8-Bit, 250 MSPS 3.3 V A/D Converter AD9480 FUNCTIONAL BLOCK DIAGRAM DNL = ± 0.25 LSB INL = ± 0.26 LSB Single 3.3 V supply operation (3.0 V to 3.6 V) Power dissipation of 590 mW at 250 MSPS 1 V p-p analog input range Internal 1.0 V reference Single-ended or differential analog inputs LVDS outputs (ANSI 644 levels) Power-down mode Clock duty-cycle stabilizer VREF SENSE AGND DrGND T&H VIN– CLK+ CLK– 8-BIT ADC PIPELINE CORE 8 CLOCK MGMT LVDS 16 D7–D0 (LVDS) DCO+ DCOLOGIC APPLICATIONS Digital oscilloscopes Instrumentation and measurement Communications Point-to-point radios Predistortion loops AVDD AD9480 REFERENCE VIN+ DRVDD PDWN S1 (LVDS) LVDSBIAS 04619-001 FEATURES Figure 1. GENERAL DESCRIPTION PRODUCT HIGHLIGHTS The AD9480 is an 8-bit, monolithic analog-to-digital converter (ADC) optimized for high speed and low power consumption. Small in size and easy to use, the product operates at a 250 MSPS conversion rate, with excellent linearity and dynamic performance over its full operating range. 1. Superior linearity. A DNL of ±0.25 makes the AD9480 suitable for instrumentation and measurement applications. 2. Power-down mode. A power-down function may be exercised to bring total consumption down to 15 mW. 3. LVDS outputs (ANSI-644). LVDS outputs simplify timing and improve noise performance To minimize system cost and power dissipation, the AD9480 includes an internal reference and track-and-hold circuit. The user only provides a 3.3 V power supply and a differential encode clock. No external reference or driver components are required for many applications. The digital outputs are LVDS (ANSI 644) compatible with an option of twos complement or binary output format. The output data bits are provided in parallel fashion along with an LVDS output clock, which simplifies data capture. Fabricated on an advanced BiCMOS process, the AD9480 is available in a 44-lead surface-mount package (TQFP) specified over the industrial temperature range −40°C to +85°C. Rev. A 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 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2005 Analog Devices, Inc. All rights reserved. AD9480 TABLE OF CONTENTS DC Specifications ............................................................................. 3 Interleaving Two AD9480s........................................................ 18 Digital Specifications........................................................................ 4 Data Clock Out........................................................................... 18 AC Specifications.............................................................................. 5 Power-Down ............................................................................... 18 Switching Specifications .................................................................. 6 AD9480 Evaluation Board ............................................................ 19 Timing Diagram ........................................................................... 6 Power Connector........................................................................ 19 Absolute Maximum Ratings............................................................ 7 Analog Inputs ............................................................................. 19 Explanation of Test Levels ........................................................... 7 Gain.............................................................................................. 19 ESD Caution.................................................................................. 7 Optional Operational Amplifier .............................................. 19 Pin Configuration and Function Descriptions............................. 8 Clock ............................................................................................ 19 Terminology ...................................................................................... 9 Optional Clock Buffer ............................................................... 19 Typical Performance Characteristics ........................................... 11 Optional XTAL ........................................................................... 19 Equivalent Circuits ......................................................................... 15 Voltage Reference ....................................................................... 20 Application Notes ........................................................................... 16 Data Outputs............................................................................... 20 Clocking the AD9480 ................................................................ 16 Evaluation Board Bill of Materials (BOM) ................................. 21 Analog Inputs.............................................................................. 16 PCB Schematics .............................................................................. 22 Voltage Reference ....................................................................... 17 PCB Layers ...................................................................................... 24 Digital Outputs ........................................................................... 18 Outline Dimensions ....................................................................... 26 Output Coding............................................................................ 18 Ordering Guide .......................................................................... 26 REVISION HISTORY 4/05—Rev. 0 to Rev. A Updated Format..................................................................Universal Changes to Features.......................................................................... 1 Changes to Table 3............................................................................ 5 Changes to Table 7............................................................................ 8 Changes to Analog Inputs ............................................................. 16 Changes to Figure 30...................................................................... 16 Added Power Down Section ......................................................... 18 Changes to Table 12........................................................................ 21 7/04—Revision 0: Initial Version Rev. A | Page 2 of 28 AD9480 DC SPECIFICATIONS AVDD = 3.3 V, DRVDD = 3.3 V, TMIN = −40°C, TMAX = +85°C, AIN = −1 dBFS, full scale = 1.0 V, internal reference, differential analog and clock inputs, unless otherwise noted. Table 1. Parameter RESOLUTION ACCURACY No Missing Codes Offset Error Gain Error1 Differential Nonlinearity (DNL) AD9480BSUZ-250 AD9480ASUZ-250 Integral Nonlinearity (INL) TEMPERATURE DRIFT Offset Error Gain Error Reference REFERENCE Internal Reference Voltage Output Current2 IVREF Input Current3 ISENSE Input Current2 ANALOG INPUTS (VIN+, VIN−) Differential Input Voltage Range (FS = 1) 4 Common-Mode Voltage Input Resistance Input Capacitance Analog Bandwidth, Full Power POWER SUPPLY AVDD DRVDD Power Dissipation5 Power-Down Dissipation IAVDD5 IDRVDD5 Power Supply Rejection Ratio (PSRR) Temp Test Level Min Full 25°C 25°C VI I I −40 −6.0 Full Full Full VI VI VI −0.5 −0.85 −0.9 Full Full Full V V V Full 25°C 25°C 25°C VI IV I I Full Full 25°C Full 25°C 25°C V VI I VI V V Full Full 25°C 25°C Full Full 25°C IV IV V V VI VI V 1 AD9480-250 Typ 8 Max Unit Bits +40 +6.0 mV % FS +0.5 +0.85 +0.9 LSB LSB LSB Guaranteed ±0.28 ±0.35 ±0.26 30 0.03 ±0.025 0.97 1.7 8.6 8.4 3.0 3.0 1.0 1 1.9 10 10 4 750 3.3 3.3 590 15 145 34 −4.2 µV/°C %FS/°C mV/°C 1.03 1.5 100 10 2.1 10.7 11.2 3.6 3.6 156 38 Gain error and gain temperature coefficients are based on the ADC only (with a fixed 1 V external reference and a 1 V p-p differential analog input). Internal reference mode; SENSE = AGND. 3 External reference mode; VREF driven by external 1.0 V reference; SENSE = AVDD. 4 In FS = 1 V, both analog inputs are 500 mV p-p and out of phase with each other. 5 Power dissipation and current measured with rated encode and a dc analog input (outputs static). See Figure 13 for active operation. 2 Rev. A | Page 3 of 28 V mA µA µA V p-p V kΩ kΩ pF MHz V V mW mW mA mA mV/V AD9480 DIGITAL SPECIFICATIONS AVDD = 3.3 V, DRVDD = 3.3 V, TMIN = −40°C, TMAX = +85°C, AIN = −1 dBFS, full scale = 1.0 V, internal reference, differential analog and clock inputs, unless otherwise noted. Table 2. Parameter CLOCK INPUTS (CLK+, CLK−) Differential Input Common-Mode Voltage1 Input Resistance Input Capacitance LOGIC INPUTS (PDWN, S1) 2 PDWN Logic 1 Voltage PDWN Logic 0 Voltage PDWN Logic 1 Input Current PDWN Logic 0 input Current PDWN, S1 Input Resistance PDWN, S1 Input Capacitance DIGITAL OUTPUTS Differential Output Voltage (VOD)3 Output Offset Voltage (VOS) Output Coding Temp Test Level Min Full Full Full 25°C IV VI VI V 200 1.4 4.2 Full Full Full Full 25°C 25°C IV IV VI VI V V 2.0 Full Full Full VI VI IV 247 1.125 1 The common mode for CLOCK inputs can be externally set, such that 0.9 V < CLK ± < 2.6 V. S1 is a multilevel logic input, see Table 8. 3 LVDSBIAS resistor = 3.74 kΩ. 2 Rev. A | Page 4 of 28 AD9480-250 Typ Max 1.5 5.5 4 1.68 6.0 0.8 ±160 10 30 4 454 1.375 Twos complement or binary Unit mV p-p V kΩ pF V V µA µA kΩ pF mV V AD9480 AC SPECIFICATIONS AVDD = 3.3 V, DRVDD = 3.3 V, TMIN = –40°C, TMAX = +85°C, AIN = –1 dBFS, full scale = 1.0 V, internal reference, differential analog and clock inputs, unless otherwise noted. Table 3. Parameter SIGNAL-TO-NOISE RATIO (SNR) fIN = 19.7 MHz fIN = 70.1 MHz fIN = 170 MHz SIGNAL-TO-NOISE AND DISTORTION (SINAD) fIN = 19.7 MHz fIN = 70.1 MHz fIN = 170 MHz EFFECTIVE NUMBER OF BITS (ENOB) fIN = 19.7 MHz fIN = 70.1 MHz fIN = 170 MHz WORST SECOND OR THIRD HARMONIC DISTORTION fIN = 19.7 MHz fIN = 70.1 MHz fIN = 170 MHz WORST OTHER fIN = 19.7 MHz fIN = 70.1 MHz fIN = 170 MHz SPURIOUS-FREE DYNAMIC RANGE (SFDR)1 fIN = 19.7 MHz fIN = 70.1 MHz fIN = 170 MHz TWO-TONE INTERMODULATION DISTORTION (IMD) fIN1 = 69.3 MHz, fIN2 = 70.3 MHz 1 AD9480-250 Typ Max Temp Test Level Min 25°C 25°C 25°C V I I 45 45 47 47 46 dB dB dB 25°C 25°C 25°C V I I 44.8 44.8 46.5 46.5 46.5 dB dB dB 25°C 25°C 25°C V I I 7.3 7.3 7.6 7.6 7.6 Bits Bits Bits 25°C 25°C 25°C V I I −65 −65 −65 −60 −60 dBc dBc dBc 25°C 25°C 25°C V I I −70 −70 −70 −63 −63 dBc dBc dBc 25°C 25°C 25°C V I I −65 −65 −65 −60 −60 dBc dBc dBc 25°C V −68 Nyquist bin energy ignored. Rev. A | Page 5 of 28 Unit dBc AD9480 SWITCHING SPECIFICATIONS AVDD = 3.3 V, DRVDD = 3.3 V, differential clock input, DCS enabled, unless otherwise noted. Table 4. Parameter CLOCK Maximum Conversion Rate Minimum Conversion Rate Clock Pulse Width High (tEH) Clock Pulse Width Low (tEL) OUTPUT PARAMETERS Valid Time (tV)1 Propagation Delay (tPD) Rise Time (tR) 20% to 80% Fall Time (tF) 20% to 80% DCO Propagation Delay (tCPD) Data-to-DCO Skew (tPD − tCPD) Pipeline Latency APERTURE Aperture Delay (tA) Aperture Uncertainty (Jitter) 1 Temp Test Level Min Full Full Full Full VI VI IV IV 250 Full Full Full Full Full Full 25°C VI VI V V VI IV VI 25°C 25°C V V AD9480-250 Typ Max Unit MSPS MSPS ns ns 20 1.2 1.2 2 2 1.9 2.8 0.5 0.5 2.7 0.1 8 1.9 0 ns ns ns ns ns ns Cycles 3.8 3.7 0.6 1.5 0.25 ns ps rms Valid time is approximately equal to minimum tPD. CLOAD equals 5 pF maximum. TIMING DIAGRAM N–1 tA N+10 N+11 N N+9 AIN N+1 N+8 8 CYCLES tEH tEL 1/fS CLK+ CLK– tPD tV DATA N–8 OUT N–7 N N+1 N+2 tCPD 04619-002 DCO+ DCO– Figure 2. Timing Diagram Rev. A | Page 6 of 28 AD9480 ABSOLUTE MAXIMUM RATINGS Thermal impedance (θJA) = 46.4°C/W (4-layer PCB). Table 5. Parameter ELECTRICAL AVDD (With Respect to AGND) DRVDD (With Respect to DRGND) AGND (With Respect to DRGND) Digital I/O (With Respect to DRGND) Analog Inputs (With Respect to AGND) ENVIRONMENTAL Operating Temperature Junction Temperature Case Temperature Storage Temperature Min Rating Max Rating −0.5 V +4.0 V −0.5 V +4.0 V −0.5 V +0.5 V −0.5 V DRVDD + 0.5 V −0.5 V AVDD + 0.5 V −40°C 85°C 150°C 150°C 150°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. EXPLANATION OF TEST LEVELS Table 6. Level I II III IV V VI Descriptions 100% production tested. 100% production tested at 25°C and guaranteed by design and characterization at specified temperatures. Sample tested only. Parameter is guaranteed by design and characterization testing. Parameter is a typical value only. 100% production tested at 25°C and guaranteed by design and characterization for industrial temperature range. ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 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. A | Page 7 of 28 AD9480 VREF AGND AVDD AGND VIN– VIN+ AGND AVDD LVDSBIAS NC AGND PIN CONFIGURATION AND FUNCTION DESCRIPTIONS 44 43 42 41 40 39 38 37 36 35 34 CLK+ 1 PIN 1 CLK– 2 33 SENSE 32 AGND AVDD 3 31 AVDD AGND 4 30 AGND 29 PDWN 28 S1 D0_C (LSB) 7 27 DRGND D0_T (LSB) 8 26 D7_T (MSB) D1_C 9 25 D7_C (MSB) D1_T 10 24 D6_T 23 D6_C AD9480 DRVDD 5 TOP VIEW (Not to Scale) DRGND 6 D2_C 11 04619-003 D5_T D5_C D4_T D4_C DRVDD DCO+ DCO– DRGND D3_T D2_T D3_C NC = NO CONNECT 12 13 14 15 16 17 18 19 20 21 22 Figure 3. Pin Configuration Table 7. Pin Function Descriptions Pin No. 1 2 3 4 5 6 Mnemonic CLK+ CLK− AVDD AGND DRVDD DRGND Description Input Clock—True Input Clock—Complement 3.3 V Analog Supply Analog Ground 3.3 V Digital Output Supply Digital Ground Pin No. 23 24 25 26 27 28 Mnemonic D6_C D6_T D7_C D7_T DRGND S1 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 D0_C D0_T D1_C D1_T D2_C D2_T D3_C D3_T DRGND DCO− DCO+ DRVDD D4_C D4_T D5_C D5_T Data Output Bit 0—Complement (LSB) Data Output Bit 0—True (LSB) Data Output Bit 1—Complement Data Output Bit 1—True Data Output Bit 2—Complement Data Output Bit 2—True Data Output Bit 3—Complement Data Output Bit 3—True Digital Ground Data Clock Output—Complement Data Clock Output—True 3.3 V Digital Output Supply Data Output Bit 4—Complement Data Output Bit 4—True Data Output Bit 5—Complement Data Output Bit 5—True 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 PDWN AGND AVDD AGND SENSE VREF AGND AVDD AGND VIN− VIN+ AGND AVDD LVDSBIAS NC1 AGND 1 Description Data Output Bit 6—Complement Data Output Bit 6—True Data Output Bit 7—Complement (MSB) Data Output Bit 7—True (MSB) Digital Ground Data Format Select and Duty-Cycle Stabilizer Selection (See Table 8) Power-Down Selection (AVDD = Power Down) Analog Ground 3.3 V Analog Supply Analog Ground Reference Mode Selection (See Table 9) Voltage Reference Input/Output Analog Ground 3.3 V Analog Supply Analog Ground Analog Input—Complement Analog Input—True Analog Ground 3.3 V Analog Supply LVDS Output Current Adjust No Connect (Leave Floating) Analog Ground Pin 43 will self-bias to 1.5 V. It can be left floating (as recommended) or tied to AVDD or ground with no ill effects. Rev. A | Page 8 of 28 AD9480 TERMINOLOGY Analog Bandwidth The analog input frequency at which the spectral power of the fundamental frequency (as determined by the FFT analysis) is reduced by 3 dB. Full-Scale Input Power Expressed in dBm. Computed by ⎛ V 2 FULLSCALE rms ⎜ ⎜ Z INPUT PowerFULLSCALE = 10 log ⎜ 0.001 ⎜ ⎜ ⎝ Aperture Delay The delay between the 50% point of the rising edge of the encode command and the instant the analog input is sampled. Gain Error The difference between the measured and ideal full-scale input voltage range of the ADC. Aperture Uncertainty (Jitter) The sample-to-sample variation in aperture delay. Clock Pulse Width/Duty Cycle Pulse width high is the minimum amount of time that the clock pulse should be left in a Logic 1 state to achieve rated performance; pulse width low is the minimum time that the clock pulse should be left in a low state. See the timing implications of changing tEH in the Clocking the AD9480 section. At a given clock rate, these specifications define an acceptable clock duty cycle. Harmonic Distortion, Second The ratio of the rms signal amplitude to the rms value of the second harmonic component, reported in dBc. Harmonic Distortion, Third The ratio of the rms signal amplitude to the rms value of the third harmonic component, reported in dBc. Integral Nonlinearity The deviation of the transfer function from a reference line measured in fractions of 1 LSB using a best straight line determined by a least square curve fit. Crosstalk Coupling onto one channel being driven by a low level (−40 dBFS) signal when the adjacent interfering channel is driven by a full-scale signal. Differential Analog Input Resistance, Differential Analog Input Capacitance, and Differential Analog Input Impedance The real and complex impedances measured at each analog input port. The resistance is measured statically, and the capacitance and differential input impedances are measured with a network analyzer. Differential Analog Input Voltage Range The peak-to-peak differential voltage that must be applied to the converter to generate a full-scale response. Peak differential voltage is computed by observing the voltage on a single pin and subtracting the voltage from the other pin, which is 180° out of phase. Peak-to-peak differential is computed by rotating the inputs phase 180° and taking the peak measurement again. The difference is then computed between both peak measurements. Differential Nonlinearity The deviation of any code width from an ideal 1 LSB step. Effective Number of Bits The effective number of bits (ENOB) is calculated by the measured SINAD based on (assuming full-scale input) ENOB = SINAD MEASURED − 1.76 dB 6.02 ⎞ ⎟ ⎟ ⎟ ⎟ ⎟ ⎠ Minimum Conversion Rate The encode rate at which the SNR of the lowest analog signal frequency drops by no more than 3 dB below the guaranteed limit. Maximum Conversion Rate The encode rate at which parametric testing is performed. Output Propagation Delay The delay between a differential crossing of CLK+ and CLK− and the time when all output data bits are within valid logic levels. Noise (For Any Range Within the ADC) This value includes both thermal and quantization noise. − SNRdBc − SignaldBFS ⎛ FS Vnoise = Z × .001× 10 ⎜⎜ dBm 10 ⎝ ⎞ ⎟⎟ ⎠ where: Z is the input impedance. FS is the full scale of the device for the frequency in question. SNR is the value for the particular input level. Signal is the signal level within the ADC reported in dB below full scale. Power Supply Rejection Ratio The ratio of a change in input offset voltage to a change in power supply voltage. Rev. A | Page 9 of 28 AD9480 Signal-to-Noise and Distortion (SINAD) The ratio of the rms signal amplitude (set 1 dB below full scale) to the rms value of the sum of all other spectral components, including harmonics, but excluding dc. Signal-to-Noise Ratio (Without Harmonics) The ratio of the rms signal amplitude (set at 1 dB below full scale) to the rms value of the sum of all other spectral components, excluding the first five 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 or may not be a harmonic. It also may be reported in dBc (that is, degrades as signal level is lowered) or dBFS (that is, always related back to converter full scale). Two-Tone Intermodulation Distortion Rejection The ratio of the rms value of either input tone to the rms value of the worst third-order intermodulation product in dBc. 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. It also may be reported in dBc (that is, degrades as signal level is lowered) or in dBFS (that is, always relates back to converter full scale). Worst Other Spur The ratio of the rms signal amplitude to the rms value of the worst spurious component (excluding the second and third harmonic), reported in dBc. Transient Response Time The time it takes for the ADC to reacquire the analog input after a transient from 10% above negative full scale to 10% below positive full scale. Out-of-Range Recovery Time The time it takes for the ADC to reacquire the analog input after a transient from 10% above positive full scale to 10% above negative full scale, or from 10% below negative full scale to 10% below positive full scale. Rev. A | Page 10 of 28 AD9480 TYPICAL PERFORMANCE CHARACTERISTICS AVDD, DRVDD = 3.3 V, T = 25°C, AIN differential drive, FS = 1, unless otherwise noted. 0 0 SNR = 46.2dB H2 = 72.8dBc H3 = 73.2dBc SFDR = 69.8dBc –20 –30 –40 –40 dB –30 –50 –50 –60 –60 –70 –70 04619-020 dB –20 –80 –90 0 20 40 60 MHz 80 100 SNR = 45.9dB H2 = 71.9dBc H3 = 67dBc SFDR = 67dBc –10 04619-023 –10 –80 –90 120 0 Figure 4. FFT: fS = 250 MSPS, AIN = 10.3 MHz @ −1 dBFS 20 40 60 MHz 80 100 120 Figure 7. FFT: fS = 250 MSPS, AIN = 170 MHz @ −1 dBFS 90 0 SNR = 46.1dB H2 = 71.4dBc H3 = 74.3dBc SFDR = 68.7dBc –10 –20 85 H3 80 75 –30 dB dB 70 –40 H2 SFDR 65 –50 60 –60 55 –70 –90 0 20 40 60 MHz 80 100 SNR 45 SINAD 40 120 0 Figure 5. FFT: fS = 250 MSPS, AIN = 70 MHz @ –1 dBFS 04619-024 04619-021 50 –80 50 100 150 200 250 AIN (MHz) 300 350 400 Figure 8. Analog Input Frequency Sweep, AIN = −1 dBFS, FS = 1 V, fS = 250 MSPS 0 80 SNR = 45.9dB H2 = 67dBc H3 = 73.3dBc SFDR = 67dBc –10 –20 H3 75 H2 70 –30 SFDR dB dB 65 –40 60 –50 55 –60 04619-022 –80 –90 0 20 40 60 MHz 80 100 120 Figure 6. FFT: fS = 250 MSPS, AIN = 70 MHz @ –1 dBFS, Single-Ended Input Rev. A | Page 11 of 28 SNR 45 SINAD 40 0 50 100 150 200 250 AIN (MHz) 300 350 Figure 9. Analog Input Frequency Sweep, AIN = −1 dBFS, FS = 0.75 V, fS = 250 MSPS 04619-025 50 –70 400 AD9480 180 75 160 70 140 CURRENT IN mA 65 SFDR dB 60 55 120 IAVDD 100 80 60 50 SINAD 40 0 50 100 150 200 SAMPLE CLOCK (MHz) 250 20 0 0 300 Figure 10. SNR, SINAD, SFDR vs. Sample Clock Frequency, AIN = 70 MHz @ −1 dBFS 04619-029 04619-026 45 IDRVDD 40 SNR 50 100 150 200 ENCODE (MSPS) 250 300 Figure 13. IAVDD and IDRVDD vs. Clock Rate, CLOAD = 5 pF AIN = 70 MHz @ –1 dBFS 50 80 49 70 SFDRdBFS 48 DCS ON 60 47 46 dB dB 50 40 45 44 30 DCS OFF 43 20 04619-027 –50 –40 –30 –20 –10 ANALOG INPUT DRIVE LEVEL (dBFS) 40 20 0 Figure 11. SFDR vs. AIN Input Level; AIN = 70 MHz @ 250 MSPS 40 50 60 70 CLOCK POSITIVE DUTY CYCLE (%) 80 50.0 F1, F2 = –7dBFS 2F2-F1 = –71.1dBc 2F1-F2 = –68dBc –10 80 Figure 14. SNR, SINAD vs. Clock Pulse Width High, AIN = 70 MHz @ –1 dBFS, 250 MSPS, DCS On/Off 0 SNR –20 SNR, SINAD dB 47.5 –30 –40 –50 –60 75 SINAD 70 45.0 SFDR 65 42.5 –70 04619-028 dB 30 –80 –90 0 20 40 60 MHz 80 100 120 Figure 12. Two-Tone Intermodulation Distortion (69.3 MHz and 70.3 MHz; fS = 250 MSPS) 40.0 0.5 0.7 0.9 1.1 1.3 1.5 1.7 EXTERNAL VREF VOLTAGE (V) 1.9 50 Figure 15. SNR, SINAD, and SFDR vs. VREF in External Reference Mode, AIN = 70 MHz @ –1 dBFS, 250 MSPS Rev. A | Page 12 of 28 SFDR dB –60 41 04619-031 0 –70 65dB REF LINE 046190-030 42 SFDRdBc 10 AD9480 3 70 FS = 1V EXT REF SFDR 65 1 60 FS = 1V INT REF dB 0 55 –1 SNR 50 04619-032 –2 –3 –40 –20 0 20 40 TEMPERATURE (°C) 60 45 SINAD 3.0 3.1 80 Figure 16. Full-Scale Gain Error vs. Temperature, AIN = 70.3 MHz @ −0.5 dBFS, 250 MSPS, FS = 1 04619-035 GAIN ERROR (%) 2 3.2 3.3 AVDD (V) 3.4 3.5 3.6 Figure 19. SNR, SINAD, and SFDR vs. Supply Voltage, AIN = 70.3 MHz @ −1 dBFS, 250 MSPS 0.5 75 SFDR 1V INT REF 0.4 70 0.3 65 0.2 0.1 dB LSB 60 55 0 –0.1 –0.2 50 SINAD 1V INT REF 04619-033 40 –40 –20 0 20 40 TEMPERATURE (°C) 60 04619-036 –0.3 45 –0.4 –0.5 80 0 50 100 150 200 250 CODE Figure 17. SINAD, SFDR vs. Temperature, AIN = 70 MHz @ −1 dBFS, 250 MSPS Figure 20. Typical DNL Plot, AIN = 10.3 MHz @ –0.5 dBFS, 250 MSPS 0.10 0.50 0.05 LSB 0 0 –0.05 –0.25 –0.15 2.7 2.8 2.9 3.0 3.1 3.2 AVDD (V) 3.3 3.4 3.5 3.6 04619-037 –0.10 04619-034 CHANGE IN VREF (%) 0.25 –0.50 0 50 100 150 200 250 CODE Figure 18. VREF Sensitivity to AVDD Figure 21. Typical INL Plot, AIN = 10.3 MHz @ −0.5 dBFS, 250 MSPS Rev. A | Page 13 of 28 AD9480 0.30 900 800 0.25 1.3 VOS 700 1.2 600 1.1 500 1.0 0.10 0.05 0 –0.05 –0.10 –40 –20 0 20 40 TEMPERATURE (°C) 60 80 400 0.9 VOD 300 0.8 200 0.7 100 0.6 0 0.5 0 2 4 6 8 10 12 14 RSET (kΩ) Figure 23. LVDS Output Swing, Common-Mode Voltage vs. RSET, Placed at LVDSBIAS Figure 22. Propagation Delay Adder vs. Temperature Rev. A | Page 14 of 28 04619-039 VDIF (mV) 0.15 VOS (V) 0.20 04619-038 DELAY SENSITIVITY (nS) 1.4 AD9480 EQUIVALENT CIRCUITS AVDD AVDD 16.7kΩ 16.7kΩ 150Ω 150Ω VIN– VIN+ 1.2pF 25kΩ PDWN 1.2pF 30kΩ 04619-007 04619-004 25kΩ Figure 24. Analog Inputs Figure 27. Power-Down Input DRVDD AVDD DRVDD 12kΩ 12kΩ K 1.2V CLK+ CLK– 150Ω 150Ω ILVDSOUT 10kΩ 3.7kΩ 04619-005 10kΩ 04619-008 LVDSBIAS Figure 28. LVDSBIAS Input Figure 25. Clock Inputs DRVDD VDD 30kΩ V+ V– DX– DX+ V– V+ 04619-009 04619-006 S1 Figure 26. S1 Input Figure 29. LVDS Data, DCO Outputs Rev. A | Page 15 of 28 AD9480 APPLICATION NOTES 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 A/D output. Considerable care has been taken in the design of the CLOCK input of the AD9480, and the user is advised to give commensurate thought to the clock source. The AD9480 has an internal clock duty-cycle stabilization circuit that locks to the rising edge of CLOCK and optimizes timing internally for sample rates between 100 MSPS and 250 MSPS. This allows for a wide range of input duty cycles at the input without degrading performance. Jitter on 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 less than 70 MHz nominally. The loop is associated with a time constant that needs to be considered in applications where the clock rate can change dynamically, requiring a wait time of 5 µs after a dynamic clock frequency increase before valid data is available. The clock duty-cycle stabilizer can be disabled at Pin 28 (S1). The clock inputs are internally biased to 1.5 V (nominal) and support either differential or single-ended signals. For best dynamic performance, a differential signal is recommended. An MC100LVEL16 performs well in the circuit to drive the clock inputs (ac coupling is optional). If the clock buffer is greater than 2 inches from the ADC, a standard LVPECL termination may be required instead of the simple pull-down termination, as shown in Figure 30. The analog input to the AD9480 is a differential buffer. For best dynamic performance, impedances at VIN+ and VIN− should match. Optimal performance is obtained when the analog inputs are driven differentially. SNR and SINAD performance can degrade if the analog input is driven with a single-ended signal; however, performance can be adequate for some applications (see Figure 6). The analog inputs self-bias to approximately 1.9 V; this common-mode voltage can be externally overdriven by approximately ±300 mV if required. A wideband transformer, such as the Mini-Circuits® ADT1-1WT, can provide the differential analog inputs for applications that require a single-ended-to-differential conversion. Note that the filter and center-tap capacitor on the secondary side is optional and dependent on application requirements. An RC filter at the secondary side helps reduce any wideband noise aliased by the ADC. (R, C OPTIONAL) VIN+ 49.9Ω 10pF AD9480 33Ω VIN– AGND 0.1µF Figure 31. Driving the ADC with an RF Transformer For dc-coupled applications, the AD8138/AD8139 or AD8351 can serve as a convenient ADC driver, depending on requirements. Figure 32 shows an example with the AD8138. The AD9480 PCB has an optional AD8351 on board, as shown in Figure 41 and Figure 42. The AD8351 typically yields better performance for frequencies greater than 30 MHz to 40 MHz. 49.9Ω 499Ω AD9480 VIN+ AD8138 1.3kΩ CLK+ 20pF 33Ω 523Ω PECL GATE 0.1µF CLK– 2kΩ AVDD 33Ω 499Ω 0.1µF AVDD 33Ω AD9480 VIN– 499Ω 510Ω 04619-010 0.1µF 510Ω Figure 32. Driving the ADC with the AD8138 Figure 30. Clocking the AD9480 Table 8. S1 Voltage Levels S1 Voltage 0.9 × AVDD −> AVDD 2/3 AVDD ± (0.1 × AVDD) 1/3 AVDD ± (0.1 × AVDD) AGND −> (0.1 × AVDD) Data Format Offset binary Offset binary Twos complement Twos complement Rev. A | Page 16 of 28 Duty-Cycle Stabilizer Disabled Enabled Enabled Disabled AGND 04619-012 CLOCKING THE AD9480 ANALOG INPUTS 04619-011 The AD9480 uses a 1.5-bit per stage architecture. The analog inputs drive an integrated high bandwidth track-and-hold circuit that samples the signal prior to quantization by the 8-bit core. For ease of use, the part includes an on-board reference and input logic that accepts TTL, CMOS, or LVPECL levels. The digital output logic levels are LVDS (ANSI 644 compatible). AD9480 The AD9480 can be easily configured for different full-scale ranges. See the Voltage Reference section for more information. Optimal performance is achieved with a 1 V p-p analog input. SENSE = GND VIN+ 500mV 2.0V Fixed Reference The internal reference can be configured for a differential span of 1 V p-p (see Figure 37). It is recommended to place a 0.1 µF capacitor as close as possible to the VREF pin; a 10 µF capacitor is also required (see the PCB layout for guidance). If the internal reference of the AD9480 is used to drive multiple converters to improve gain matching, the loading of the reference by the other converters must be considered. Figure 37 depicts how the internal reference voltage is affected by loading. 2.0V 1.0085 1.0080 VIN– 1.0075 DIGITALOUT = ALL 0s VOLTAGE REFERENCE A stable and accurate 1.0 V reference is built into the AD9480. Users can choose this internal reference or provide an external reference for greater accuracy and flexibility. Figure 35 shows the typical reference variation with temperature. Table 9 summarizes the available reference configurations. 1.0065 1.0060 1.0055 1.0050 1.0045 04619-049 Figure 33. Analog Input Full Scale 1.0070 VREF (V) 04619-013 DIGITALOUT = ALL 1s 1.0040 1.0035 –40 –20 0 20 40 TEMPERATURE (°C) 60 80 Figure 35. Typical Reference Variation with Temperature VIN+ VIN– VREF 10µF 0.1µF ADC CORE 04619-016 SENSE Figure 36. Internal Fixed Reference (1 V p-p) VREF 0.1µF 7kΩ SELECT LOGIC SENSE 0.5V 04619-014 7kΩ –0.1 –0.2 –0.3 –0.4 04619-017 + % CHANGE IN VREF VOLTAGE 10µF 0 Figure 34. Internal Reference Equivalent Circuit –0.5 0 0.5 1.0 1.5 IREF (mA) 2.0 2.5 3.0 Figure 37. Internal VREF vs. Load Current Table 9. Reference Configurations SENSE Voltage AVDD 0.5 V (Self-Biased) AGND to 0.2 V Resulting VREF N/A (External Reference Input) 0.5 × (1 + R1/R2) V 1.0 V Reference External Programmable Internal Fixed Rev. A | Page 17 of 28 Differential Span 1 × External Reference Voltage 1 × VREF (0.75 V p-p to 1.5 V p-p) 1 V p-p AD9480 External Reference An external reference can be used for greater accuracy and temperature stability when required. The gain of the AD9480 can also be varied using this configuration. A voltage output DAC can be used to set VREF, providing for a means to digitally adjust the full-scale voltage. VREF can be externally set to voltages from 0.75 V to 1.5 V; optimum performance is typically obtained at VREF = 1 V. (See the Typical Performance Characteristics section.) MAY REQUIRE RC FILTER EXTERNAL REFERENCE OR DAC INPUT VREF AVDD 04619-018 SENSE Figure 38. External Reference Programmable Reference The programmable reference can be used to set a differential input span anywhere between 0.75 V p-p and 1.5 V p-p by using an external resistor divider. The sense pin will self-bias to 0.5 V, and the resulting VREF is equal to 0.5 × (1 + R1/R2). It is recommended to keep the sum of R1 + R2 ≥ 10 kΩ to limit VREF loading (for VREF = 1.5 V, set R1 equal to 7 kΩ and R2 equal to 3.5 kΩ). VREF 0.1µF R1 SENSE R2 04619-019 10µF trace length 3 inches to 4 inches maximum and the differential output trace lengths as equal as possible. OUTPUT CODING Table 10. Code 255 255 254 • • 129 128 127 • • 2 1 0 0 (VIN+) − (VIN−) >+0.512 V +0.512 V +0.508 V • • +0.004 V +0.0 V –0.004 V • • −0.504 V −0.508 V −0.512 V <−0.512 V Offset Binary 1111 1111 1111 1111 1111 1110 • • 1000 0001 1000 0000 0111 1111 • • 0000 0010 0000 0001 0000 0000 0000 0000 Twos Complement 0111 1111 0111 1111 0111 1110 • • 0000 0001 0000 0000 1111 1111 • • 1000 0010 1000 0001 1000 0000 1000 0000 INTERLEAVING TWO AD9480s Instrumentation applications may prefer to interleave or pingpong two AD9480s to achieve twice the sample rate, or 500 MSPS. In these applications, it is important to match the gain and offset of the two ADCs. Varying the reference voltage allows the gain of the ADCs to be adjusted; external dc offset compensation can be used to reduce offset mismatch between two ADCs. The sampling phase offset between the two ADCs is extremely important as well and requires very low skew between clock signals driving the ADCs (<2 ps clock skew for a 100 MHz analog input frequency). DATA CLOCK OUT Figure 39. Programmable Reference DIGITAL OUTPUTS LVDS outputs are available when a 3.7 kΩ RSET resistor is placed at Pin 42 (LVDSBIAS) to ground. The RSET resistor current (~1.2 V/RSET) is ratioed on-chip, setting the output current at each output equal to a nominal 3.5 mA with an RSET of 3.74 kΩ. Varying the RSET current also linearly changes the LVDS output current, resulting in a variable output swing for a fixed termination resistance. A 100 Ω differential termination resistor placed at the LVDS receiver inputs results in a nominal 350 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 100 Ω termination resistor as close to the receiver as possible. Keep the An LVDS data clock is available at DCO+ and DCO−. These clocks can facilitate latching off-chip, providing a low skew clocking solution. The on-chip delay of the DCO clocks tracks with the on-chip delay of the data bits (under similar loading), such that the variation between TPD and TCPD is minimized. It is recommended to keep the trace lengths on the data and DCO pins matched and to 3 inches to 4 inches maximum. The output and DCO outputs should be designed for a differential characteristic impedance of 100 Ω and terminated differentially at the receiver with 100 Ω. POWER-DOWN The chip can be placed in a low power state by driving the PDWN pin to logic high. Typical power-down dissipation is 15 mW. The data outputs and DCO outputs are high impedance in power-down state. The time it takes to go into power-down from assertion of PDWN is one cycle; recovery from powerdown is accomplished in three cycles. Rev. A | Page 18 of 28 AD9480 AD9480 EVALUATION BOARD The AD9480 evaluation board offers an easy way to test the device. It requires a clock source, an analog input signal, and a 3.3 V power supply. The clock source is buffered on the board to provide the clocks for the ADC and a data-ready signal. The digital outputs and output clocks are available at a 40-pin connector, P10. The board has several modes of operation and is shipped in the following configuration: • Offset binary • Internal voltage reference POWER CONNECTOR Table 11. Power Connector 2 The clock input is terminated to ground through 50 Ω at SMA Connector J1. The input is ac-coupled to a high speed differential receiver (LVEL16) that provides the required low jitter and fast edge rates needed for best performance. J1 input should be >0.5 V p-p. Power to the LVEL16 is set to VCTRL (default) or AVDD by jumper placement at the device. Comments Analog supply for ADC ~ 150 mA Output supply for ADC ~ 40 mA Supply for support clock circuitry ~ 50 mA Optional supply for op amp and ADR510 reference AVDD, DRVDD, and VCTRL are the minimum required power connections. LVEL16 clock buffer can be powered from AVDD or VCTRL LVEL16 buffer jumper. ANALOG INPUTS The evaluation board accepts a 700 mV p-p analog input signal centered at ground at SMB Connector J3. This signal is terminated to ground through 50 Ω by R22. The input can be alternatively terminated at the T1 transformer secondary by R21 and R28. T1 is a wideband RF transformer that provides the single-ended-to-differential conversion, allows the ADC to be driven differentially, and minimizes even-order harmonics. An optional transformer, T4, can be placed, if desired (remove T1, as shown in Figure 41 and Figure 42). The PCB has been designed to accommodate the SNLVDS1 line driver. The SNLVDS1 is used as a high speed LVDS-level optional encode clock. To use this clock, remove C2, C5, and C6. Place a 0.1 µF capacitor on C34, C35, and C26. Place a 10 Ω resistor on R48, a 100 Ω resistor on R6, and a 0 Ω resistor on R49 and R53. For best results using the LVDS line driver, J1 input should be >2.5 V p-p. OPTIONAL XTAL The PCB has been designed to accommodate an optional crystal oscillator that can serve as a convenient clock source. The footprint can accept both through-hole and surface-mount devices, including Vectron XO-400 and Vectron VCC6 family oscillators. OUT+ VCC The analog signal can be low-pass filtered by R31, C8, and R29, C9 at the ADC input. OUT– GAIN GND Full scale is set by the sense jumper. This jumper applies a bias to the SENSE pin to vary the full-scale range; the default position is SENSE = ground, setting the full scale to 1 V p-p. VCC 04619-040 1 CLOCK OPTIONAL CLOCK BUFFER Power is supplied to the board via two detachable 4-pin power strips. Terminal AVDD1 3.3 V DRVDD1 3.3 V VCTRL1, 2 3.3 V Op Amp, External Reference with a 1.2 kΩ resistor and R42 with a 100 Ω resistor. Populate R52 with a 10 kΩ resistor. Figure 40. XTAL Footprint OPTIONAL OPERATIONAL AMPLIFIER The PCB has been designed to accommodate an optional AD8351 op amp, which can serve as a convenient solution for dc-coupled applications. To use the AD8351 op amp, remove R29, R31, and C3. Populate R40, R43, and R47 with 25 Ω resistors, and populate C24, C28, C29, C30, C31, and C32 with 0.1 µF capacitors. Populate R38, R39, and R51 with a 10 Ω resistor, and R44 and R45 with a 1 kΩ resistor. Populate R41 To use either crystal, populate C26 and C27 with 0.1 µF capacitors. Populate R49 and R53 with 0 Ω resistors. Place 1 kΩ resistors on R54, R55, R56, and R57 and remove C6 and C5. If the Vectron VCC6 family crystal is being used, populate R48 with a 10 Ω resistor. If using the XO-400 crystal, place Jumper E21 or Jumper E22 to Jumper E23. Rev. A | Page 19 of 28 AD9480 VOLTAGE REFERENCE DATA OUTPUTS The AD9480 has an internal 1 V reference mode. The ADC uses the internal 1 V reference as the default when SENSE is set to ground. An optional on-board external 1.0 V reference (ADR510) can be used by setting the SENSE jumper to AVDD, by placing a jumper on E20 to E3, and by placing a 0 Ω resistor on R36. When using an external programmable reference (R20, R30), the SENSE jumper must be removed. The off-chip drivers provide LVDS-compatible output levels with an LVDS RSET resistor of 3.74 kΩ. The ADC digital outputs can be terminated on the board by 100 Ω resistors at the connector if receiving logic does not have the required termination resistance. (The on-chip LVDS output drivers require a far-end, 100 Ω differential termination.) Rev. A | Page 20 of 28 AD9480 EVALUATION BOARD BILL OF MATERIALS (BOM) Table 12. No. 1 Quantity 23 2 3 4 5 6 7 8 1 4 2 2 2 2 10 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 6 1 3 3 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 7 29 12 30 18 31 1 Reference Designator C1 to C6, C10 to C12, C17 to C23, C26 to C28, C31 to C33, C35 C13 C7, C14 to C16 J1, J3 P12, P13 P12, P13 R22, R27 R2 to R5, R7 to R10, R15, R42 (All not placed) R1, R44, R45, R50, R58, R59 R41 R40, R43, R47 R38, R39, R51 R25, R26 R23, R24 R32, R34 R29, R31 R33, R52 R63 T1 U13 U2 U14 U15 U1 U12 U11 T2 C8, C9, C24, C25, C29, C30, and C34 (All not placed) R6, R20, R21, R28, R30, R36, R46, R48, R49, and R55 to R57 (All not placed) E5 to E8, E17, E35, E73 to E84 P10 Device Capacitors Package 0402 Value 0.1 µF Capacitor Capacitors SMAs 4-pin power connector posts 4-pin power detachable connectors Resistors Resistors Tantalum (3528) Tantalum (6032) 10 µF 10 µF Z5.531.3425.0 25.602.5453.0 0603 0603 Wieland Wieland 50 Ω 100 Ω Resistors Resistors Resistors Resistors Resistors Resistors Resistors Resistors Resistors Resistor Transformer AD8351 SN65LVDS1 ADR510 VCC6PECL6 XO-400 AD9480 MC100LVEL16D ETC1-1-13 Capacitors 0603 0603 0603 0603 0603 0603 0603 0603 0603 0603 CD542 MSOP-10 SN65LVDS1 DBV SOT-23 VCC6-QAB-250M000 Dip4(14) TQFP-44 S08NB 1-1 TX 0402 1000 Ω 1200 Ω 25 Ω 10 Ω 82 Ω 510 Ω 130 Ω 0Ω 10 kΩ 3.74 kΩ Mini-Circuits T1-1WT Not placed Not placed Resistors 0603 User-determined 40-pin right angle Digi-Key S2131-20-ND Not placed Not placed Not placed Not placed Jumpers Output Data Connector Rev. A | Page 21 of 28 CM Rev. A | Page 22 of 28 Figure 41. PCB Schematic (1 of 2) GND VCTRL AVDD R27 R23 50Ω 510Ω C11 0.1µF CLKINPUT GND 4 5 6 C10 0.1µF CM 3 4 E8 2 5 AMPIN GND J1 CLK ANALOG INPUT R22 50 J3 GND GND 1 6 3 3 2 8 C11 0.1µF R21 X C4 0.1µF GND 5 6 U11 CLKN Q VBB VEE 100LVEL16 R VCC 7 CLK Q 1 R24 4 510Ω E11 E10 T1+ R28 X GND GND R63 GND 3.7kΩ AVDD GND GND AVDD GND GND R25 130Ω R32 82Ω C5 0.1µF C6 0.1µF E17 E17 44 43 42 41 40 39 38 37 36 35 34 R6 X GND AVDD GND PWDN S1 33 32 31 30 29 28 27 26 25 24 23 VREF AGND AVDD AGND VIN– VIN+ AGND AVDD LVDSBIAS NC AGND 1 CLK+ U12 FOR OP AMP CONFIGURATION REMOVE RESISTORS R29, R31, AND C3 C9 X C12 0.1µF GND R34 82Ω VCTRL GND R26 130Ω E7 AMPOUT GND E17 R30 XX R20 XX C13 + 10µF VCTRL GND R29 00 GND R31 00 C8 X C10 0.1µF AMPOUT GND T1– 2 CM 1 E9 T1– CM T1+ E1 E16 FOR ON BOARD EXT. REF JUMPER E13 TO 14 AND E20 TO E3 PLACE R36 0Ω AND R33 10kΩ AD9480 D4C DRVDD DCO+ DCO– DRGND D3T D3C D2T P7 E35 P6 2 3 4 5 6 CLK– C33 0.1µF 7 8 GND DRVDD GND CLKN CLK P16 P14 D– D+ AVDD AVDD GND VCTRL P17 P15 PADS FOR SHORTING EL16, 9 10 11 12 13 14 15 16 17 19 18 D5T 22 21 D5C D4T 20 GND VAMP GND DRVDD GND AVDD GND TIN1 VCTRL R36 1kΩ OPTIONAL E2 E15 GND VCTRL 04619-041 GND C1 0.1µF GND VCTRL E14 4 R36 X E13 3 3 U14 ADR510 TRIM/NC 2 GND V+ V– 1 OPTIONAL TRANSFORMER E3 1 2 4 E20 R33 10kΩ 3 VAMP EXTVREF GND POWER CONN. 2 CLK+ CLK– AVDD AGND DRVDD DRGND D0C D0T D1C D1T D2C 1 AVDD GND DRVDD GND P1 P2 P3 P4 P1 P2 P3 P4 SENSE AGND AVDD AGND PWDN S1 DRGND D7T D7C D6T D6C P13 P12 PTMICRO4 PTMICRO4 D0C D0T D1C D1T D2C D2T D3C D3T DR– DR+ D4C D4T D5C D5T D6C D6T D7C D7T E4 E70 E12 E32 GND GND GND GND GND GND GND GND E77 E78 E79 E81 E80 E82 E83 E84 PROBE POINTS R8 100Ω R9 100Ω R10 100Ω R7 100Ω R15 100Ω R5 100Ω R4 100Ω R3 100Ω R2 100Ω GND GND DR+ GND D7C D6C D5C D4C D3C D2C D1C D0C 4 2 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 P40 P38 P36 P34 P32 P30 P28 P26 P24 P22 P20 P18 P16 P14 P12 P10 P8 P6 P4 P2 C40MS P10 P39 P37 P35 P33 P31 P29 P27 P25 P23 P21 P19 P17 P15 P13 P11 P9 P7 P5 P3 P1 1 3 5 7 9 11 13 15 17 19 21 23 25 29 27 31 33 35 37 39 OUTPUT DATA CONN. GND GND DR– GND D7T D6T D5T D4T D3T D2T D1T D0T AD9480 PCB SCHEMATICS Figure 42. PCB Schematic (2 of 2) Rev. A | Page 23 of 28 04619-042 E25 C31 X C30 X R42 X R51 X R39 X R52 X VAMPF E31 E29 E34 E28 OUT+ 4 3 R41 X U13 AD8351 OPTIONAL RPG2 5 INLO INHI GND AVDD S1 PWUP 1 RGP1 2 X C34 PWDN CLKINPUT GND R40 X AMPIN GND E30 E27 R58 1kΩ R50 1kΩ E36 E26 E24 R59 1kΩ VCTRL VCTRL 3 2 1 U2 Y D VPOS OPHI 6 COMM OPLO VOCM 9 8 VAMPF 10 7 4 5 OUT+ VIVIS GND C16 + 10µF P4 P3VAMP GND VAMPF R44 X R45 X C28 0.1µF C29 X R46 X C24 X GND GND AMPOUT C25 X AMPOUT X R38 X= NOT NORMALLY POPULATED XX = USER SELECTED, IS NOT NORMALLY POPULATED SN65LVDS1 OPTIONAL Z GND VCC C32 0.1µF VCTRL AVDD VAMPF VCTRL E21 E23 E22 R48 X C23 X GND C27 X GND GND C14 + 10µF DRVDD GND C7 + 10µF AVDD GND 1 2 3 GND C21 0.1µF C17 0.1µF OUT VEE –OUT VCC U1 XO-400 VCC 6 PECL6 7 14 GND OUT+ 6 OUT– 5 4 1 8 VCTRL R54 X R55 X VCTRL C20 0.1µF C15 + 10µF VCTRL C19 0.1µF OPTIONAL XTALS C22 0.1µF C18 0.1µF GND R57 X R56X GND C23 0.1µF C35 0.1µF R53 X R49 X CLK– CLK+ AD9480 AD9480 04619-043 04619-045 PCB LAYERS 04619-044 04619-046 Figure 45. PCB Ground Layer Figure 43. PCB Top-Side Silkscreen Figure 46. PCB Split Power Plane Figure 44. PCB Top-Side Copper Routing Rev. A | Page 24 of 28 04619-047 04619-048 AD9480 Figure 48. PCB Bottom-Side Silkscreen Figure 47. PCB Bottom-Side Copper Routing Rev. A | Page 25 of 28 AD9480 OUTLINE DIMENSIONS 1.20 MAX 0.75 0.60 0.45 12.00 BSC SQ 34 44 1 33 PIN 1 TOP VIEW 10.00 BSC SQ (PINS DOWN) 0° MIN 1.05 1.00 0.95 0.15 0.05 0.20 0.09 7° 3.5° 0° 0.08 MAX COPLANARITY SEATING PLANE 23 11 12 VIEW A VIEW A 22 0.80 BSC LEAD PITCH ROTATED 90° CCW 0.45 0.37 0.30 COMPLIANT TO JEDEC STANDARDS MS-026ACB Figure 49. 44-Lead Thin Plastic Quad Flat Package [TQFP] (SU-44) Dimensions shown in millimeters ORDERING GUIDE Model AD9480BSUZ-2501, 2 AD9480ASUZ-2501 AD9480-LVDS/PCB3 Temperature Range −40°C to +85°C −40°C to +85°C Description 44-Lead Thin Plastic Quad Flat Package (TQFP) 44-Lead Thin Plastic Quad Flat Package (TQFP) Evaluation Board 1 Z = Pb-free part. Optimized differential nonlinearity. 3 Evaluation board shipped with AD9480BSUZ-250 installed. 2 Rev. A | Page 26 of 28 Package Option SU-44 SU-44 AD9480 NOTES Rev. A | Page 27 of 28 AD9480 NOTES ©2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04619–0–4/05(A) Rev. A | Page 28 of 28