16-Bit, 80/100 MSPS ADC AD9446

Transcription

1 6-Bit, 8/ MSPS ADC FEATURES MSPS guaranteed sampling rate (-) 8.6 dbfs SNR with MHz input (.8 V p-p input, 8 MSPS) 8.6 dbfs SNR with MHz input (. V p-p input, 8 MSPS) 89 dbc SFDR with MHz input (. V p-p input, 8 MSPS) 95 dbfs -tone SFDR with 9.8 MHz and.8 MHz ( MSPS) 6 fsec rms jitter Excellent linearity DNL = ±.4 LSB typical INL = ±. LSB typical. V p-p to 4. V p-p differential full-scale input Buffered analog inputs LVDS outputs (ANSI-644 compatible) or CMOS outputs Data format select (offset binary or twos complement) Output clock available. V and 5 V supply operation APPLICATIONS MRI receivers Multicarrier, multimode cellular receivers Antenna array positioning Power amplifier linearization Broadband wireless Radar Infrared imaging Communications instrumentation GENERAL DESCRIPTION The is a 6-bit, monolithic, sampling analog-to-digital converter (ADC) with an on-chip track-and-hold circuit. It is optimized for performance, small size, and ease of use. The product operates up to a MSPS, providing superior SNR for instrumentation, medical imaging, and radar receivers employing baseband (< MHz) IF frequencies. The ADC requires. V and 5. V power supplies and a low voltage differential input clock for full performance operation. No external reference or driver components are required for many applications. Data outputs are CMOS or LVDS compatible (ANSI-644 compatible) and include the means to reduce the overall current needed for short trace distances. VIN+ VIN CLK+ CLK BUFFER FUNCTIONAL BLOCK DIAGRAM AVDD AVDD T/H CLOCK AND TIMING MANAGEMENT PIPELINE ADC REF 6 CMOS OR LVDS OUTPUT STAGING VREF SENSE REFT REFB Figure. DFS DCS MODE OUTPUT MODE OR D5 TO D DCO Optional features allow users to implement various selectable operating conditions, including input range, data format select, and output data mode. The is available in a Pb-free, -lead, surface-mount, plastic package (-lead TQFP/EP) specified over the industrial temperature range 4 C to +85 C. PRODUCT HIGHLIGHTS. True 6-bit linearity.. High performance: outstanding SNR performance for baseband IFs in data acquisition, instrumentation, magnetic resonance imaging, and radar receivers.. Ease of use: on-chip reference and high input impedance track-and-hold with adjustable analog input range and an output clock simplifies data capture. 4. Packaged in a Pb-free, -lead TQFP/EP package. 5. Clock duty cycle stabilizer (DCS) maintains overall ADC performance over a wide range of clock pulse widths. 6. OR (out-of-range) outputs indicate when the signal is beyond the selected input range Rev. Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 96, Norwood, MA 6-96, U.S.A. Tel: Fax: Analog Devices, Inc. All rights reserved.

2 TABLE OF CONTENTS Features... Applications... General Description... Functional Block Diagram... Product Highlights... Revision History... Specifications... DC Specifications... AC Specifications... 4 Digital Specifications... 6 Switching Specifications... 6 Timing Diagrams... 7 Absolute Maximum Ratings... 8 Thermal Resistance... 8 Terminology...9 Pin Configurations and Function Descriptions... Equivalent Circuits... 5 Typical Performance Characteristics... 6 Theory of Operation... 4 Analog Input and Reference Overview... 4 Clock Input Considerations... 6 Power Considerations... 7 Digital Outputs... 7 Timing... 7 Operational Mode Selection... 8 Evaluation Board... 9 Outline Dimensions... 6 Ordering Guide... 6 ESD Caution... 8 REVISION HISTORY /5 Revision : Initial Version Rev. Page of 6

3 SPECIFICATIONS DC SPECIFICATIONS AVDD =. V, AVDD = 5. V, =. V, LVDS mode, specified minimum sampling rate,. V p-p differential input, internal trimmed reference (.6 V mode), AIN =. dbfs, DCS on, unless otherwise noted. Table. BSVZ-8 BSVZ- Parameter Temp Min Typ Max Min Typ Max Unit RESOLUTION Full 6 6 Bits ACCURACY No Missing Codes Full Guaranteed Guaranteed Offset Error Full 5 ± ±. +5 mv Gain Error Full ±.6 + ±.5 + % FSR 5 C ±. + ±. + % FSR Differential Nonlinearity (DNL) Full.75 ± ± LSB Integral Nonlinearity (INL) 5 C 5 ± ±. +6 LSB VOLTAGE REFERENCE Output Voltage VREF =.6 V (. V p-p Analog Input Range) Full.6.6 V Load ma Full ± ± mv Reference Input Current (External.6 V Reference) Full μa INPUT REFERRED NOISE 5 C.5.9 LSB rms ANALOG INPUT Input Span VREF =.6 V Full.. V p-p VREF =. V (External) Full.. V p-p Internal Input Common-Mode Voltage Full.5.5 V External Input Common-Mode Voltage Full V Input Resistance Full kω Input Capacitance Full 6 6 pf POWER SUPPLIES Supply Voltage AVDD Full V AVDD Full V LVDS Outputs Full V CMOS Outputs Full V Supply Current IAVDD Full ma IAVDD Full ma I LVDS Outputs Full ma I CMOS Outputs Full 4 4 ma PSRR Offset Full mv/v Gain Full.. %/V POWER CONSUMPTION LVDS Outputs Full W CMOS Outputs (DC Input) Full.. W Measured at the maximum clock rate, fin = 5 MHz, full-scale sine wave, with a Ω differential termination on each pair of output bits for LVDS output mode and approximately 5 pf loading on each output bit for CMOS output mode. Input capacitance or resistance refers to the effective impedance between one differential input pin and. Refer to Figure 6 for the equivalent analog input structure. Rev. Page of 6

4 AC SPECIFICATIONS AVDD =. V, AVDD = 5. V, =. V, LVDS mode, specified minimum sample rate,. V p-p differential input, internal trimmed reference (.6 V mode), AIN = dbfs, DCS on, unless otherwise noted. Table. BSVZ-8 BSVZ- Parameter Temp Min Typ Max Min Typ Max Unit SIGNAL-TO-NOISE RATIO (SNR) fin = MHz 5 C db fin = MHz 5 C db Full db fin = 7 MHz 5 C db Full db fin = 9 MHz 5 C db fin = 5 MHz 5 C db fin = 7 MHz 5 C db fin = MHz ( V p-p Input) 5 C db fin = MHz ( V p-p Input) 5 C db fin = 7 MHz ( V p-p Input) 5 C db fin = 9 MHz ( V p-p Input) 5 C db fin = 5 MHz ( V p-p Input) 5 C db fin = 7 MHz ( V p-p Input) 5 C db SIGNAL-TO-NOISE AND DISTORTION (SINAD) fin = MHz 5 C db fin = MHz 5 C db Full db fin = 7 MHz 5 C db Full db fin = 9 MHz 5 C db fin = 5 MHz 5 C db fin = 7 MHz 5 C db fin = MHz ( V p-p Input) 5 C db fin = MHz ( V p-p Input) 5 C db fin = 7 MHz ( V p-p Input) 5 C db fin = 9 MHz ( V p-p Input) 5 C db fin = 5 MHz ( V p-p Input) 5 C db fin = 7 MHz ( V p-p Input) 5 C db EFFECTIVE NUMBER OF BITS (ENOB) fin = MHz 5 C.. Bits fin = MHz 5 C..9 Bits fin = 7 MHz 5 C.9.8 Bits fin = 9 MHz 5 C..7 Bits fin = 5 MHz 5 C..6 Bits fin = 7 MHz 5 C.8.6 Bits Rev. Page 4 of 6

5 BSVZ-8 BSVZ- Parameter Temp Min Typ Max Min Typ Max Unit SPURIOUS-FREE DYNAMIC RANGE (SFDR, Second or Third Harmonic) fin = MHz 5 C dbc fin = MHz 5 C dbc Full 8 79 dbc fin = 7 MHz 5 C dbc Full dbc fin = 9 MHz 5 C dbc fin = 5 MHz 5 C 8 8 dbc fin = 7 MHz 5 C dbc fin = MHz ( V p-p Input) 5 C 9 94 dbc fin = MHz ( V p-p Input) 5 C 9 9 dbc fin = 7 MHz ( V p-p Input) 5 C 9 9 dbc fin = 9 MHz ( V p-p Input) 5 C 9 89 dbc fin = 5 MHz ( V p-p Input) 5 C dbc fin = 7 MHz ( V p-p Input) 5 C 77 8 dbc WORST SPUR EXCLUDING SECOND OR THIRD HARMONICS fin = MHz 5 C dbc fin = MHz 5 C dbc Full dbc fin = 7 MHz 5 C dbc Full dbc fin = 9 MHz 5 C dbc fin = 5 MHz 5 C dbc fin = 7 MHz 5 C 95 9 dbc fin = MHz ( V p-p Input) 5 C 97 9 dbc fin = MHz ( V p-p Input) 5 C dbc fin = 7 MHz ( V p-p Input) 5 C dbc fin = 9 MHz ( V p-p Input) 5 C dbc fin = 5 MHz ( V p-p Input) 5 C dbc fin = 7 MHz ( V p-p Input) 5 C 9 95 dbc TWO-TONE SFDR fin =.8 7 dbfs, 5 C dbfs dbfs fin = 7. 7 dbfs, 5 C 9 9 dbfs dbfs ANALOG BANDWIDTH Full 5 54 MHz Rev. Page 5 of 6

6 DIGITAL SPECIFICATIONS AVDD =. V, AVDD = 5. V, =. V, RLVDS_BIAS =.74 kω, unless otherwise noted. Table. BSVZ-8 BSVZ- Parameter Temp Min Typ Max Min Typ Max Unit CMOS LOGIC INPUTS (DFS, DCS MODE, OUTPUT MODE) High Level Input Voltage Full.. V Low Level Input Voltage Full.8.8 V High Level Input Current Full μa Low Level Input Current Full + + μa Input Capacitance Full pf DIGITAL OUTPUT BITS CMOS MODE (D to D5, OTR) =. V High Level Output Voltage Full.5.5 V Low Level Output Voltage Full.. V DIGITAL OUTPUT BITS LVDS MODE (D to D5, OTR) VOD Differential Output Voltage Full mv VOS Output Offset Voltage Full V CLOCK INPUTS (CLK+, CLK ) Differential Input Voltage Full.. V Common-Mode Voltage Full V Input Resistance Full kω Input Capacitance Full pf Output voltage levels measured with 5 pf load on each output. LVDS RTERM = Ω. SWITCHING SPECIFICATIONS AVDD =. V, AVDD = 5. V, =. V, unless otherwise noted. Table 4. BSVZ-8 BSVZ- Parameter Temp Min Typ Max Min Typ Max Unit CLOCK INPUT PARAMETERS Maximum Conversion Rate Full 8 MSPS Minimum Conversion Rate Full MSPS CLK Period Full.5 ns CLK Pulse Width High (tclkh) Full ns CLK Pulse Width Low (tclkl) Full ns DATA OUTPUT PARAMETERS Output Propagation Delay CMOS (tpd) (Dx, DCO+) Full.5.5 ns Output Propagation Delay LVDS (tpd) (Dx+), (tcpd) (DCO+) Full ns Pipeline Delay (Latency) Full Cycles Aperture Delay (ta) Full ns Aperture Uncertainty (Jitter, tj) Full 6 6 fsec rms With duty cycle stabilizer (DCS) enabled. Output propagation delay is measured from clock 5% transition to data 5% transition with 5 pf load. LVDS RTERM = Ω. Measured from the 5% point of the rising edge of CLK+ to the 5% point of the data transition. Rev. Page 6 of 6

7 t CLKH t CLKL /f S TIMING DIAGRAMS N N A IN N + CLK+ CLK t PD DATA OUT DCO+ N N N N + CLOCK CYCLES DCO 549- t CPD Figure. LVDS Mode Timing Diagram N N VIN t CLKL N + N + t CLKH CLK CLK+ t PD CLOCK CYCLES DX N N N N DCO+ DCO 549- Figure. CMOS Timing Diagram Rev. Page 7 of 6

8 ABSOLUTE MAXIMUM RATINGS Table 5. Parameter With Respect to Rating ELECTRICAL AVDD. V to +4 V AVDD. V to +6 V D. V to +4 V D. V to +. V AVDD 4 V to +4 V AVDD 4 V to +6 V AVDD AVDD 4 V to +6 V D± to D5± D. V to +. V CLK+/CLK. V to AVDD +. V OUTPUT MODE,. V to AVDD +. V DCS MODE, DFS VIN+, VIN. V to AVDD +. V VREF. V to AVDD +. V SENSE. V to AVDD +. V REFT, REFB. V to AVDD +. V ENVIRONMENTAL Storage Temperature 65 C to +5 C Range Operating Temperature 4 C to +85 C Range Lead Temperature C (Soldering sec) Junction Temperature 5 C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. THERMAL RESISTANCE The heat sink of the package must be soldered to ground. Table 6. Package Type θja θjb θjc Unit -lead TQFP/EP C/W Typical θja = 9.8 C/W (heat sink soldered) for multilayer board in still air. Typical θjb = 8. C/W (heat sink soldered) for multilayer board in still air. Typical θjc = C/W (junction to exposed heat sink) represents the thermal resistance through heat sink path. Airflow increases heat dissipation, effectively reducing θja. Also, more metal directly in contact with the package leads from metal traces through holes, ground, and power planes reduces the θja. It is required that the exposed heat sink be soldered to the ground plane. ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Rev. Page 8 of 6

9 TERMINOLOGY Analog Bandwidth (Full Power Bandwidth) The analog input frequency at which the spectral power of the fundamental frequency (as determined by the FFT analysis) is reduced by db. Aperture Delay (ta) The delay between the 5% point of the rising edge of the clock and the instant at which the analog input is sampled. Aperture Uncertainty (Jitter, tj) The sample-to-sample variation in aperture delay. Clock Pulse Width and Duty Cycle Pulse width high is the minimum amount of time that the clock pulse should be left in the Logic state to achieve rated performance. Pulse width low is the minimum time the clock pulse should be left in the low state. At a given clock rate, these specifications define an acceptable clock duty cycle. Differential Nonlinearity (DNL, No Missing Codes) An ideal ADC exhibits code transitions that are exactly LSB apart. DNL is the deviation from this ideal value. Guaranteed no missing codes to 6-bit resolution indicates that all 65,56 codes must be present over all operating ranges. Effective Number of Bits (ENOB) The effective number of bits for a sine wave input at a given input frequency can be calculated directly from its measured SINAD using the following formula: ( SINAD.76) ENOB = 6. Gain Error The first code transition should occur at an analog value of ½ LSB above negative full scale. The last transition should occur at an analog value of ½ LSB below the positive full scale. Gain error is the deviation of the actual difference between first and last code transitions and the ideal difference between first and last code transitions. Integral Nonlinearity (INL) The deviation of each individual code from a line drawn from negative full scale through positive full scale. The point used as negative full scale occurs ½ LSB before the first code transition. Positive full scale is defined as a level ½ LSB beyond the last code transition. The deviation is measured from the middle of each particular code to the true straight line. Maximum Conversion Rate The clock rate at which parametric testing is performed. Minimum Conversion Rate The clock rate at which the SNR of the lowest analog signal frequency drops by no more than db below the guaranteed limit. Offset Error The major carry transition should occur for an analog value of ½ LSB below VIN+ = VIN. Offset error is defined as the deviation of the actual transition from that point. Out-of-Range Recovery Time The time it takes for the ADC to reacquire the analog input after a transition from % above positive full scale to % above negative full scale, or from % below negative full scale to % below positive full scale. Output Propagation Delay (tpd) The delay between the clock rising edge and the time when all bits are within valid logic levels. Power-Supply Rejection Ratio The change in full scale from the value with the supply at the minimum limit to the value with the supply at the maximum limit. Signal-to-Noise and Distortion (SINAD) The ratio of the rms input signal amplitude to the rms value of the sum of all other spectral components below the Nyquist frequency, including harmonics but excluding dc. Signal-to-Noise Ratio (SNR) The ratio of the rms input signal amplitude to the rms value of the sum of all other spectral components below the Nyquist frequency, excluding the first six harmonics and dc. Spurious-Free Dynamic Range (SFDR) The ratio of the rms signal amplitude to the rms value of the peak spurious spectral component. The peak spurious component may be a harmonic. SFDR can be reported in dbc (that is, degrades as signal level is lowered) or dbfs (always related back to converter full scale). Temperature Drift The temperature drift for offset error and gain error specifies the maximum change from the initial (5 C) value to the value at TMIN or TMAX. Total Harmonic Distortion (THD) The ratio of the rms input signal amplitude to the rms value of the sum of the first six harmonic components. Two-Tone SFDR The ratio of the rms value of either input tone to the rms value of the peak spurious component. The peak spurious component may or may not be an IMD product. Rev. Page 9 of 6

10 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS AVDD AVDD AVDD AVDD AVDD AVDD OR+ OR D5+ (MSB) D5 D4+ D4 D+ D D+ D D+ D DCS MODE DNC OUTPUT MODE PIN D+ 7 D DFS 4 7 D9+ LVDS_BIAS 5 7 D9 AVDD 6 7 D8+ SENSE 7 69 D8 VREF REFT REFB AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD VIN+ VIN AVDD LVDS MODE TOP VIEW (Not to Scale) 68 DCO+ 67 DCO 66 D7+ 65 D D6+ 6 D6 6 D5+ 59 D5 58 D4+ 57 D4 56 D+ 55 D 54 D+ 5 D 5 D+ 5 D DNC = DO NOT CONNECT AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD CLK+ CLK AVDD AVDD AVDD D (LSB) D+ Figure 4. -Lead TQFP/EP Pin Configuration in LVDS Mode Rev. Page of 6

11 Table 7. Pin Function Descriptions -Lead TQFP/EP in LVDS Mode Pin No. Mnemonic Description DCS MODE Clock Duty Cycle Stabilizer (DCS) Control Pin. CMOS compatible. DCS = low () to enable DCS (recommended); DCS = high (AVDD) to disable DCS. DNC Do Not Connect. These pins should float. OUTPUT MODE CMOS-Compatible Output Logic Mode Control Pin. OUTPUT MODE = for CMOS mode; OUTPUT MODE = (AVDD) for LVDS outputs. 4 DFS Data Format Select Pin. CMOS control pin that determines the format of the output data. DFS = high (AVDD) for twos complement; DFS = low (ground) for offset binary format. 5 LVDS_BIAS Set Pin for LVDS Output Current. Place.7 kω resistor terminated to. 6, 8 to, to 4, 6, 8, AVDD. V (±5%) Analog Supply. 4 to 45, 9 to 97 7 SENSE Reference Mode Selection. Connect to for internal.6 V reference (. V p-p analog input range); connect to AVDD for external reference. 8 VREF.6 V Reference I/O. Function dependent on SENSE and external programming resistors. Decouple to ground with. μf and μf capacitors. 9,, 4, 9, 4, 46, 9, 98, 99,, Exposed Heat Sink Analog Ground. The exposed heat sink on the bottom of the package must be connected to. REFT Differential Reference Output. Decoupled to ground with. μf capacitor and to REFB (Pin ) with. μf and μf capacitors. REFB Differential Reference Output. Decoupled to ground with a. μf capacitor and to REFT (Pin ) with. μf and μf capacitors. to 7, 5 to, 5, 7 AVDD 5. V Analog Supply (±5%). VIN+ Analog Input True. VIN Analog Input Complement. 4 CLK+ Clock Input True. 4 CLK Clock Input Complement. 47, 6, 75, 87, Digital Output Ground. 48, 64, 76, 88. V Digital Output Supply (. V to.6 V). 49 D (LSB) D Complement Output Bit (LVDS Levels). 5 D+ D True Output Bit. 5 D D Complement Output Bit. 5 D+ D True Output Bit. 5 D D Complement Output Bit. 54 D+ D True Output Bit. 55 D D Complement Output Bit. 56 D+ D True Output Bit. 57 D4 D4 Complement Output Bit. 58 D4+ D4 True Output Bit. 59 D5 D5 Complement Output Bit. 6 D5+ D5 True Output Bit. 6 D6 D6 Complement Output Bit. 6 D6+ D6 True Output Bit. 65 D7 D7 Complement Output Bit. 66 D7+ D7 True Output Bit. 67 DCO Data Clock Output Complement. 68 DCO+ Data Clock Output True. 69 D8 D8 Complement Output Bit. 7 D8+ D8 True Output Bit. 7 D9 D9 Complement Output Bit. 7 D9+ D9 True Output Bit. 7 D D Complement Output Bit. 74 D+ D True Output Bit. 77 D D Complement Output Bit. 78 D+ D True Output Bit. Rev. Page of 6

12 Pin No. Mnemonic Description 79 D D Complement Output Bit. 8 D+ D True Output Bit. 8 D D Complement Output Bit 8 D+ D True Output Bit. 8 D4 D4 Complement Output Bit 84 D4+ D4 True Output Bit. 85 D5 D5 Complement Output Bit. 86 D5+ (MSB) D5 True Output Bit. 89 OR Out-of-Range Complement Output Bit. 9 OR+ Out-of-Range True Output Bit. Rev. Page of 6

13 AVDD AVDD AVDD AVDD AVDD AVDD OR+ D5+ (MSB) D4+ D+ D+ D+ D+ D9+ D8+ D7+ D6+ D DCS MODE DNC OUTPUT MODE PIN D4+ 7 D+ DFS 4 7 D+ LVDS_BIAS 5 7 D+ AVDD 6 7 D+ (LSB) SENSE 7 69 DNC VREF REFT REFB AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD VIN+ VIN AVDD CMOS MODE TOP VIEW (Not to Scale) 68 DCO+ 67 DCO 66 DNC 65 DNC DNC 6 DNC 6 DNC 59 DNC 58 DNC 57 DNC 56 DNC 55 DNC 54 DNC 5 DNC 5 DNC 5 DNC DNC = DO NOT CONNECT AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD CLK+ CLK AVDD AVDD AVDD DNC DNC Figure 5. -Lead TQFP/EP Pin Configuration in CMOS Mode Rev. Page of 6

14 Table 8. Pin Function Descriptions -Lead TQFP/EP in CMOS Mode Pin No. Mnemonic Description DCS MODE Clock Duty Cycle Stabilizer (DCS) Control Pin. CMOS compatible. DCS = low () to enable DCS (recommended); DCS = high (AVDD) to disable DCS., 49 to 6, 65 to 66, 69, DNC Do Not Connect. These pins should float. OUTPUT MODE CMOS-Compatible Output Logic Mode Control Pin. OUTPUT MODE = for CMOS mode; OUTPUT MODE = (AVDD) for LVDS outputs. 4 DFS Data Format Select Pin. CMOS control pin that determines the format of the output data. DFS = high (AVDD) for twos complement; DFS = low (ground) for offset binary format. 5 LVDS_BIAS Set Pin for LVDS Output Current. Place.7 kω resistor terminated to. 6, 8 to, to 4, 6, AVDD. V (±5%) Analog Supply. 8, 4 to 45, 9 to 97 7 SENSE Reference Mode Selection. Connect to for internal V reference; connect to AVDD for external reference. 8 VREF.6 V Reference I/O. Function dependent on SENSE and external programming resistors. Decouple to ground with. μf and μf capacitors. 9,, 4, 9, 4, 46, 9, 98, 99,, Exposed Heat Sink Analog Ground. The exposed heat sink on the bottom of the package must be connected to. REFT Differential Reference Output. Decoupled to ground with. μf capacitor and to REFB (Pin ) with. μf and μf capacitors. REFB Differential Reference Output. Decoupled to ground with a. μf capacitor and to REFT (Pin ) with. μf and μf capacitors. to 7, 5 to, 5, 7 AVDD 5. V Analog Supply (±5%). VIN+ Analog Input True. VIN Analog Input Complement. 4 CLK+ Clock Input True. 4 CLK Clock Input Complement. 47, 6, 75, 87, Digital Output Ground. 48, 64, 76, 88. V Digital Output Supply (. V to.6 V). 67 DCO Data Clock Output Complement. 68 DCO+ Data Clock Output True. 7 D+ (LSB) D True Output Bit (CMOS levels). 7 D+ D True Output Bit. 7 D+ D True Output Bit. 7 D+ D True Output Bit. 74 D4+ D4 True Output Bit. 77 D5+ D5 True Output Bit. 78 D6+ D6 True Output Bit. 79 D7+ D7 True Output Bit. 8 D8+ D8 True Output Bit. 8 D9+ D9 True Output Bit. 8 D+ D True Output Bit. 8 D+ D True Output Bit. 84 D+ D True Output Bit. 85 D+ D True Output Bit. 86 D4+ D4 True Output Bit. 89 D5+ (MSB) D5 True Output Bit. 9 OR+ Out-of-Range True Output Bit. Rev. Page 4 of 6

15 EQUIVALENT CIRCUITS AVDD VIN+ 6pF kω.5v X T/H AVDD kω DX VIN 6pF Figure 6. Equivalent Analog Input Circuit Figure 9. Equivalent CMOS Digital Output Circuit VDD K.V LVDSBIAS.74kΩ I LVDSOUT Figure 7. Equivalent LVDS_BIAS Circuit DCS MODE, OUTPUT MODE, DFS kω Figure. Equivalent Digital Input Circuit, DFS, DCS MODE, OUTPUT MODE 549- AVDD kω kω V V CLK+ CLK DX DX+.5kΩ.5kΩ V V Figure 8. Equivalent LVDS Digital Output Circuit Figure. Equivalent Sample Clock Input Circuit 549- Rev. Page 5 of 6

16 TYPICAL PERFORMANCE CHARACTERISTICS AVDD =. V, AVDD = 5. V, =. V, rated sample rate, LVDS mode, DCS enabled, TA = 5 C,. V p-p differential input, AIN = dbfs, internal trimmed reference (nominal VREF =.6 V), unless otherwise noted. AMPLITUDE (dbfs) SNR = 79.7dB ENOB =.BITS SFDR = 9dBc FREQUENCY (MHz) Figure. - 64k Point Single-Tone FFT/ MSPS/. MHz 549- MSPS SNR = 78.9dB ENOB =.7BITS SFDR = 84dBc FREQUENCY (MHz) Figure k Point Single-Tone FFT/ MSPS/9.6 MHz AMPLITUDE (dbfs) SNR = 79.5dB ENOB =.9BITS SFDR = 9dBc FREQUENCY (MHz) Figure. - 64k Point Single-Tone FFT/ MSPS/. MHz AMPLITUDE (dbfs) 549- DNL ERROR (MSB) OUTPUT CODE Figure 6. - DNL Error vs. Output Code, MSPS,. MHz MSPS SNR = 79.dB ENOB =.9BITS SFDR = 86dBc FREQUENCY (MHz) Figure k Point Single-Tone FFT/ MSPS/7. MHz AMPLITUDE (dbfs) INL ERROR (MSB) OUTPUT CODE Figure 7. - INL Error vs. Output Code, MSPS,. MHz Rev. Page 6 of 6

17 AMPLITUDE (dbfs) SNR = 8.8dB ENOB =.BITS SFDR = 9dBc FREQUENCY (MHz) Figure k Point Single-Tone FFT/8 MSPS/. MHz AMPLITUDE (dbfs) SNR = 79.5dB ENOB =.7BITS SFDR = 9dBc FREQUENCY (MHz) Figure k Point Single-Tone FFT/8 MSPS/. MHz SNR = 8.6dB ENOB =.BITS SFDR = 89dBc FREQUENCY (MHz) Figure k Point Single-Tone FFT/8 MSPS/. MHz AMPLITUDE (dbfs) DNL ERROR (MSB) OUTPUT CODE Figure. -8 DNL Error vs. Output Code, 8 MSPS,. MHz 549- AMPLITUDE (dbfs) MSPS SNR = 8.6dB ENOB =.9BITS SFDR = 85dBc FREQUENCY (MHz) Figure k Point Single-Tone FFT/8 MSPS/7. MHz 549- INL ERROR (MSB) OUTPUT CODE Figure. -8 INL Error vs. Output Code, 8 MSPS,. MHz 549- Rev. Page 7 of 6

18 95 SFDR (dbc) 4 C 95 SFDR (dbc) +85 C SFDR (dbc) +5 C 9 SFDR (dbc) +5 C 9 SFDR (dbc) +85 C SFDR (dbc) 4 C (db) 8 SNR (db) +5 C SNR (db) 4 C (db) 8 SNR (db) +5 C SNR (db) 4 C SNR (db) +85 C ANALOG INPUT FREQUENCY (MHz) Figure 4. - SNR/SFDR vs. Analog Input Frequency, MSPS,. V p-p SNR (db) +85 C ANALOG INPUT FREQUENCY (MHz) Figure 7. - SNR/SFDR vs. Analog Input Frequency, MSPS,. V p-p (db) SFDR (dbc) +85 C SFDR (dbc) +5 C SFDR (dbc) 4 C SNR (db) +5 C SNR (db) 4 C (db) M SNR dbfs M SNR dbfs 75 SNR (db) +85 C ANALOG INPUT FREQUENCY (MHz) Figure 5. - SNR/SFDR vs. Analog Input Frequency, MSPS,. V p-p, CMOS Output Mode ANALOG INPUT RANGE (V p-p) Figure 8. - SNR vs. Input Range,. MHz, dbfs SFDR dbfs SFDR dbfs 8 SNR dbfs 9 7 SNR dbfs (db) 6 4 SFDR dbc (db) 5 SFDR dbc SNR db ANALOG INPUT AMPLITUDE (db) Figure 6. - SNR/SFDR vs. Analog Input Level, MSPS SNR db ANALOG INPUT AMPLITUDE (db) Figure 9. - SNR/SFDR vs. Analog Input Level, MSPS, CMOS Output Mode Rev. Page 8 of 6

19 95 SFDR (dbc) +85 C 95 SFDR (dbc) 4 C SFDR (dbc) 4 C SFDR (dbc) +5 C SNR (db) 4 C SFDR (dbc) +5 C SNR (db) 4 C SFDR (dbc) +85 C (db) 75 SNR (db) +85 C SNR (db) +5 C (db) 75 SNR (db) +5 C 7 7 SNR (db) +85 C ANALOG INPUT FREQUENCY (MHz) Figure. -8 SNR/SFDR vs. Analog Input Frequency, 8 MSPS,. V p-p ANALOG INPUT FREQUENCY (MHz) Figure. -8 SNR/SFDR vs. Analog Input Frequency, 8 MSPS,. V p-p SFDR (dbc) +5 C SFDR (dbc) 4 C SFDR (dbc) +85 C SFDR dbc (db) 8 75 SNR (db) +5 C SNR (db) +85 C SNR (db) 4 C (db) SNR db ANALOG INPUT FREQUENCY (MHz) Figure. -8 SNR/SFDR vs. Analog Input Frequency, 8 MSPS,. V p-p, CMOS Mode ANALOG INPUT COMMON-MODE VOLTAGE Figure SNR/SFDR vs. Analog Input Common Mode, 8 MSPS SFDR dbfs SFDR dbfs 8 SNR dbfs 8 SNR dbfs (db) 6 (db) 6 4 SFDR dbc 4 SFDR dbc SNR db ANALOG INPUT AMPLITUDE (db) Figure. -8 SNR/SFDR vs. Analog Input Level, 8 MSPS 549- SNR db ANALOG INPUT AMPLITUDE (db) Figure SNR/SFDR vs. Analog Input Level, 8 MSPS, CMOS Output Mode Rev. Page 9 of 6

20 AMPLITUDE (dbfs) MSPS 7.dBFS SFDR = 95dBc FREQUENCY (MHz) Figure k Point Two-Tone FFT/ MSPS/9.8 MHz,.8 MHz SFDR dbc 5 6 WORST IMD dbc SFDR dbfs WORST IMD dbfs FUNDAMENTAL LEVEL (db) Figure 9. - Two-Tone SFDR vs. Analog Input Level MSPS/ 69. MHz, 7. MHz SPUR AND IMD (db) SFDR dbc 6 WORST IMD dbc SFDR dbfs WORST IMD dbfs FUNDAMENTAL LEVEL (db) Figure 7. - Two-Tone SFDR vs. Analog Input Level MSPS/ 9.8 MHz,.8 MHz SPUR AND IMD (db) MSPS 7.dBFS SFDR = 96dBc FREQUENCY (MHz) Figure k Point Two-Tone FFT/8 MSPS/9.8 MHz,.8 MHz AMPLITUDE (dbfs) MSPS 7.dBFS 7.dBFS SFDR = 9dBc FREQUENCY (MHz) Figure k Point Two-Tone FFT/ MSPS/69. MHz, 7. MHz AMPLITUDE (dbfs) SFDR dbc 7 8 WORST IMD dbc 9 SFDR dbfs WORST IMD dbfs FUNDAMENTAL LEVEL (db) Figure Two-Tone SFDR vs. Analog Input Level 8 MSPS/ 9.8 MHz,.8 MHz SPUR AND IMD (db) Rev. Page of 6

21 6 4 SAMPLE SIZE = SAMPLE SIZE = FREQUENCY FREQUENCY N 7 N 6 N 5 N 4 N N N N N + N + N + N + 4 N + 5 N + 6 N + 7 OUTPUT CODE Figure 4. - Grounded Input Histogram N 6 N 5 N 4 N N N N N + N + N + N + 4 N + 5 N + 6 OUTPUT CODE Figure Grounded Input Histogram AMPLITUDE (dbfs) MSPS 7.dBFS 7.dBFS SFDR = 9dBc GAIN ERROR (%FSR) FREQUENCY (MHz) Figure k Point Two-Tone FFT/8 MSPS/69. MHz, 7. MHz TEMPERATURE ( C) Figure Gain vs. Temperature SFDR dbc 7 WORST IMD dbc 8 9 SFDR dbfs WORST IMD dbfs FUNDAMENTAL LEVEL (db) Figure Two-Tone SFDR vs. Analog Input Level 8 MSPS/ 69. MHz, 7. MHz SPUR AND IMD (db) I SUPPLY (ma) AVDD AVDD SAMPLE RATE (MSPS) Figure Power Supply Current vs. Sample Rate. dbfs Rev. Page of 6

22 MHz SFDR dbc (db) MHz SFDR dbc (db) 8 79.MHz SFDR dbc 7.MHz SFDR dbc MHz SFDR dbc ANALOG INPUT RANGE (V p-p) MHz SFDR dbc ANALOG INPUT RANGE (V p-p) Figure 48. -/SFDR vs. Analog Input Range, MSPS Figure 5. - SNR vs. Analog Input Range, MSPS MHz SFDR dbc.6 9 VREF.65 (db) MHz SFDR dbc MHz SFDR dbc TEMPERATURE ( C) ANALOG INPUT RANGE (V p-p) Figure VREF vs. Temperature Figure SFDR vs. Analog Input Range, MSPS MHz SNR db I SUPPLY (ma) AVDD AVDD (db) MHz SNR db.mhz SNR db SAMPLE RATE (MSPS) Figure 5. - Power Supply Current vs. Sample Rate. dbfs ANALOG INPUT RANGE (V p-p) Figure 5. -8/SNR vs. Analog Input Range, 8 MSPS Rev. Page of 6

23 95 M SFDR dbc 9 8M SFDR dbc (db) 85 8M SNR db 8 75 M SNR db SAMPLE RATE (MSPS) Figure 54. Single-Tone SNR/SFDR vs. Sample Rate. MHz Rev. Page of 6

24 THEORY OF OPERATION The architecture is optimized for high speed and ease of use. The analog inputs drive an integrated, high bandwidth track-and-hold circuit that samples the signal prior to quantization by the 6-bit pipeline ADC core. The device includes an on-board reference and input logic that accepts TTL, CMOS, or LVPECL levels. The digital output logic levels are user selectable as standard V CMOS or LVDS (ANSI-644 compatible) via the OUTPUT MODE pin. ANALOG INPUT AND REFERENCE OVERVIEW A stable and accurate.5 V band gap voltage reference is built into the. The input range can be adjusted by varying the reference voltage applied to the, using either the internal reference or an externally applied reference voltage. The input span of the ADC tracks reference voltage changes linearly. Internal Reference Connection A comparator within the detects the potential at the SENSE pin and configures the reference into three possible states, which are summarized in Table 9. If SENSE is grounded, the reference amplifier switch is connected to the internal resistor divider (see Figure 55), setting VREF to ~.6 V. If a resistor divider is connected as shown in Figure 56, the switch again sets to the SENSE pin. This puts the reference amplifier in a noninverting mode with the VREF output defined as R VREF =.5 V + R In all reference configurations, REFT and REFB drive the analog-to-digital conversion core and establish its input span. The input range of the ADC always equals twice the voltage at the reference pin for either an internal or an external reference. Internal Reference Trim The internal reference voltage is trimmed during the production test; therefore, there is little advantage to the user supplying an external voltage reference to the. The gain trim is performed with the input range set to. V p-p nominal (SENSE connected to ). Because of this trim and the maximum ac performance provided by the. V p-p analog input range, there is little benefit to using analog input ranges < V p-p. However, reducing the range can improve SFDR performance in some applications. Likewise, increasing the range up to.8 V p-p can improve SNR. Users are cautioned that the differential nonlinearity of the ADC varies with the reference voltage. Configurations that use <. V p-p may exhibit missing codes and therefore degraded noise and distortion performance. μf + μf +.μf.μf VIN+ VIN VREF SENSE SELECT LOGIC.5V ADC CORE REFT.μF.μF REFB Figure 55. Internal Reference Configuration VIN+ VIN VREF R SENSE SELECT LOGIC R.5V ADC CORE.μF REFT REFB.μF.μF.μF Figure 56. Programmable Reference Configuration + μf μf Rev. Page 4 of 6

25 Table 9. Reference Configuration Summary Selected Mode SENSE Voltage Resulting VREF (V) Resulting Differential Span (V p-p) External Reference AVDD N/A external reference Programmable Reference. V to VREF R VREF.5 + (See Figure 56) R Programmable Reference. V to VREF (Set for V p-p) R..5 +, R = R = kω R Programmable Reference. V to VREF (Set for V p-p) R.8.5 +, R = kω, R =.8 kω R Internal Fixed Reference to. V.6. External Reference Operation When the SENSE pin is tied to AVDD, the internal reference is disabled, allowing the use of an external reference. An internal reference buffer loads the external reference with an equivalent 7 kω load. The internal buffer still generates the positive and negative full-scale references, REFT and REFB, for the ADC core. The input span is always twice the value of the reference voltage; therefore, the external reference must be limited to a maximum of. V. See Figure 46 for gain variation vs. temperature..6v p-p VIN+ VIN DIGITAL OUT = ALL s DIGITAL OUT = ALL s.5v Analog Inputs As with most new high speed, high dynamic range ADCs, the analog input to the is differential. Differential inputs improve on-chip performance because signals are processed through attenuation and gain stages. Most of the improvement is a result of differential analog stages having high rejection of even-order harmonics. There are also benefits at the PCB level. First, differential inputs have high common-mode rejection of stray signals, such as ground and power noise. Second, they provide good rejection of common-mode signals, such as local oscillator feedthrough. The specified noise and distortion of the cannot be realized with a single-ended analog input, so such configurations are discouraged. Contact sales for recommendations of other 6-bit ADCs that support singleended analog input configurations. With the.6 V reference, which is the nominal value (see the Internal Reference Trim section), the differential input range of the analog input is nominally. V p-p or.6 V p-p on each input (VIN+ or VIN ). Figure 57. Differential Analog Input Range for VREF =.6 V The analog input voltage range is offset from ground by.5 V. Each analog input connects through a kω resistor to the.5 V bias voltage and to the input of a differential buffer. The internal bias network on the input properly biases the buffer for maximum linearity and range (see the Equivalent Circuits section). Therefore, the analog source driving the should be ac-coupled to the input pins. The recommended method for driving the analog input of the is to use an RF transformer to convert single-ended signals to differential (see Figure 58). Series resistors between the output of the transformer and the analog inputs help isolate the analog input source from switching transients caused by the internal sample-and-hold circuit. The series resistors, along with the kω resisters connected to the internal.5 V bias, must be considered in impedance matching the transformer input. For example, if RT is set to 5 Ω, RS is set to Ω and there is a : impedance ratio transformer, the input will match a 5 Ω source with a full-scale drive of 6. dbm. The 5 Ω impedance matching can also be incorporated on the secondary side of the transformer, as shown in the evaluation board schematic (see Figure 6) Rev. Page 5 of 6

26 ANALOG INPUT SIGNAL R T ADT WT.μF R S R S VIN+ VIN Figure 58. Transformer-Coupled Analog Input Circuit CLOCK INPUT CONSIDERATIONS Any high speed ADC is extremely sensitive to the quality of the sampling clock provided by the user. A track-and-hold circuit is essentially a mixer, and any noise, distortion, or timing jitter on the clock is combined with the desired signal at the analog-todigital output. For that reason, considerable care was taken in the design of the clock inputs of the, and the user is advised to give careful thought to the clock source. Typical high speed ADCs use both clock edges to generate a variety of internal timing signals and, as a result, may be sensitive to the clock duty cycle. Commonly a 5% tolerance is required on the clock duty cycle to maintain dynamic performance characteristics. The contains a clock duty cycle stabilizer (DCS) that retimes the nonsampling edge, providing an internal clock signal with a nominal ~5% duty cycle. Noise and distortion performance are nearly flat for a % to 7% duty cycle with the DCS enabled. The DCS circuit locks to the rising edge of CLK+ and optimizes timing internally. This allows for a wide range of input duty cycles at the input without degrading performance. Jitter in the rising edge of the input is still of paramount concern and is not reduced by the internal stabilization circuit. The duty cycle control loop does not function for clock rates of less than MHz nominally. The loop is associated with a time constant that should be considered in applications where the clock rate can change dynamically, requiring a wait time of.5 μs to 5 μs after a dynamic clock frequency increase or decrease before the DCS loop is relocked to the input signal. During the time that the loop is not locked, the DCS loop is bypassed, and the internal device timing is dependent on the duty cycle of the input clock signal. In such an application, it may be appropriate to disable the duty cycle stabilizer. In all other applications, enabling the DCS circuit is recommended to maximize ac performance. The DCS circuit is controlled by the DCS MODE pin; a CMOS logic low () on DCS MODE enables the duty cycle stabilizer, and logic high (AVDD =. V) disables the controller. The input sample clock signal must be a high quality, extremely low phase noise source to prevent degradation of performance. Maintaining 6-bit accuracy places a premium on the encode clock phase noise. SNR performance can easily degrade by db to 4 db with 7 MHz analog input signals when using a high jitter clock source. (See the AN-5 Application Note, Aperture Uncertainty and ADC System Performance. ) For optimum performance, the must be clocked differentially. The sample clock inputs are internally biased to ~.5 V, and the input signal is usually ac-coupled into the CLK+ and CLK pins via a transformer or capacitors. Figure 59 shows one preferred method for clocking the. The clock source (low jitter) is converted from single-ended to differential using an RF transformer. The back-to-back Schottky diodes across the secondary of the transformer limit clock excursions into the to approximately.8 V p-p differential. This helps prevent the large voltage swings of the clock from feeding through to other portions of the and limits the noise presented to the sample clock inputs. If a low jitter clock is available, it may help to band-pass filter the clock reference before driving the ADC clock inputs. Another option is to ac couple a differential ECL/PECL signal to the encode input pins, as shown in Figure 6. CRYSTAL SINE SOURCE.μF ADT WT HSMS8 DIODES CLK+ CLK Figure 59. Crystal Clock Oscillator, Differential Encode ECL/ PECL Jitter Considerations VT VT.μF.μF ENCODE ENCODE Figure 6. Differential ECL for Encode High speed, high resolution ADCs are sensitive to the quality of the clock input. The degradation in SNR at a given input frequency (finput) and rms amplitude due only to aperture jitter (tj) can be calculated using the following equation: SNR = log[πfinput tj] In the equation, the rms aperture jitter represents the root-meansquare of all jitter sources, which includes the clock input, analog input signal, and ADC aperture jitter specification. IF undersampling applications are particularly sensitive to jitter The clock input should be treated as an analog signal in cases where aperture jitter may affect the dynamic range of the. Power supplies for clock drivers should be separated from the ADC output driver supplies to avoid modulating the clock signal with digital noise. Low jitter crystal-controlled oscillators make the best clock sources. If the clock is generated from another type of source (by gating, dividing, or another method), it should be synchronized by the original clock during the last step Rev. Page 6 of 6

27 POWER CONSIDERATIONS Care should be taken when selecting a power source. The use of linear dc supplies is highly recommended. Switching supplies tend to have radiated components that may be received by the. Each of the power supply pins should be decoupled as closely to the package as possible using. μf chip capacitors. The has separate digital and analog power supply pins. The analog supplies are denoted AVDD (. V) and AVDD (5 V), and the digital supply pins are denoted. Although the AVDD and supplies can be tied together, best performance is achieved when the supplies are separate. This is because the fast digital output swings can couple switching current back into the analog supplies. Note that both AVDD and AVDD must be held within 5% of the specified voltage. The supply of the is a dedicated supply for the digital outputs in either LVDS or CMOS output mode. When in LVDS mode, the should be set to. V. In CMOS mode, the supply can be connected from.5 V to.6 V for compatibility with the receiving logic. DIGITAL OUTPUTS LVDS Mode The off-chip drivers on the chip can be configured to provide LVDS-compatible output levels via Pin (OUTPUT MODE). LVDS outputs are available when OUTPUT MODE is CMOS logic high (or AVDD for convenience) and a.74 kω RSET resistor is placed at Pin 5 (LVDS_BIAS) to ground. Dynamic performance, including both SFDR and SNR, is maximized when the is used in LVDS mode; designers are encouraged to take advantage of this mode. The outputs include complimentary LVDS outputs for each data bit (Dx+/Dx ), the overrange output (OR+/OR ), and the output data clock output (DCO+/DCO ). The RSET resistor current is multiplied on-chip, setting the output current at each output equal to a nominal.5 ma ( IR SET ). A Ω differential termination resistor placed at the LVDS receiver inputs results in a nominal 5 mv swing at the receiver. LVDS mode facilitates interfacing with LVDS receivers in custom ASICs and FPGAs that have LVDS capability for superior switching performance in noisy environments. Single point-to-point net topologies are recommended, with a Ω termination resistor located as close to the receiver as possible. It is recommended to keep the trace length less than inches and to keep differential output trace lengths as equal as possible. CMOS Mode In applications that can tolerate a slight degradation in dynamic performance, the output drivers can be configured to interface with.5 V or. V logic families by matching to the digital supply of the interfaced logic. CMOS outputs are available when OUTPUT MODE is CMOS logic low (or for convenience). In this mode, the output data bits, Dx, are single-ended CMOS, as is the overrange output, OR+. The output clock is provided as a differential CMOS signal, DCO+/DCO. Lower supply voltages are recommended to avoid coupling switching transients back to the sensitive analog sections of the ADC. The capacitive load to the CMOS outputs should be minimized, and each output should be connected to a single gate through a series resistor ( Ω) to minimize switching transients caused by the capacitive loading. TIMING The provides latched data outputs with a pipeline delay of clock cycles. Data outputs are available one propagation delay (tpd) after the rising edge of CLK+. Refer to Figure and Figure for detailed timing diagrams. Rev. Page 7 of 6

28 OPERATIONAL MODE SELECTION Data Format Select The data format select (DFS) pin of the determines the coding format of the output data. This pin is. V CMOS compatible, with logic high (or AVDD,. V) selecting twos complement and DFS logic low () selecting offset binary format. Table summarizes the output coding. Output Mode Select The OUPUT MODE pin controls the logic compatibility, as well as the pinout of the digital outputs. This pin is a CMOScompatible input. With OUTPUT MODE = (), the outputs are CMOS compatible, and the pin assignment for the device is as defined in Table 8. With OUTPUT MODE = (AVDD,. V), the outputs are LVDS compatible, and the pin assignment for the device is as defined in Table 7. Duty Cycle Stabilizer The DCS circuit is controlled by the DCS MODE pin; a CMOS logic low () on DCS MODE enables the DCS, and logic high (AVDD,. V) disables the controller. Table. Digital Output Coding VIN+ VIN Code Input Span =. V p-p (V) VIN+ VIN Input Span = V p-p (V) Digital Output Offset Binary (D5 D) Digital Output Twos Complement (D5 D) 65, ,768, Rev. Page 8 of 6

29 EVALUATION BOARD Evaluation boards are offered to configure the in either CMOS or LVDS mode only. This design represents a recommended configuration for using the device over a wide range of sampling rates and analog input frequencies. These evaluation boards provide all the support circuitry required to operate the ADC in its various modes and configurations. Complete schematics are shown in Figure 6 through Figure 64. Gerber files are available from engineering applications demonstrating the proper routing and grounding techniques that should be applied at the system level. It is critical that signal sources with very low phase noise (<6 fsec rms jitter) be used to realize the ultimate performance of the converter. Proper filtering of the input signal to remove harmonics and lower the integrated noise at the input is also necessary to achieve the specified noise performance. The evaluation boards are shipped with a 5 V ac to 6 V dc power supply. The evaluation boards include low dropout regulators to generate the various dc supplies required by the and its support circuitry. Separate power supplies are provided to isolate the DUT from the support circuitry. Each input configuration can be selected by proper connection of various jumpers (see Figure 6). The LVDS mode evaluation boards include an LVDS-to-CMOS translator, making them compatible with the high speed ADC FIFO evaluation kit (HSC-ADC-EVALA-SC). The kit includes a high speed data capture board that provides a hardware solution for capturing up to kb samples of high speed ADC output data in a FIFO memory chip (user upgradeable to 56 kb samples). Software is provided to enable the user to download the captured data to a PC via the USB port. This software also includes a behavioral model of the and many other high speed ADCs. Behavioral modeling of the is also available at The ADIsimADC software supports virtual ADC evaluation using ADI proprietary behavioral modeling technology. This allows rapid comparison between the and other high speed ADCs with or without hardware evaluation boards. The user can choose to remove the translator and terminations to access the LVDS outputs directly. Rev. Page 9 of 6

30 Rev. Page of 6 OPTIONAL R kω R.74kΩ E4 EXTREF D_C (LSB) D_T D_C D_T D_C D_T D4_C D4_T D5_C D5_T D7_C D7_T DR D8_C/D_Y D8_T/D_Y D9_C/D_Y D9_T/D_Y D_C/D4_Y C98 DNP D5_C/D4_Y E4 E5 E7 E6 E6 E5 E4 C.μF C9.μF C86.μF R DNP 5V D4_C/D_Y D6_T D_T D_T/D_Y D_T/D5_Y DRB D6_C D_C D4_T/D_Y D_C/D_Y D_T/D9_Y D_C/D8_Y D_T/D7_Y D_C/D6_Y 5V ENCB ENC 5V 5V 5V 5V 5V 5V 5V SCLK 5V C DNP R5 Ω R8 Ω R9 DNP C9.μF C8.μF EPAD AD9445/ U R4 6Ω P P P P PTMICRO4 5V P4 4 P P P P PTMICRO4 EXTREF XTALPWR P4 4 DCS MODE DNC OUTPUT MODE DFS LVDSBIAS AVDD SENSE VREF REFT REFB AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD VIN+ VIN AVDD DOR_C DOR_T/DOR_Y (MSB) D5_T/D5_Y E E9 E E4 E E E66 E8 E9 C.μF C5.μF J4 SMBMST R5 DNP TINB ANALOG L nh E5 R6 6Ω R DNP C5 μf C.μF C4.μF D_T D_C D9_T D9_C D8_T D8_C DCO DCOB D7_T D7_C D6_T D6_C D5_T D5_C D4_T D4_C D_T D_C D_T D_C D_T D_C D_T D_C D_T D_C AVDD AVDD AVDD AVDD OR_C OR_T AVDD AVDD D5_T D5_C D4_T D4_C D_T D_C AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD AVDD ENC ENCB AVDD AVDD AVDD D_C D_T H4 MTHOLE6 H MTHOLE6 H MTHOLE6 H MTHOLE6 C9 μf + TOUT CT TOUTB C7.μF PRI SEC T5 ADT-WT T NC TINB TOUTB TOUT CT PRI SEC ETC PRI SEC T ETC Figure 6. Evaluation Board Schematic