Data Sheet 1.6 GHz Clock Distribution IC, Dividers, Delay Adjust, Two Outputs AD9515 FEATURES 1.6 GHz differential clock input 2 programmable dividers Divide-by in range from1 to 32 Phase select for coarse delay adjust 1.6 GHz LVPECL clock output Additive output jitter 225 fs rms 800 MHz/250 MHz LVDS/CMOS clock output Additive output jitter 300 fs rms/290 fs rms Time delays up to 10 ns Device configured with 4-level logic pins Space-saving, 32-lead LFCSP FUNCTIONAL BLOCK DIAGRAM RSET VS GND AD9515 LVPECL OUT0 /1. . . /32 OUT0B CLK CLKB LVDS/CMOS OUT1 ∆t /1. . . /32 OUT1B SYNCB APPLICATIONS Low jitter, low phase noise clock distribution Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs High performance wireless transceivers High performance instrumentation Broadband infrastructure ATE VREF S10 S9 S8 S7 S6 S5 S4 S3 S2 S1 S0 05597-001 SETUP LOGIC Figure 1. GENERAL DESCRIPTION The AD9515 features a two-output clock distribution IC in a design that emphasizes low jitter and phase noise to maximize data converter performance. Other applications with demanding phase noise and jitter requirements also benefit from this part. There are two independent clock outputs. One output is LVPECL, while the other output can be set to either LVDS or CMOS levels. The LVPECL output operates to 1.6 GHz. The other output operates to 800 MHz in LVDS mode and to 250 MHz in CMOS mode. Each output has a programmable divider that can be set to divide by a selected set of integers ranging from 1 to 32. The phase of one clock output relative to the other clock output can be set by means of a divider phase select function that serves as a coarse timing adjustment. The LVDS/CMOS output features a delay element with three selectable full-scale delay values (1.5 ns, 5 ns, and 10 ns), each with 16 steps of fine adjustment. The AD9515 does not require an external controller for operation or setup. The device is programmed by means of 11 pins (S0 to S10) using 4-level logic. The programming pins are internally biased to ⅓ VS. The VREF pin provides a level of ⅔ VS. VS (3.3 V) and GND (0 V) provide the other two logic levels. The AD9515 is ideally suited for data converter clocking applications where maximum converter performance is achieved by encode signals with subpicosecond jitter. The AD9515 is available in a 32-lead LFCSP and operates from a single 3.3 V supply. The temperature range is −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 © 2005–2012 Analog Devices, Inc. All rights reserved. AD9515 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Synchronization .......................................................................... 18 Applications ....................................................................................... 1 RSET Resistor ................................................................................ 19 Functional Block Diagram .............................................................. 1 VREF ............................................................................................ 19 General Description ......................................................................... 1 Setup Configuration................................................................... 19 Revision History ............................................................................... 2 Programming .................................................................................. 20 Specifications..................................................................................... 3 Divider Phase Offset .................................................................. 22 Clock Input .................................................................................... 3 Delay Block ................................................................................. 22 Clock Outputs ............................................................................... 3 Outputs ........................................................................................ 23 Timing Characteristics ................................................................ 4 Power Supply............................................................................... 23 Clock Output Phase Noise .......................................................... 5 Power Management ................................................................... 24 Clock Output Additive Time Jitter ............................................. 8 Applications..................................................................................... 25 SYNCB, VREF, and Setup Pins ................................................... 9 Using the AD9515 Outputs for ADC Clock Applications .... 25 Power ............................................................................................ 10 LVPECL Clock Distribution ..................................................... 25 Timing Diagrams ............................................................................ 11 LVDS Clock Distribution .......................................................... 26 Absolute Maximum Ratings.......................................................... 12 CMOS Clock Distribution ........................................................ 26 Thermal Characteristics ............................................................ 12 Setup Pins (S0 to S10) ................................................................ 26 ESD Caution ................................................................................ 12 Power and Grounding Considerations and Power Supply Rejection ...................................................................................... 26 Pin Configuration and Function Descriptions ........................... 13 Terminology .................................................................................... 14 Typical Performance Characteristics ........................................... 15 Functional Description .................................................................. 18 Phase Noise and Jitter Measurement Setups........................... 27 Outline Dimensions ....................................................................... 28 Ordering Guide .......................................................................... 28 Overall.......................................................................................... 18 CLK, CLKB—Differential Clock Input ................................... 18 REVISION HISTORY 4/12—Rev. 0 to Rev. A Changes to Table 9 .......................................................................... 13 Updated Outline Dimensions ....................................................... 28 Changes to Ordering Guide .......................................................... 28 7/05—Revision 0: Initial Version Rev. A | Page 2 of 28 Data Sheet AD9515 SPECIFICATIONS Typical (typ) is given for VS = 3.3 V ± 5%, TA = 25°C, RSET = 4.12 kΩ, LVPECL swing = 790 mV, unless otherwise noted. Minimum (min) and maximum (max) values are given over full VS and TA (−40°C to +85°C) variation. CLOCK INPUT Table 1. Parameter CLOCK INPUT (CLK) Input Frequency 1 Input Sensitivity1 Input Common-Mode Voltage, VCM Input Common-Mode Range, VCMR Input Sensitivity, Single-Ended Input Resistance Input Capacitance Min Typ 0 1.5 1.3 4.0 150 1.6 150 4.8 2 Max Unit 1.6 GHz mV p-p V V mV p-p kΩ pF 1.7 1.8 5.6 Test Conditions/Comments Self-biased; enables ac coupling With 200 mV p-p signal applied; dc-coupled CLK ac-coupled; CLKB ac-bypassed to RF ground Self-biased 1 A slew rate of 1 V/ns is required to meet jitter, phase noise, and propagation delay specifications. CLOCK OUTPUTS Table 2. Parameter LVPECL CLOCK OUTPUT (OUT0) Differential Output Frequency Output High Voltage (VOH) Output Low Voltage (VOL) Output Differential Voltage (VOD) LVDS CLOCK OUTPUT (OUT1) Differential Output Frequency Differential Output Voltage (VOD) Delta VOD Output Offset Voltage (VOS) Delta VOS Short-Circuit Current (ISA, ISB) CMOS CLOCK OUTPUT (OUT1) Single-Ended Output Frequency Output Voltage High (VOH) Output Voltage Low (VOL) Min Typ Max Unit 0 VS − 1.1 VS − 1.90 640 VS − 0.96 VS − 1.76 790 1.6 VS − 0.82 VS − 1.52 960 GHz V V mV Test Conditions/Comments Termination = 50 Ω to VS − 2 V Termination = 100 Ω differential 0 250 350 1.125 1.23 14 0 VS − 0.1 800 450 30 1.375 25 24 MHz mV mV V mV mA 250 MHz V V 0.1 Rev. A | Page 3 of 28 Output shorted to GND Single-ended measurements; termination open Complementary output on (OUT1B) With 5 pF load @ 1 mA load @ 1 mA load AD9515 Data Sheet TIMING CHARACTERISTICS CLK input slew rate = 1 V/ns or greater. Table 3. Parameter LVPECL Output Rise Time, tRP Output Fall Time, tFP PROPAGATION DELAY, tPECL, CLK-TO-LVPECL OUT Divide = 1 Divide = 2 − 32 Variation with Temperature OUTPUT SKEW, LVPECL OUTPUT LVPECL OUT Across Multiple Parts, tSKP_AB3 1 LVDS Output Rise Time, tRL Output Fall Time, tFL PROPAGATION DELAY, tLVDS, CLK-TO-LVDS OUT OUT3 to OUT4 Divide = 1 Divide = 2 − 32 Variation with Temperature OUTPUT SKEW, LVDS OUTPUT LVDS OUT Across Multiple Parts, tSKV_AB1 CMOS Output Rise Time, tRC Output Fall Time, tFC PROPAGATION DELAY, tCMOS, CLK-TO-CMOS OUT Divide = 1 Divide = 2 − 32 Variation with Temperature OUTPUT SKEW, CMOS OUTPUT CMOS OUT Across Multiple Parts, tSKC_AB1 LVPECL-TO-LVDS OUT Output Delay, tSKP_V LVPECL-TO-CMOS OUT Output Delay, tSKP_C DELAY ADJUST (OUT2; LVDS AND CMOS) S0 = 1/3 Zero Scale Delay Time 2 Zero Scale Variation with Temperature Full Scale Time Delay2 Full Scale Variation with Temperature S0 = 2/3 Zero Scale Delay Time2 Zero Scale Variation with Temperature Full Scale Time Delay2 Full Scale Variation with Temperature Min 355 395 1.00 1.05 Typ Max Unit 60 60 100 100 ps ps 480 530 0.5 635 710 ps ps ps/°C 125 ps 200 210 350 350 ps ps 1.25 1.30 0.9 1.55 1.60 ns ns ps/°C 230 ps 650 650 865 990 ps ps 1.45 1.50 1 1.75 1.80 ns ns ps/°C 300 ps Test Conditions/Comments Termination = 50 Ω to VS − 2 V 20% to 80%, measured differentially 80% to 20%, measured differentially Termination = 100 Ω differential 20% to 80%, measured differentially 80% to 20%, measured differentially Delay off on OUT4 Delay off on OUT4 1.10 1.15 B outputs are inverted; termination = open 20% to 80%; CLOAD = 3 pF 80% to 20%; CLOAD = 3 pF Delay off on OUT4 Delay off on OUT4 700 970 1150 ps 0.88 1.14 1.43 ns 0.34 0.20 1.7 −0.38 ns ps/°C ns ps/°C 0.45 0.31 5.9 −1.3 ns ps/°C ns ps/°C Rev. A | Page 4 of 28 Everything the same; different logic type LVPECL to LVDS on same part Everything the same; different logic type LVPECL to CMOS on same part Data Sheet Parameter S0 = 1 Zero Scale Delay Time2 Zero Scale Variation with Temperature Full Scale Time Delay2 Full Scale Variation with Temperature Linearity, DNL Linearity, INL 1 2 AD9515 Min Typ Max 0.56 0.47 11.4 −5 0.2 0.2 Unit Test Conditions/Comments ns ps/°C ns ps/°C LSB LSB This is the difference between any two similar delay paths across multiple devices operating at the same voltage and temperature. Incremental delay; does not include propagation delay. CLOCK OUTPUT PHASE NOISE CLK input slew rate = 1 V/ns or greater. Table 4. Parameter CLK-TO-LVPECL ADDITIVE PHASE NOISE CLK = 622.08 MHz, OUT = 622.08 MHz Divide = 1 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset >1 MHz Offset CLK = 622.08 MHz, OUT = 155.52 MHz Divide = 4 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset >1 MHz Offset CLK = 622.08 MHz, OUT = 38.88 MHz Divide = 16 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset >1 MHz Offset CLK = 491.52 MHz, OUT = 61.44 MHz Divide = 8 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset > 1 MHz Offset Min Typ Max Unit −125 −132 −140 −148 −153 −154 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −128 −140 −148 −155 −161 −161 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −135 −145 −158 −165 −165 −166 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −131 −142 −153 −160 −165 −165 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz Rev. A | Page 5 of 28 Test Conditions/Comments AD9515 Parameter CLK = 491.52 MHz, OUT = 245.76 MHz Divide = 2 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset >1 MHz Offset CLK = 245.76 MHz, OUT = 61.44 MHz Divide = 4 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset >1 MHz Offset CLK-TO-LVDS ADDITIVE PHASE NOISE CLK = 622.08 MHz, OUT= 622.08 MHz Divide = 1 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset CLK = 622.08 MHz, OUT = 155.52 MHz Divide = 4 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset CLK = 491.52 MHz, OUT = 245.76 MHz Divide = 2 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset Data Sheet Min Typ Max Unit −125 −132 −140 −151 −157 −158 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −138 −144 −154 −163 −164 −165 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −100 −110 −118 −129 −135 −140 −148 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −112 −122 −132 −142 −148 −152 −155 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −108 −118 −128 −138 −145 −148 −154 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz Rev. A | Page 6 of 28 Test Conditions/Comments Data Sheet Parameter CLK = 491.52 MHz, OUT = 122.88 MHz Divide = 4 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset CLK = 245.76 MHz, OUT = 245.76 MHz Divide = 1 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset CLK = 245.76 MHz, OUT = 122.88 MHz Divide = 2 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset CLK-TO-CMOS ADDITIVE PHASE NOISE CLK = 245.76 MHz, OUT = 245.76 MHz Divide = 1 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset CLK = 245.76 MHz, OUT = 61.44 MHz Divide = 4 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset AD9515 Min Typ Max Unit −118 −129 −136 −147 −153 −156 −158 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −108 −118 −128 −138 −145 −148 −155 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −118 −127 −137 −147 −154 −156 −158 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −110 −121 −130 −140 −145 −149 −156 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −125 −132 −143 −152 −158 −160 −162 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz Rev. A | Page 7 of 28 Test Conditions/Comments AD9515 Data Sheet Parameter CLK = 78.6432 MHz, OUT = 78.6432 MHz Divide = 1 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset @ 1 MHz Offset >10 MHz Offset CLK = 78.6432 MHz, OUT = 39.3216 MHz Divide = 2 @ 10 Hz Offset @ 100 Hz Offset @ 1 kHz Offset @ 10 kHz Offset @ 100 kHz Offset >1 MHz Offset Min Typ Max Unit −122 −132 −140 −150 −155 −158 −160 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz −128 −136 −146 −155 −161 −162 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz Test Conditions/Comments CLOCK OUTPUT ADDITIVE TIME JITTER Table 5. Parameter LVPECL OUTPUT ADDITIVE TIME JITTER CLK = 622.08 MHz LVPECL (OUT0) = 622.08 MHz Divide = 1 CLK = 622.08 MHz LVPECL (OUT0) = 155.52 MHz Divide = 4 CLK = 400 MHz LVPECL (OUT0) = 100 MHz Divide = 4 CLK = 400 MHz LVPECL (OUT0) = 100 MHz Divide = 4 LVDS (OUT1) = 100 MHz CLK = 400 MHz LVPECL (OUT0) = 100 MHz Divide = 4 LVDS (OUT1) = 50 MHz CLK = 400 MHz LVPECL (OUT0) = 100 MHz Divide = 4 CMOS (OUT1) = 50 MHz LVDS OUTPUT ADDITIVE TIME JITTER CLK = 400 MHz LVDS (OUT1) = 100 MHz Divide = 4 CLK = 400 MHz LVDS (OUT1) = 100 MHz Divide = 4 LVPECL (OUT0)= 50 MHz Min Typ Max Unit Test Conditions/Comments 40 fs rms BW = 12 kHz − 20 MHz (OC-12) OUT1 off 55 fs rms BW = 12 kHz − 20 MHz (OC-3) OUT1 off 215 fs rms Calculated from SNR of ADC method OUT1 off 215 fs rms Calculated from SNR of ADC method 225 fs rms Interferer Calculated from SNR of ADC method 230 fs rms Interferer Calculated from SNR of ADC method 300 fs rms 350 fs rms Interferer Delay off Calculated from SNR of ADC method OUT0 off Calculated from SNR of ADC method OUT0 off Interferer Rev. A | Page 8 of 28 Data Sheet AD9515 Parameter CMOS OUTPUT ADDITIVE TIME JITTER CLK = 400 MHz CMOS (OUT1) = 100 MHz Divide = 4 Min CLK = 400 MHz CMOS (OUT1) = 100 MHz Divide = 4 LVPECL (OUT0) = 50 MHz DELAY BLOCK ADDITIVE TIME JITTER 1 Delay FS = 1.5 ns Fine Adj. 00000 Delay FS = 1.5 ns Fine Adj. 11111 Delay FS = 5 ns Fine Adj. 00000 Delay FS = 5 ns Fine Adj. 11111 Delay FS = 10 ns Fine Adj. 00000 Delay FS = 10 ns Fine Adj. 11111 1 Typ Max Unit 290 fs rms Test Conditions/Comments Delay off Calculated from SNR of ADC method 315 fs rms Calculated from SNR of ADC method Interferer 100 MHz output; incremental additive jitter1 0.71 1.2 1.3 2.7 2.0 2.8 ps rms ps rms ps rms ps rms ps rms ps rms This value is incremental. That is, it is in addition to the jitter of the LVDS or CMOS output without the delay. To estimate the total jitter, the LVDS or CMOS output jitter should be added to this value using the root sum of the squares (RSS) method. SYNCB, VREF, AND SETUP PINS Table 6. Parameter SYNCB Logic High Logic Low Capacitance VREF Output Voltage S0 TO S10 Levels 0 1/3 2/3 1 Min Typ Max Unit 0.40 V V pF 0.76 VS V 0.1 VS 0.45 VS 0.8 VS V V V V 2.7 2 0.62 VS 0.2 VS 0.55 VS 0.9 VS Test Conditions/Comments Minimum − maximum from 0 mA to 1 mA load Rev. A | Page 9 of 28 AD9515 Data Sheet POWER Table 7. Parameter POWER-ON SYNCHRONIZATION 1 VS Transit Time from 2.2 V to 3.1 V POWER DISSIPATION POWER DELTA Divider (Divide = 2 to Divide = 1) LVPECL Output LVDS Output CMOS Output (Static) CMOS Output (@ 62.5 MHz) CMOS Output (@ 125 MHz) Delay Block 1 Min Typ Max 35 Unit ms Test Conditions/Comments See the Power-On SYNC section. 215 285 380 mW 300 370 465 mW 330 405 510 mW Both outputs on. LVPECL (divide = 2), LVDS (divide = 2). No clock. Does not include power dissipated in external resistors. Both outputs on. LVPECL (divide = 2), CMOS (divide = 2); at 62.5 MHz out (5 pF load). Both outputs on. LVPECL, CMOS (divide = 2); at 125 MHz out (5 pF load). 15 65 20 30 80 110 30 30 90 50 40 110 150 45 45 125 85 50 140 190 65 mW mW mW mW mW mW mW For each divider. No clock. For each output. No clock. No clock. No clock. Single-ended. At 62.5 MHz out with 5 pF load. Single-ended. At 125 MHz out with 5 pF load. Off to 1.5 ns fs, delay word = 60; output clocking at 62.5 MHz. This is the rise time of the VS supply that is required to ensure that a synchronization of the outputs occurs on power-up. The critical factor is the time it takes the VS to transition the range from 2.2 V to 3 .1 V. If the rise time is too slow, the outputs will not be synchronized. Rev. A | Page 10 of 28 Data Sheet AD9515 TIMING DIAGRAMS tCLK CLK DIFFERENTIAL 80% tPECL LVDS 05597-002 tCMOS tRL tFL 05597-065 20% tLVDS Figure 4. LVDS Timing, Differential Figure 2. CLK/CLKB to Clock Output Timing, Divide = 1 Mode SINGLE-ENDED DIFFERENTIAL 80% 80% CMOS 3pF LOAD LVPECL tFP 05597-064 tRP tRC tFC Figure 5. CMOS Timing, Single-Ended, 3 pF Load Figure 3. LVPECL Timing, Differential Rev. A | Page 11 of 28 05597-066 20% 20% AD9515 Data Sheet ABSOLUTE MAXIMUM RATINGS Table 8. Parameter or Pin VS RSET CLK, CLKB CLK OUT0, OUT0B, OUT1, OUT1B Junction Temperature 1 Storage Temperature Lead Temperature (10 sec) With Respect to GND GND GND CLKB GND Min −0.3 −0.3 −0.3 −1.2 −0.3 −65 Max +3.6 VS + 0.3 VS + 0.3 +1.2 VS + 0.3 150 +150 300 Unit V V V V V °C °C °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 ratings for extended periods may affect device reliability. THERMAL CHARACTERISTICS 2 Thermal Resistance 32-Lead LFCSP 3 θJA = 36.6°C/W 1 See Thermal Characteristics for θJA. Thermal impedance measurements were taken on a 4-layer board in still air in accordance with EIA/JESD51-7. 3 The external pad of this package must be soldered to adequate copper land on board. 2 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 12 of 28 Data Sheet AD9515 25 S0 26 VS 28 DNC 27 DNC 30 VS 29 VS 32 RSET 31 GND PIN CONFIGURATION AND FUNCTION DESCRIPTIONS VS 1 THE EXPOSED PADDLE IS AN ELECTRICAL AND THERMAL CONNECTION 24 VS CLK 2 23 OUT0 CLKB 3 VS 4 1 21 VS TOP VIEW (Not to Scale) SYNCB 5 32 25 24 22 OUT0B AD9515 20 VS VREF 6 EXPOSED PAD (BOTTOM VIEW) GND 19 OUT1 S10 7 18 OUT1B S9 8 9 8 05597-006 17 16 05597-005 S1 16 S2 15 S4 13 S3 14 S5 12 S6 11 S7 10 S8 9 17 VS Figure 7. Exposed Paddle Figure 6. 32-Lead LFCSP Pin Configuration Note that the exposed paddle on this package is an electrical connection as well as a thermal enhancement. For the device to function properly, the paddle must be soldered to a PCB land that functions as both a heat dissipation path as well as an electrical ground (analog). Table 9. Pin Function Descriptions Pin No. 1, 4, 17, 20, 21, 24, 26, 29, 30 2 3 5 6 25, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7 18 19 22 23 27, 28 31, Exposed Paddle 32 Mnemonic VS CLK CLKB SYNCB VREF S0 to S10 Description Power Supply (3.3 V). Clock Input. Complementary Clock Input. Used in conjunction with CLK. Used to Synchronize the Outputs; Active Low Signal. Provides 2/3 VS Reference Voltage for Use with Programming Pins S0 to S10. Programming Pins. These pins determine the operation of the AD9515; 4-state logic. OUT1B OUT1 OUT0B OUT0 DNC GND RSET Complementary LVDS/Inverted CMOS Output. Includes a delay block. LVDS/CMOS Output. Includes a delay block. Complementary LVPECL Output. LVPECL Output. Do Not Connect. Ground. The exposed paddle on the back of the chip is also GND. Current Sets Resistor to Ground. Nominal value = 4.12 kΩ. Rev. A | Page 13 of 28 AD9515 Data Sheet TERMINOLOGY Phase Jitter and Phase Noise An ideal sine wave can be thought of as having a continuous and even progression of phase with time from 0 to 360 degrees for each cycle. Actual signals, however, display a certain amount of variation from ideal phase progression over time. This phenomenon is called phase jitter. Although there are many causes that can contribute to phase jitter, one major component is due to random noise that is characterized statistically as being Gaussian (normal) in distribution. This phase jitter leads to a spreading out of the energy of the sine wave in the frequency domain, producing a continuous power spectrum. This power spectrum is usually reported as a series of values whose units are dBc/Hz at a given offset in frequency from the sine wave (carrier). The value is a ratio (expressed in dB) of the power contained within a 1 Hz bandwidth with respect to the power at the carrier frequency. For each measurement, the offset from the carrier frequency is also given. It is also meaningful to integrate the total power contained within some interval of offset frequencies (for example, 10 kHz to 10 MHz). This is called the integrated phase noise over that frequency offset interval and can be readily related to the time jitter due to the phase noise within that offset frequency interval. Phase noise has a detrimental effect on the performance of ADCs, DACs, and RF mixers. It lowers the achievable dynamic range of the converters and mixers, although they are affected in somewhat different ways. Time Jitter Phase noise is a frequency domain phenomenon. In the time domain, the same effect is exhibited as time jitter. When observing a sine wave, the time of successive zero crossings is seen to vary. For a square wave, the time jitter is seen as a displacement of the edges from their ideal (regular) times of occurrence. In both cases, the variations in timing from the ideal are the time jitter. Since these variations are random in nature, the time jitter is specified in units of seconds root mean square (rms) or 1 sigma of the Gaussian distribution. Time jitter that occurs on a sampling clock for a DAC or an ADC decreases the SNR and dynamic range of the converter. A sampling clock with the lowest possible jitter provides the highest performance from a given converter. Additive Phase Noise It is the amount of phase noise that is attributable to the device or subsystem being measured. The phase noise of any external oscillators or clock sources has been subtracted. This makes it possible to predict the degree to which the device affects the total system phase noise when used in conjunction with the various oscillators and clock sources, each of which contribute their own phase noise to the total. In many cases, the phase noise of one element dominates the system phase noise. Additive Time Jitter It is the amount of time jitter that is attributable to the device or subsystem being measured. The time jitter of any external oscillators or clock sources has been subtracted. This makes it possible to predict the degree to which the device will affect the total system time jitter when used in conjunction with the various oscillators and clock sources, each of which contribute their own time jitter to the total. In many cases, the time jitter of the external oscillators and clock sources dominates the system time jitter. Rev. A | Page 14 of 28 Data Sheet AD9515 TYPICAL PERFORMANCE CHARACTERISTICS 0.3 0.5 LVPECL (DIV ON) + CMOS (DIV ON) POWER (W) LVPECL (DIV ON) 0.2 LVPECL (DIV = 1) 0.3 LVDS (DIV ON) 400 800 1200 OUTPUT FREQUENCY (MHz) 1600 STOP 5GHz 0 20 40 60 80 OUTPUT FREQUENCY (MHz) 100 Figure 10. Power vs. Frequency—LVPECL, CMOS Figure 8. Power vs. Frequency—LVPECL, LVDS START 300kHz 0.2 Figure 9. CLK Smith Chart (Evaluation Board) Rev. A | Page 15 of 28 120 05597-008 0.1 05597-009 LVPECL (DIV OFF) + CMOS (DIV OFF) 05597-097 POWER (W) 0.4 AD9515 Data Sheet 1.8 DIFFERENTIAL SWING (V p-p) 1.7 1.6 1.5 1.4 HORIZ 200ps/DIV 1.2 100 600 1100 05597-012 VERT 500mV/DIV 05597-095 1.3 1600 OUTPUT FREQUENCY (MHz) Figure 14. LVPECL Differential Output Swing vs. Frequency Figure 11. LVPECL Differential Output @ 1600 MHz DIFFERENTIAL SWING (mV p-p) 750 600 550 500 100 300 500 700 OUTPUT FREQUENCY (MHz) 05597-013 HORIZ 500ps/DIV 650 05597-010 VERT 100mV/DIV 700 900 Figure 15. LVDS Differential Output Swing vs. Frequency Figure 12. LVDS Differential Output @ 800 MHz 3.5 2pF 3.0 2.5 OUTPUT (VPK) 10pF 2.0 1.5 1.0 20pF HORIZ 1ns/DIV Figure 13. CMOS Single-Ended Output @ 250 MHz with 10 pF Load 0 0 100 200 300 400 OUTPUT FREQUENCY (MHz) 500 600 Figure 16. CMOS Single-Ended Output Swing vs. Frequency and Load Rev. A | Page 16 of 28 05597-014 VERT 500mV/DIV 05597-011 0.5 AD9515 –110 –120 –120 –130 –130 –140 –140 –150 –150 –160 –160 1k 10k 100k 1M 10M OFFSET (Hz) –170 10 –90 –100 –100 –110 –110 L(f) (dBc/Hz) –90 –120 –130 –150 –150 –160 –160 100k 1M 10M OFFSET (Hz) –170 10 –110 –120 –120 L(f) (dBc/Hz) –110 –130 –140 –160 –160 100k 1M 10M OFFSET (Hz) 10k 100k 1M 10M –140 –150 10k 1k –130 –150 05597-045 L(f) (dBc/Hz) –100 1k 100 Figure 21. Additive Phase Noise—LVDS, Divide = 2, 122.88 MHz –100 100 10M OFFSET (Hz) Figure 18. Additive Phase Noise—LVDS, Divide = 1, 245.76 MHz –170 10 1M –130 –140 10k 100k –120 –140 05597-048 L(f) (dBc/Hz) –80 1k 10k Figure 20. Additive Phase Noise—LVPECL, Divide = 1, 622.08 MHz –80 100 1k OFFSET (Hz) Figure 17. Additive Phase Noise—LVPECL, Divide = 1, 245.76 MHz –170 10 100 05597-049 100 –170 10 Figure 19. Additive Phase Noise—CMOS, Divide = 1, 245.76 MHz 100 1k 10k 100k 1M 10M OFFSET (Hz) Figure 22. Additive Phase Noise—CMOS, Divide = 4, 61.44 MHz Rev. A | Page 17 of 28 05597-046 –170 10 05597-052 L(f) (dBc/Hz) –110 05597-051 L(f) (dBc/Hz) Data Sheet AD9515 Data Sheet FUNCTIONAL DESCRIPTION 3.3V OVERALL 3.1V OUT1 includes an analog delay block that can be set to add an additional delay of 1.5 ns, 5 ns, or 10 ns full scale, each with 16 levels of fine adjustment. 2.2V 35ms MAX VS 0V CLK CLOCK FREQUENCY IS EXAMPLE ONLY OUT DIVIDE = 2 PHASE = 0 < 65ms 05597-094 The AD9515 provides for the distribution of its input clock on one or both of its outputs. OUT0 is an LVPECL output. OUT1 can be set to either LVDS or CMOS logic levels. Each output has its own divider that can be set for a divide ratio selected from a list of integer values from 1 (bypassed) to 32. INTERNAL SYNC NODE CLK, CLKB—DIFFERENTIAL CLOCK INPUT Figure 24. Power-On Sync Timing The CLK and CLKB pins are differential clock input pins. This input works up to 1600 MHz. The jitter performance is degraded by a slew rate below 1 V/ns. The input level should be between approximately 150 mV p-p to no more than 2 V p-p. Anything greater can result in turning on the protection diodes on the input pins. See Figure 23 for the CLK equivalent input circuit. This input is fully differential and self-biased. The signal should be ac-coupled using capacitors. If a single-ended input must be used, this can be accommodated by ac coupling to one side of the differential input only. The other side of the input should be bypassed to a quiet ac ground by a capacitor. If the setup configuration of the AD9515 is changed during operation, the outputs can become unsynchronized. The outputs can be re-synchronized to each other at any time. Synchronization occurs when the SYNCB pin is pulled low and released. The clock outputs (except where divide = 1) are forced into a fixed state (determined by the divide and phase settings) and held there in a static condition, until the SYNCB pin is returned to high. Upon release of the SYNCB pin, after four cycles of the clock signal at CLK, all outputs continue clocking in synchronicity (except where divide = 1). When divide = 1 for an output, that output is not affected by SYNCB. CLOCK INPUT STAGE VS SYNCB 3 CLK CYCLES 4 CLK CYCLES OUT EXAMPLE: DIVIDE 8 PHASE = 0 EXAMPLE DIVIDE RATIO PHASE = 0 SYNCB CLKB 2.5k Figure 25. SYNCB Timing with Clock Present 5k 05597-021 5k 4 CLK CYCLES CLK OUT DEPENDS ON PREVIOUS STATE § § § EXAMPLE DIVIDE RATIO PHASE = 0 Figure 23. Clock Input Equivalent Circuit SYNCB MIN 5ns SYNCHRONIZATION § DEPENDS ON PREVIOUS STATE AND DIVIDE RATIO Figure 26. SYNCB Timing with No Clock Present Power-On SYNC A power-on sync (POS) is issued when the VS power supply is turned on to ensure that the outputs start in synchronization. The power-on sync works only if the VS power supply transitions the region from 2.2 V to 3.1 V within 35 ms. The POS can occur up to 65 ms after VS crosses 2.2 V. Only outputs which are not divide = 1 are synchronized. The outputs of the AD9515 can be synchronized by using the SYNCB pin. Synchronization aligns the phases of the clock outputs, respecting any phase offset that has been set on an output’s divider. 05597-022 SYNCB Figure 27. SYNCB Equivalent Input Circuit Rev. A | Page 18 of 28 05597-092 2.5k 05597-093 CLK CLK Data Sheet AD9515 Synchronization is initiated by pulling the SYNCB pin low for a minimum of 5 ns. The input clock does not have to be present at the time the command is issued. The synchronization occurs after four input clock cycles. provided by the VREF pin. All setup pins requiring the ⅔VS level must be tied to the VREF pin. VS The synchronization applies to clock outputs: that are not turned OFF where the divider is not divide = 1 (divider bypassed) SETUP PIN S0 TO S10 30k An output with its divider set to divide = 1 (divider bypassed) is always synchronized with the input clock, with a propagation delay. The SYNCB pin must be pulled up for normal operation. Do not let the SYNCB pin float. RSET RESISTOR The internal bias currents of the AD9515 are set by the RSET resistor. This resistor should be as close as possible to the value given as a condition in the Specifications section (RSET = 4.12 kΩ). This is a standard 1% resistor value and should be readily obtainable. The bias currents set by this resistor determine the logic levels and operating conditions of the internal blocks of the AD9515. The performance figures given in the Specifications section assume that this resistor value is used for RSET. VREF The VREF pin provides a voltage level of ⅔ VS. This voltage is one of the four logic levels used by the setup pins (S0 to S10). These pins set the operation of the AD9515. The VREF pin provides sufficient drive capability to drive as many of the setup pins as necessary, up to all on a single part. The VREF pin should be used for no other purpose. SETUP CONFIGURATION The specific operation of the AD9515 is set by the logic levels applied to the setup pins (S10 to S0). These pins use four-state logic. The logic levels used are VS and GND, plus ⅓ VS and ⅔ VS. The ⅓ VS level is provided by the internal self-biasing on each of the setup pins (S10 to S0). This is the level seen by a setup pin that is left not connected (NC). The ⅔ VS level is 05597-023 60k Figure 28. Setup Pin (S0 to S10) Equivalent Circuit The AD9515 operation is determined by the combination of logic levels present at the setup pins. The setup configurations for the AD9515 are shown in Table 10 to Table 15. The four logic levels are referred to as 0, ⅓, ⅔, and 1. These numbers represent the fraction of the VS voltage that defines the logic levels. See the setup pin thresholds in Table 6. The meaning of some of the setup pins depends on the logic level set on other pins. For example, the effect of the S9/S10 pair of pins depends on the state of S8. S8 selects whether the phase value selected by S9/S10 affects either OUT0 or OUT1. In addition, if OUT1 is selected to have its phase controlled, the effect further depends on the state of S0. If S = 0, the delay block for OUT1 is bypassed, and the logic levels on S9/S10 set the phase value of the OUT1 divider. However, if S0 ≠ 0, then the full-scale delay for OUT1 is set by the logic level on S0, and S9/S10 set the delay block fine delay (fraction of full scale). Additionally, if a nonzero phase value is selected by S2/S3/S4 (for OUT0) or S5/S6/S7 (for OUT1), this phase overrides the phase value selected by S9/S10. This allows a phase delay to be selected on OUT0 while also selecting a time delay on OUT1. S1 selects the logic level of each output. OUT0 is LVPECL. The LVPECL output differential voltage (VOD) can be selected from two levels: 400 mV or 780 mV. OUT1 can be set to either LVDS or CMOS levels. OUT0 can be turned off (powered down) by setting S2/S3/S4 to 0/1/0. OUT1 can be turned off by setting S5/S6/S7 to 0/1/0. Do not set S2/S3/S4/S5/S6/S7 to 1/1/1/1/1/1. Rev. A | Page 19 of 28 AD9515 Data Sheet PROGRAMMING Table 10. S0—OUT1 Delay Full Scale S0 0 1/3 2/3 1 Delay Bypassed 1.5 ns 5 ns 10 ns Table 11. S1—Output Logic Configuration S1 0 1/3 2/3 1 OUT0 LVPECL 790 mV LVPECL 400 mV LVPECL 790 mV LVPECL 400 mV OUT1 LVDS LVDS CMOS CMOS Table 12. S2, S3, and S4—OUT0 S2 S3 S4 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 0 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 0 0 0 0 1/3 1/3 1/3 1/3 2/3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 OUT0 Divide (Duty Cycle1) 1 2 (50%) 3 (33%) 4 (50%) 5 (40%) 6 (50%) 7 (43%) 8 (50%) 9 (44%) 10 (50%) 11 (45%) 12 (50%) OUT0 OFF 14 (50%) 15 (47%) 16 (50%) 17 (47%) 18 (50%) 19 (47%) 20 (50%) 21 (48%) 22 (50%) 23 (48%) 24 (50%) 25 (48%) OUT0 Phase 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 S2 S3 S4 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 2/3 2/3 2/3 1 1 1 1 0 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 0 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 1/3 1/3 1/3 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 OUT0 Divide (Duty Cycle1) 26 (50%) 27 (48%) 28 (50%) 29 (48%) 30 (50%) 31 (48%) 32 (50%) 2 (50%) 4 (50%) 4 (50%) 4 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 32 (50%) 32 (50%) 32 (50%) 32 (50%) 32 (50%) Do not use OUT0 Phase 0 0 0 0 0 0 0 1 1 2 3 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 Duty cycle is the clock signal high time divided by the total period. Rev. A | Page 20 of 28 Data Sheet AD9515 Table 13. S5, S6, and S7—OUT1 S5 S6 S7 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 0 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 0 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 0 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 1 OUT1 Divide (Duty Cycle1) 1 2 (50%) 3 (33%) 4 (50%) 5 (40%) 6 (50%) 7 (43%) 8 (50%) 9 (44%) 10 (50%) 11 (45%) 12 (50%) OUT1 OFF 14 (50%) 15 (47%) 16 (50%) 17 (47%) 18 (50%) 19 (47%) 20 (50%) 21 (48%) 22 (50%) 23 (48%) 24 (50%) 25 (48%) 26 (50%) 27 (48%) 28 (50%) 29 (48%) 30 (50%) 31 (48%) 32 (50%) 2 (50%) 4 (50%) 4 (50%) 4 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 8 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) OUT1 Phase 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2 3 1 2 3 4 5 6 7 1 2 3 4 5 6 S5 S6 S7 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 OUT1 Divide (Duty Cycle1) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 16 (50%) 32 (50%) 32 (50%) 32 (50%) 32 (50%) 32 (50%) Do not use OUT1 Phase 7 8 9 10 11 12 13 14 15 1 2 3 4 5 Duty cycle is the clock signal high time divided by the total period. Table 14. S8—OUT0/OUT1 Phase (Delay) Select (Used with S9 to S10) S8 0 1/3 2/3 1 OUT0 No Phase Phase No Phase Phase (Start High) OUT1 (Delay if S0 ≠ 0) Phase (Delay) No Phase Phase (Delay) (Start High) No Phase Table 15. S9 and S10 S9 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 0 1/3 2/3 1 1 S10 0 0 0 0 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 1 1 1 1 OUT0 or OUT1 Phase (Depends on S8) Phase1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 OUT1 Delay (S0 ≠ 0) (Depends on S8) Fine Delay 0 1/16 1/8 3/16 1/4 5/16 3/8 7/16 1/2 9/16 5/8 11/16 3/4 13/16 7/8 15/16 A phase > 0 in Table 12 or overrides the phase in Table 15. Rev. A | Page 21 of 28 AD9515 Data Sheet DIVIDER PHASE OFFSET The phase offset of OUT0 and OUT1 can be selected (see Table 12 to Table 15). This allows the relative phase of OUT0 and OUT1 to be set. After a SYNC operation (see the Synchronization section), the phase offset word of each divider determines the number of input clock (CLK) cycles to wait before initiating a clock output edge. By giving each divider a different phase offset, output-tooutput delays can be set in increments of the fast clock period, tCLK. Figure 29 shows four cases, each with the divider set to divide = 4. By incrementing the phase offset from 0 to 3, the output is offset from the initial edge by a multiple of tCLK. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 CLOCK INPUT CLK DIVIDER OUTPUT DIV = 4 The resolution of the phase offset is set by the fast clock period (tCLK) at CLK. The maximum unique phase offset is less than the divide ratio, up to a phase offset of 15. Phase offsets can be related to degrees by calculating the phase step for a particular divide ratio: Phase Step = 360°/Divide Ratio Using some of the same examples: Divide = 4 Phase Step = 360°/4 = 90° Unique Phase Offsets in Degrees Are Phase = 0°, 90°, 180°, 270° Divide = 9 tCLK Phase Step = 360°/9 = 40° PHASE = 0 Unique Phase Offsets in Degrees Are Phase = 0°, 40°, 80°, 120°, 160°, 200°, 240°, 280°, 320° PHASE = 1 PHASE = 2 DELAY BLOCK PHASE = 3 OUT1 includes an analog delay element that gives variable time delays (ΔT) in the clock signal passing through that output. tCLK CLOCK INPUT 05597-024 2 × tCLK 3 × tCLK OUT1 ONLY Figure 29. Phase Offset—Divider Set for Divide = 4, Phase Set from 0 to 2 MUX ÷N ∅SELECT For example: LVDS CMOS ∆T FINE DELAY ADJUST (16 STEPS) FULL SCALE : 1.5ns, 5ns, 10ns tCLK = 1/491.52 = 2.0345 ns 05596-025 OUTPUT DRIVER CLK = 491.52 MHz Figure 30. Analog Delay Block For Divide = 4: The amount of delay that can be used is determined by the output frequency. The amount of delay is limited to less than one-half cycle of the clock period. For example, for a 10 MHz clock, the delay can extend to the full 10 ns maximum. However, for a 100 MHz clock, the maximum delay is less than 5 ns (or half of the period). Phase Offset 0 = 0 ns Phase Offset 1 = 2.0345 ns Phase Offset 2 = 4.069 ns Phase Offset 3 = 6.104 ns The AD9515 allows for the selection of three full-scale delays, 1.5 ns, 5 ns, and 10 ns, set by delay full scale (see Table 10). Each of these full-scale delays can be scaled by 16 fine adjustment values, which are set by the delay word (see Table 14 and Table 15). The outputs can also be described as: Phase Offset 0 = 0° Phase Offset 1 = 90° Phase Offset 2 = 180° Phase Offset 3 = 270° Setting the phase offset to Phase = 4 results in the same relative phase as Phase = 0° or 360°. The delay block adds some jitter to the output. This means that the delay function should be used primarily for clocking digital chips, such as FPGA, ASIC, DUC, and DDC, rather than for supplying a sample clock for data converters. The jitter is higher for longer full scales because the delay block uses a ramp and trip points to create the variable delay. A longer ramp means more noise has a chance of being introduced. Rev. A | Page 22 of 28 Data Sheet AD9515 When the delay block is OFF (bypassed), it is also powered down. POWER SUPPLY OUTPUTS The AD9515 offers three different output level choices: LVPECL, LVDS, and CMOS. OUT0/OUT0B offers an LVPECL differential output. The LVPECL differential voltage swing (VOD) can be selected as either 400 mV or 790 mV (see Table 11). OUT1/OUT1B can be selected as either an LVDS differential output or a pair of CMOS single-ended outputs. If selected as CMOS, OUT1 is a noninverted, single-ended output, and OUT1B is an inverted, single-ended output. 3.3V The AD9515 requires a 3.3 V ± 5% power supply for VS. The tables in the Specifications section give the performance expected from the AD9515 with the power supply voltage within this range. In no case should the absolute maximum range of −0.3 V to +3.6 V, with respect to GND, be exceeded on Pin VS. Good engineering practice should be followed in the layout of power supply traces and the ground plane of the PCB. The power supply should be bypassed on the PCB with adequate capacitance (>10 µF). The AD9515 should be bypassed with adequate capacitors (0.1 µF) at all power pins as close as possible to the part. The layout of the AD9515 evaluation board (AD9515/PCB) is a good example. OUT 05597-026 OUTB GND Figure 31. LVPECL Output Simplified Equivalent Circuit 3.5mA OUT 05597-027 OUTB 3.5mA Figure 32. LVDS Output Simplified Equivalent Circuit VS 05597-028 OUT1/ OUT1B Figure 33. CMOS Equivalent Output Circuit Rev. A | Page 23 of 28 AD9515 Data Sheet Exposed Metal Paddle POWER MANAGEMENT The exposed metal paddle on the AD9515 package is an electrical connection, as well as a thermal enhancement. For the device to function properly, the paddle must be properly attached to ground (GND). In some cases, the AD9515 can be configured to use less power by turning off functions that are not being used. The exposed paddle of the AD9515 package must be soldered down. The AD9515 must dissipate heat through its exposed paddle. The PCB acts as a heat sink for the AD9515. The PCB attachment must provide a good thermal path to a larger heat dissipation area, such as a ground plane on the PCB. This requires a grid of vias from the top layer down to the ground plane (see Figure 34). The AD9515 evaluation board (AD9515/PCB)provides a good example of how the part should be attached to the PCB. • A divider is powered down when set to divide = 1 (bypassed). • Adjustable delay block on OUT1 is powered down when in off mode (S0 = 0). • An unneeded output can be powered down (see Table 12 and Table 13). This also powers down the divider for that output. The power-saving options include the following: 05597-035 VIAS TO GND PLANE Figure 34. PCB Land for Attaching Exposed Paddle Rev. A | Page 24 of 28 Data Sheet AD9515 APPLICATIONS USING THE AD9515 OUTPUTS FOR ADC CLOCK APPLICATIONS Any high speed, analog-to-digital converter (ADC) is extremely sensitive to the quality of the sampling clock provided by the user. An ADC can be thought of as a sampling mixer, and any noise, distortion, or timing jitter on the clock is combined with the desired signal at the A/D output. Clock integrity requirements scale with the analog input frequency and resolution, with higher analog input frequency applications at ≥14-bit resolution being the most stringent. The theoretical SNR of an ADC is limited by the ADC resolution and the jitter on the sampling clock. Considering an ideal ADC of infinite resolution where the step size and quantization error can be ignored, the available SNR can be expressed approximately by 1 SNR = 20 × log 2πft J where f is the highest analog frequency being digitized. tj is the rms jitter on the sampling clock. Figure 35 shows the required sampling clock jitter as a function of the analog frequency and effective number of bits (ENOB). 110 LVPECL CLOCK DISTRIBUTION The low voltage, positive emitter-coupled, logic (LVPECL) outputs of the AD9515 provide the lowest jitter clock signals available from the AD9515. The LVPECL outputs (because they are open emitter) require a dc termination to bias the output transistors. The simplified equivalent circuit in Figure 31 shows the LVPECL output stage. In most applications, a standard LVPECL far-end termination is recommended, as shown in Figure 36. The resistor network is designed to match the transmission line impedance (50 Ω) and the switching threshold (VS − 1.3 V). 18 VS 16 VS 90 400 70 fS 12 1ps 60 2ps LVPECL 50 83Ω Figure 36. LVPECL Far-End Termination 05597-091 6 100 83Ω 8 40 30 10 LVPECL 50Ω VT = VS – 1.3V s 127Ω SINGLE-ENDED (NOT COUPLED) 10 10p 127Ω 14 fS ENOB SNR (dB) 80 VS 50Ω 05597-030 TJ = 100 fS 200 1k fA FULL-SCALE SINE WAVE ANALOG FREQUENCY (MHz) VS VS 0.1nF Figure 35. ENOB and SNR vs. Analog Input Frequency See Application Notes AN-756 and AN-501 at www.analog.com. LVPECL 0.1nF 200Ω 100Ω DIFFERENTIAL 100Ω (COUPLED) LVPECL 200Ω Figure 37. LVPECL with Parallel Transmission Line Rev. A | Page 25 of 28 05597-031 1 SNR = 20log 2πf T A J 100 Many high performance ADCs feature differential clock inputs to simplify the task of providing the required low jitter clock on a noisy PCB. (Distributing a single-ended clock on a noisy PCB can result in coupled noise on the sample clock. Differential distribution has inherent common-mode rejection that can provide superior clock performance in a noisy environment.) The AD9515 features both LVPECL and LVDS outputs that provide differential clock outputs, which enable clock solutions that maximize converter SNR performance. The input requirements of the ADC (differential or single-ended, logic level, termination) should be considered when selecting the best clocking/converter solution. AD9515 Data Sheet LVDS CLOCK DISTRIBUTION Termination at the far end of the PCB trace is a second option. The CMOS outputs of the AD9515 do not supply enough current to provide a full voltage swing with a low impedance resistive, far-end termination, as shown in Figure 40. The far-end termination network should match the PCB trace impedance and provide the desired switching point. The reduced signal swing may still meet receiver input requirements in some applications. This can be useful when driving long trace lengths on less critical nets. The AD9515 provides one clock output (OUT2) that is selectable as either CMOS or LVDS levels. Low voltage differential signaling (LVDS) is a differential output option for OUT2. LVDS uses a current mode output stage. The current is 3.5 mA, which yields 350 mV output swing across a 100 Ω resistor. The LVDS output meets or exceeds all ANSI/TIA/EIA-644 specifications. A recommended termination circuit for the LVDS outputs is shown in Figure 38. VS VS VS 10Ω 50Ω 100Ω CMOS OUT1/OUT1B SELECTED AS CMOS LVDS Figure 38. LVDS Output Termination See Application Note AN-586 at www.analog.com for more information on LVDS. CMOS CLOCK DISTRIBUTION The AD9515 provides one output (OUT1) that is selectable as either CMOS or LVDS levels. When selected as CMOS, this output provides for driving devices requiring CMOS level logic at their clock inputs. Whenever single-ended CMOS clocking is used, some of the following general guidelines should be used. Point-to-point nets should be designed such that a driver has only one receiver on the net, if possible. This allows for simple termination schemes and minimizes ringing due to possible mismatched impedances on the net. Series termination at the source is generally required to provide transmission line matching and/or to reduce current transients at the driver. The value of the resistor is dependent on the board design and timing requirements (typically 10 Ω to 100 Ω is used). CMOS outputs are also limited in terms of the capacitive load or trace length that they can drive. Typically, trace lengths less than 3 inches are recommended to preserve signal rise/fall times and preserve signal integrity. 10Ω Because of the limitations of single-ended CMOS clocking, consider using differential outputs when driving high speed signals over long traces. The AD9515 offers both LVPECL and LVDS outputs that are better suited for driving long traces where the inherent noise immunity of differential signaling provides superior performance for clocking converters. SETUP PINS (S0 TO S10) The setup pins that require a logic level of ⅓ VS (internal selfbias) should be tied together and bypassed to ground via a capacitor. The setup pins that require a logic level of ⅔ VS should be tied together, along with the VREF pin, and bypassed to ground via a capacitor. POWER AND GROUNDING CONSIDERATIONS AND POWER SUPPLY REJECTION Many applications seek high speed and performance under less than ideal operating conditions. In these application circuits, the implementation and construction of the PCB is as important as the circuit design. Proper RF techniques must be used for device selection, placement, and routing, as well as power supply bypassing and grounding to ensure optimum performance. CMOS 05597-033 MICROSTRIP GND 3pF Figure 40. CMOS Output with Far-End Termination 60.4Ω 1.0 INCH 5pF 100Ω 05597-034 100Ω 100Ω DIFFERENTIAL (COUPLED) 05597-032 LVDS Figure 39. Series Termination of CMOS Output Rev. A | Page 26 of 28 Data Sheet AD9515 PHASE NOISE AND JITTER MEASUREMENT SETUPS WENZEL OSCILLATOR EVALUATION BOARD BALUN SPLITTER ZESC-2-11 OUT1 TERM AMP OUT1B TERM +28dB CLK1 ATTENUATOR –12dB SIG IN ATTENUATOR –7dB REF IN 0° EVALUATION BOARD ZFL1000VH2 OUT1 TERM AMP OUT1B TERM +28dB CLK1 VARIABLE DELAY COLBY PDL30A 0.01ns STEP TO 10ns 05597-041 BALUN AD9515 AGILENT E5500B PHASE NOISE MEASUREMENT SYSTEM ZFL1000VH2 AD9515 Figure 41. Additive Phase Noise Measurement Configuration WENZEL OSCILLATOR ANALOG SOURCE EVALUATION BOARD PC AD9515 BALUN WENZEL OSCILLATOR OUT1 TERM OUT1B TERM CLK SNR ADC CLK1 FFT 05597-042 tJ_RMS DATA CAPTURE CARD FIFO Figure 42. Jitter Determination by Measuring SNR of ADC 2 t J_RMS = V A_RMS − SND × BW 2 − θ QUANTIZATION 2 + θ THERMAL 2 + θ DNL 2 SNR 10 20 2 2π × f A × V A_PK ( ) ( [ ] where: tj_RMS is the rms time jitter. SNR is the signal-to-noise ratio. SND is the source noise density in nV/√Hz. BW is the SND filter bandwidth. VA is the analog source voltage. fA is the analog frequency. The θ terms are the quantization, thermal, and DNL errors. Rev. A | Page 27 of 28 ) AD9515 Data Sheet OUTLINE DIMENSIONS 5.00 BSC SQ 0.60 MAX 0.60 MAX 25 32 1 24 0.50 BSC 3.25 3.10 SQ 2.95 EXPOSED PAD 17 TOP VIEW 1.00 0.85 0.80 SEATING PLANE 12° MAX 0.80 MAX 0.65 TYP 0.30 0.25 0.18 0.50 0.40 0.30 0.05 MAX 0.02 NOM COPLANARITY 0.08 0.20 REF 8 16 9 BOTTOM VIEW 0.25 MIN 3.50 REF FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2 03-28-2012-A 4.75 BSC SQ PIN 1 INDICATOR PIN 1 INDICATOR Figure 43. 32-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 5 mm × 5 mm Body, Very Thin Quad (CP-32-2) Dimensions shown in millimeters ORDERING GUIDE Model1 AD9515BCPZ AD9515BCPZ-REEL7 AD9515/PCBZ 1 Temperature Range −40°C to +85°C −40°C to +85°C Package Description 32-Lead Lead Frame Chip Scale Package (LFCSP_VQ) 32-Lead Lead Frame Chip Scale Package (LFCSP_VQ) Evaluation Board Z = RoHS Compliant Part. ©2005–2012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05597-0-4/12(A) Rev. A | Page 28 of 28 Package Option CP-32-2 CP-32-2