 3.3V systems. Signal-to-Noise Ratio (SNR) The signal-to-noise ratio (SNR) is the ratio between the RMS amplitude of the fundamental input frequency and 236718f 13 LTC2367-18 APPLICATIONS INFORMATION Power Supply Sequencing Auto Power-Down The LTC2367-18 does not have any specific power supply sequencing requirements. Care should be taken to adhere to the maximum voltage relationships described in the Absolute Maximum Ratings section. The LTC236718 has a power-on-reset (POR) circuit that will reset the LTC2367-18 at initial power-up or whenever the power supply voltage drops below 1V. Once the supply voltage re-enters the nominal supply voltage range, the POR will reinitialize the ADC. No conversions should be initiated until 20s after a POR event to ensure the reinitialization period has ended. Any conversions initiated before this time will produce invalid results. The LTC2367-18 automatically powers down after a conversion has been completed and powers up once a new conversion is initiated on the rising edge of CNV. During power down, data from the last conversion can be clocked out. To minimize power dissipation during power down, disable SDO and turn off SCK. The auto power-down feature will reduce the power dissipation of the LTC2367-18 as the sampling frequency is reduced. Since power is consumed only during a conversion, the LTC2367-18 remains powered down for a larger fraction of the conversion cycle (tCYC) at lower sample rates, thereby reducing the average power dissipation which scales with the sampling rate as shown in Figure 9. TIMING AND CONTROL The LTC2367-18 conversion is controlled by CNV. A rising edge on CNV will start a conversion and power up the LTC2367-18. Once a conversion has been initiated, it cannot be restarted until the conversion is complete. For optimum performance, CNV should be driven by a clean low jitter signal. Converter status is indicated by the BUSY output which remains high while the conversion is in progress. To ensure that no errors occur in the digitized results, any additional transitions on CNV should occur within 40ns from the start of the conversion or after the conversion has been completed. Once the conversion has completed, the LTC2367-18 powers down and begins acquiring the input signal. Acquisition A proprietary sampling architecture allows the LTC2367-18 to begin acquiring the input signal for the next conversion 527ns after the start of the current conversion. This extends the acquisition time to 1.460s, easing settling requirements and allowing the use of extremely low power ADC drivers. (Refer to the Timing Diagram.) Internal Conversion Clock The LTC2367-18 has an internal clock that is trimmed to achieve a maximum conversion time of 1.5s. DIGITAL INTERFACE The LTC2367-18 has a serial digital interface. The flexible OVDD supply allows the LTC2367-18 to communicate with any digital logic operating between 1.8V and 5V, including 2.5V and 3.3V systems. The serial output data is clocked out on the SDO pin when an external clock is applied to the SCK pin if SDO is enabled. Clocking out the data after the conversion will yield the best performance. With a shift clock frequency of at least 40MHz, a 500ksps throughput is still achieved. The serial output data changes state on the rising edge of SCK and can be captured on the falling edge or next rising edge of SCK. D17 remains valid till the first rising edge of SCK. 3.0 POWER SUPPLY CURRENT (mA) CNV Timing 2.5 2.0 IVDD 1.5 1.0 0.5 0 IOVDD 1 100 200 300 400 SAMPLING RATE (kHz) IREF 500 236718 F09 Figure 9. Power Supply Current of the LTC2367-18 Versus Sampling Rate 236718f 14 LTC2367-18 TIMING DIAGRAMS The serial interface on the LTC2367-18 is simple and straightforward to use. The following sections describe the operation of the LTC2367-18. Several modes are provided depending on whether a single or multiple ADCs share the SPI bus or are daisy chained. serial data output pin SDO. If RDL/SDI is high, SDO is in high impedance. If RDL/SDI is low, SDO is driven. Figure 10 shows a single LTC2367-18 operated in normal mode with CHAIN and RDL/SDI tied to ground. With RDL/SDI grounded, SDO is enabled and the MSB(D17) of the new conversion data is available at the falling edge of BUSY. This is the simplest way to operate the LTC2367-18. Normal Mode, Single Device When CHAIN = 0, the LTC2367-18 operates in normal mode. In normal mode, RDL/SDI enables or disables the CONVERT DIGITAL HOST CNV CHAIN LTC2367-18 RDL/SDI BUSY IRQ SDO DATA IN SCK CLK POWER-DOWN ACQUIRE CONVERT POWER-DOWN CONVERT ACQUIRE CHAIN = 0 RDL/SDI = 0 tCYC tCNVH tCNVL CNV tHOLD tACQ tACQ = tCYC - tHOLD tCONV BUSY tSCK tBUSYLH tSCKH 1 SCK 2 3 tHSDO tDSDOBUSYL SDO tQUIET 16 17 18 tSCKL tDSDO D17 D16 D15 D1 D0 236718 F10 Figure 10. Using a Single LTC2367-18 in Normal Mode 236718f 15 LTC2367-18 TIMING DIAGRAMS Normal Mode, Multiple Devices be used to allow only one LTC2367-18 to drive SDO at a time in order to avoid bus conflicts. As shown in Figure 11, the RDL/SDI inputs idle high and are individually brought low to read data out of each device between conversions. When RDL/SDI is brought low, the MSB of the selected device is output onto SDO. Figure 11 shows multiple LTC2367-18 devices operating in normal mode (CHAIN = 0) sharing CNV, SCK and SDO. By sharing CNV, SCK and SDO, the number of required signals to operate multiple ADCs in parallel is reduced. Since SDO is shared, the RDL/SDI input of each ADC must RDLB RDLA CONVERT CNV CHAIN LTC2367-18 B CNV CHAIN BUSY LTC2367-18 SDO A IRQ DIGITAL HOST SDO RDL/SDI RDL/SDI SCK SCK DATA IN CLK POWER-DOWN CONVERT POWER-DOWN ACQUIRE CONVERT ACQUIRE CHAIN = 0 tCNVL CNV tHOLD BUSY tCONV tBUSYLH RDL/SDIA RDL/SDIB tSCK SCK 1 2 tSCKH 3 16 17 18 tHSDO SDO Hi-Z D17A D16A D15A 19 20 21 34 35 36 tSCKL tDSDO tEN tQUIET tDIS D1A D0A Hi-Z D17B D16B D15B D1B D0B Hi-Z 236718 F11 Figure 11. Normal Mode With Multiple Devices Sharing CNV, SCK and SDO 236718f 16 LTC2367-18 TIMING DIAGRAMS Chain Mode, Multiple Devices number of converters. Figure 12 shows an example with two daisy-chained devices. The MSB of converter A will appear at SDO of converter B after 18 SCK cycles. The MSB of converter A is clocked in at the SDI/RDL pin of converter B on the rising edge of the first SCK. When CHAIN = OVDD, the LTC2367-18 operates in chain mode. In chain mode, SDO is always enabled and RDL/SDI serves as the serial data input pin (SDI) where daisy-chain data output from another ADC can be input. This is useful for applications where hardware constraints may limit the number of lines needed to interface to a large CONVERT OVDD OVDD CNV CHAIN RDL/SDI A CNV CHAIN LTC2367-18 DIGITAL HOST LTC2367-18 RDL/SDI SDO IRQ BUSY B DATA IN SDO SCK SCK CLK POWER-DOWN ACQUIRE CONVERT POWER-DOWN ACQUIRE CONVERT CHAIN = OVDD RDL/SDIA = 0 tCYC tCNVL CNV tHOLD BUSY tCONV tBUSYLH tSCKCH SCK 1 2 3 16 17 tSSDISCK 18 19 20 34 35 36 tSCKL tHSDO tHSDISCK SDOA = RDL/SDIB tQUIET tSCKH tDSDO D17A D16A D15A D1A D0A D17B D16B D15B D1B D0B tDSDOBUSYL SDOB D17A D16A D1A D0A 236718 F12 Figure 12. Chain Mode Timing Diagram 236718f 17 LTC2367-18 BOARD LAYOUT To obtain the best performance from the LTC2367-18 a printed circuit board is recommended. Layout for the printed circuit board (PCB) should ensure the digital and analog signal lines are separated as much as possible. In particular, care should be taken not to run any digital clocks or signals alongside analog signals or underneath the ADC. Recommended Layout The following is an example of a recommended PCB layout. A single solid ground plane is used. Bypass capacitors to the supplies are placed as close as possible to the supply pins. Low impedance common returns for these bypass capacitors are essential to the low noise operation of the ADC. The analog input traces are screened by ground. For more details and information refer to DC1813A, the evaluation kit for the LTC2367-18. Partial Top Silkscreen 236718f 18 LTC2367-18 BOARD LAYOUT Partial Layer 1 Component Side Partial Layer 2 Ground Plane 236718f 19 LTC2367-18 BOARD LAYOUT Partial Layer 3 PWR Plane Partial Layer 4 Bottom Layer 236718f 20 J8 AIN - E7 EXT VREF/2 R14 0 R39 0 JP5 HD1X3-100 EXT_CM AIN+ J4 COUPLING AC DC C46 1F 3 2 1 C8 1F +2.5V R15 OPT HD1X3-100 JP2 CM C18 OPT C17 10F JP1 HD1X3-100 C47 OPT C48 10F 6.3V 4 2 5 4 +3.3V C2 0.1F R3 CLK 33 TO CPLD R41 OPT R40 OPT R9 OPT C49 OPT C63 10F 6.3V 2 C44 1F V+ 4 C59 1F -IN1 OUT1 1 C57 0.1F V- C43 0.1F C55 1F 3 +IN1 V- C61 10F 6.3V C42 15pF R32 0 U15 5 LT6202CS5 V+ V+ U2 R6 3 U8 3 NC7SZ04P5X NC7SVU04P5X 1k 5 +3.3V C1 0.1F COUPLING AC DC 1 R5 49.9 1206 2 R2 1k +3.3V 2 J1 CLKIN 1 3 C5 0.1F 2 C60 0.1F C58 OPT R35 OPT R45 O R32 10 R31 OPT C11 0.1F 9V TO 10V +2.5V C9 10F 6.3V +3.3V C10 0.1F C6 10F 6.3V C7 0.1F R46 O C20 47F 6.3V 0805 3 2 1 JP6 FS C56 0.1F 3 SDO 1 3 5 7 9 11 13 9V TO 10V J3 DC590 2 4 6 8 10 12 14 R17 R13 2k 1k 4 VSS U7 C14 0.1F 8 24LC025-I/ST VCC SCL SCK SDA WP CNV ARRAY A2 EEPROM A1 A0 3 6 5 7 3 2 1 R10 4.99k R11 4.99k CLKOUT C16 1 0.1F DB0 DB1 DB2 DB3 DB4 DB5 DB6 DB7 DB8 DB9 DB10 DB11 DB12 DB13 DB14 DB15 DB16 DB17 3 5 2 CNVST_33 FROM CPLD U4 NC7SVU04P5X +3.3V C4 0.1F R12 4.99k 39 37 35 33 31 29 27 25 23 21 19 17 15 13 11 9 7 5 3 1 236718 BL 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 J2 CON-EDGE 40-100 R4 7 33 4 8 +3.3V C3 0.1F R8 33 DC590 DETECT TO CPLD 5 PR\ Q CLR\ Q\ 2 D VCC 1 CP GND +3.3V C13 0.8VREF 0.1F VREF 6 4 U3 NL17SZ74 +3.3V HD1X3-100 U6 OPT NC7SZ66P5X 5 C39 CNV VCC 0.01F R16 9 2 B A 1 0 4 NPO CNV 13 SCK IN+ SCK OE 4 C65 14 SDO SDO OPT R19 LTC2367-18 GND 11 BUSY BUSY 0805 NPO 0 3 IN- 12 RD RDL/SDI C40 5 R58 OPT O R7 +3.3V NPO R38 1k OPT U9 C15 NC7SZ04P5X 5 0.1F 2 4 1 2 3 4 U20 LTC6655AHMS8-5 8 SHDN GND 7 VIN OUT_F 6 GND OUT_S 5 GND GND GND GND GND GND 3 6 10 16 1 - + 3 VDD 2 15 OV DD REF 7 8 REF R1 33 LTC2367-18 BOARD LAYOUT Partial Schematic of Demoboard 236718f 21 LTC2367-18 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DE Package 16-Lead Plastic DFN (4mm x 3mm) (Reference LTC DWG # 05-08-1732 Rev O) 0.70 0.05 3.30 0.05 3.60 0.05 2.20 0.05 1.70 0.05 PACKAGE OUTLINE 0.25 0.05 0.45 BSC 3.15 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 4.00 0.10 (2 SIDES) R = 0.05 TYP 9 R = 0.115 TYP 0.40 0.10 16 3.30 0.10 3.00 0.10 (2 SIDES) 1.70 0.10 PIN 1 NOTCH R = 0.20 OR 0.35 x 45 CHAMFER PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF 0.75 0.05 (DE16) DFN 0806 REV O 8 1 0.23 0.05 0.45 BSC 3.15 REF 0.00 - 0.05 BOTTOM VIEW--EXPOSED PAD NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WGED-3) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 236718f 22 LTC2367-18 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MS Package 16-Lead Plastic MSOP (Reference LTC DWG # 05-08-1669 Rev O) 0.889 0.127 (.035 .005) 5.23 (.206) MIN 3.20 - 3.45 (.126 - .136) 4.039 0.102 (.159 .004) (NOTE 3) 0.50 (.0197) BSC 0.305 0.038 (.0120 .0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) DETAIL "A" 3.00 0.102 (.118 .004) (NOTE 4) 4.90 0.152 (.193 .006) 0 - 6 TYP 0.280 0.076 (.011 .003) REF 16151413121110 9 GAUGE PLANE 0.53 0.152 (.021 .006) DETAIL "A" 0.18 (.007) SEATING PLANE 1.10 (.043) MAX 0.17 -0.27 (.007 - .011) TYP 1234567 8 0.50 (.0197) BSC NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 0.86 (.034) REF 0.1016 0.0508 (.004 .002) MSOP (MS16) 1107 REV O 236718f 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 23 LTC2367-18 TYPICAL APPLICATION LT6202 Converting a 10V Bipolar Signal to a 0V to 5V Input Signal Into the LTC2367-18 LTC6655-5 VIN VOUT_F VOUT_S 8V 5V 200pF R2 3k 10F 47F 5 V+ R4 402 3 R3 2k LT6202 + 1 4 2.5V 5V 0V 10 - IN+ 10nF REF VDD LTC2367-18 IN- V- 2 10V 0V -10V RIN 2k R1 499 236718 TA02 -3V 220pF RELATED PARTS PART NUMBER ADCs LTC2379-18/LTC2378-18 LTC2377-18/LTC2376-18 DESCRIPTION COMMENTS 18-Bit, 1.6Msps/1Msps/500ksps/250ksps Serial, Low 2.5V Supply, Differential Input, 101.2dB SNR, 5V Input Range, Power ADC DGC, Pin-Compatible Family in MSOP-16 and 4mm x 3mm DFN-16 Packages LTC2380-16/LTC2378-16 16-Bit, 2Msps/1Msps/500ksps/250ksps Serial, Low 2.5V Supply, Differential Input, 96.2dB SNR, 5V Input Range, DGC, LTC2377-16/LTC2376-16 Power ADC Pin-Compatible Family in MSOP-16 and 4mm x 3mm DFN-16 Packages LTC2383-16/LTC2382-16/ 16-Bit, 1Msps/500ksps/250ksps Serial, Low 2.5V Supply, Differential Input, 92dB SNR, 2.5V Input Range, PinLTC2381-16 Power ADC Compatible Family in MSOP-16 and 4mm x 3mm DFN-16 Packages LTC2393-16/LTC2392-16/ 16-Bit, 1Msps/500ksps/250ksps Parallel/Serial ADC 5V Supply, Differential Input, 94dB SNR, 4.096V Input Range, PinLTC2391-16 Compatible Family in 7mm x 7mm LQFP-48 and QFN-48 Packages LTC2362 12-Bit, 500ksps Serial ADC 2.35V to 3.6V 3.3mW, 6- and 8-Lead TSOT-23 Packages LTC2302/LTC2306 12-Bit, 500ksps, 1-/2-Channel, Low Noise, ADC 5V Supply, 14mW at 500ksps, DFN-10 Package DACS LTC2757 18-Bit, Single Parallel IOUT SoftSpanTM DAC 1LSB INL/DNL, Software-Selectable Ranges, 7mm x 7mm LQFP-48 Package 1LSB INL/DNL, MSOP-8 Package, 0V to 5V Output LTC2641 16-Bit/14-Bit/12-Bit Single Serial VOUT DACs SC70 6-Pin Package, Internal Reference, 1LSB INL (12 Bits) LTC2630 12-Bit/10-Bit/8-Bit Single VOUT DACs References LTC6655 Precision Low Drift Low Noise Buffered Reference 5V/2.5V, 5ppm/C, 0.25ppm Peak-to-Peak Noise, MSOP-8 Package LTC6652 Precision Low Drift Low Noise Buffered Reference 5V/2.5V, 5ppm/C, 2.1ppm Peak-to-Peak Noise, MSOP-8 Package Amplifiers LT6202/LT6203 Single/Dual 100MHz Rail-to-Rail Input/Output Noise 1.9nVHz, 3mA Maximum, 100MHz Gain Bandwidth Low Power Amplifiers LT6200/LT6200-5/ 165MHz/800MHz/1.6GHz Op Amp with Low Noise Voltage: 0.95nV/Hz (100kHz), Low Distortion: -80dB at LT6200-10 Unity Gain/AV = 5/AV = 10 1MHz, TSOT23-6 Package 236718f 24 Linear Technology Corporation LT 0112 * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 2012