14-Bit, 170 MSPS/210 MSPS/250 MSPS, 1.8 V Dual Analog-to-Digital Converter (ADC) AD9643 FEATURES FUNCTIONAL BLOCK DIAGRAM AVDD VIN+A PIPELINE 14-BIT ADC VIN–A VCM AGND PIPELINE 14-BIT ADC VIN–B D0± 14 AD9643 VIN+B DRVDD 14 PARALLEL DDR LVDS AND DRIVERS . . . . . D13± DCO± REFERENCE OR± 1 TO 8 CLOCK DIVIDER SERIAL PORT OEB PDWN SCLK SDIO CSB CLK+ CLK– SYNC NOTES 1. THE D0± TO D13± PINS REPRESENT BOTH THE CHANNEL A AND CHANNE L B LVDS OUTPUT DATA. 09636-001 SNR = 70.6 dBFS at 185 MHz AIN and 250 MSPS SFDR = 85 dBc at 185 MHz AIN and 250 MSPS −151.6 dBFS/Hz input noise at 185 MHz, −1 dBFS AIN and 250 MSPS Total power consumption: 785 mW at 250 MSPS 1.8 V supply voltages LVDS (ANSI-644 levels) outputs Integer 1-to-8 input clock divider (625 MHz maximum input) Sample rates of up to 250 MSPS IF sampling frequencies of up to 400 MHz Internal ADC voltage reference Flexible analog input range 1.4 V p-p to 2.0 V p-p (1.75 V p-p nominal) ADC clock duty cycle stabilizer 95 dB channel isolation/crosstalk Serial port control Energy saving power-down modes User-configurable, built-in self-test (BIST) capability Figure 1. APPLICATIONS Communications Diversity radio systems Multimode digital receivers (3G) TD-SCDMA, WiMax, WCDMA, CDMA2000, GSM, EDGE, LTE I/Q demodulation systems Smart antenna systems General-purpose software radios Ultrasound equipment Broadband data applications GENERAL DESCRIPTION The AD9643 is a dual, 14-bit analog-to-digital converter (ADC) with sampling speeds of up to 250 MSPS. The AD9643 is designed to support communications applications, where low cost, small size, wide bandwidth, and versatility are desired. The dual ADC cores feature a multistage, differential pipelined architecture with integrated output error correction logic. Each ADC features wide bandwidth inputs supporting a variety of user-selectable input ranges. An integrated voltage reference eases design considerations. A duty cycle stabilizer is provided to compensate for variations in the ADC clock duty cycle, allowing the converters to maintain excellent performance. The ADC output data is routed directly to the two external 14-bit LVDS output ports and formatted as either interleaved or channel multiplexed. Flexible power-down options allow significant power savings, when desired. Programming for setup and control are accomplished using a 3-wire SPI-compatible serial interface. The AD9643 is available in a 64-lead LFCSP and is specified over the industrial temperature range of −40°C to +85°C. This product is protected by a U.S. patent. PRODUCT HIGHLIGHTS 1. Integrated dual, 14-bit, 170 MSPS/210 MSPS/250 MSPS ADCs. 2. Operation from a single 1.8 V supply and a separate digital output driver supply accommodating LVDS outputs. 3. Proprietary differential input maintains excellent SNR performance for input frequencies of up to 400 MHz. 4. SYNC input allows synchronization of multiple devices. 5. 3-pin, 1.8 V SPI port for register programming and register readback. 6. Pin compatibility with the AD9613, allowing a simple migration down from 14 bits to 12 bits. This part is also pin compatible with the AD6649 and the AD6643. 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 ©2011 Analog Devices, Inc. All rights reserved. AD9643 TABLE OF CONTENTS Features .............................................................................................. 1 Analog Input Considerations ................................................... 23 Applications ....................................................................................... 1 Voltage Reference ....................................................................... 25 Functional Block Diagram .............................................................. 1 Clock Input Considerations ...................................................... 25 General Description ......................................................................... 1 Power Dissipation and Standby Mode .................................... 26 Product Highlights ........................................................................... 1 Digital Outputs ........................................................................... 27 Revision History ............................................................................... 2 Channel/Chip Synchronization .................................................... 28 Specifications..................................................................................... 3 Serial Port Interface (SPI) .............................................................. 29 ADC DC Specifications ............................................................... 3 Configuration Using the SPI ..................................................... 29 ADC AC Specifications ............................................................... 4 Hardware Interface..................................................................... 29 Digital Specifications ................................................................... 6 SPI Accessible Features .............................................................. 30 Switching Specifications .............................................................. 8 Memory Map .................................................................................. 31 Timing Specifications .................................................................. 9 Reading the Memory Map Register Table............................... 31 Absolute Maximum Ratings.......................................................... 11 Memory Map Register Table ..................................................... 32 Thermal Characteristics ............................................................ 11 Memory Map Register Description ......................................... 34 ESD Caution ................................................................................ 11 Applications Information .............................................................. 35 Pin Configurations and Function Descriptions ......................... 12 Design Guidelines ...................................................................... 35 Typical Performance Characteristics ........................................... 16 Outline Dimensions ....................................................................... 36 Equivalent Circuits ......................................................................... 22 Ordering Guide .......................................................................... 36 Theory of Operation ...................................................................... 23 ADC Architecture ...................................................................... 23 REVISION HISTORY 5/11—Rev. 0 to Rev. A Changes to Table 2, Worst Other (Harmonic or Spur) Max Values......................................................................................... 4 4/11—Revision 0: Initial Version Rev. A | Page 2 of 36 AD9643 SPECIFICATIONS ADC DC SPECIFICATIONS AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.75 V p-p full-scale input range, duty cycle stabilizer (DCS) enabled, unless otherwise noted. Table 1. Parameter RESOLUTION ACCURACY No Missing Codes Offset Error Gain Error Differential Nonlinearity (DNL) Integral Nonlinearity (INL) 1 MATCHING CHARACTERISTIC Offset Error Gain Error TEMPERATURE DRIFT Offset Error Gain Error INPUT REFERRED NOISE VREF = 1.0 V ANALOG INPUT Input Span Input Capacitance 2 Input Resistance 3 Input Common-Mode Voltage POWER SUPPLIES Supply Voltage AVDD DRVDD Supply Current IAVDD1 IDRVDD1 POWER CONSUMPTION Sine Wave Input (DRVDD = 1.8 V) Standby Power 4 Power-Down Power Temperature Full Min 14 Full Full Full Full 25°C Full 25°C AD9643-170 Typ Max Min 14 Guaranteed AD9643-210 Typ Max Guaranteed ±10 +2/−6 ±0.75 AD9643-250 Typ Max ±10 ±4 ±0.75 ±0.25 ±1.8 ±0.25 ±2 ±1.5 ±3.5 ±1.5 ±13 ±2.5/ +3.5 Unit Bits Guaranteed ±10 +3/−5 ±0.75 ±0.25 Full Full Min 14 ±1.5 ±13 −2/ +3.5 ±13 −2.5/ +3.5 mV %FSR LSB LSB LSB LSB mV %FSR Full Full ±15 ±50 ±15 ±50 ±15 ±50 ppm/°C ppm/°C 25°C 1.33 1.33 1.33 LSB rms Full Full Full Full 1.75 2.5 20 0.9 1.75 2.5 20 0.9 1.75 2.5 20 0.9 V p-p pF kΩ V Full Full 1.7 1.7 1.8 1.8 1.9 1.9 Full Full 196 145 250 160 Full Full Full 614 90 10 1.7 1.7 1 1.8 1.8 1.9 1.9 217 160 265 185 680 90 10 Measured with a low input frequency, full-scale sine wave. Input capacitance refers to the effective capacitance between one differential input pin and its complement. Input resistance refers to the effective resistance between one differential input pin and its complement. 4 Standby power is measured with a dc input and the CLK pin inactive (that is, set to AVDD or AGND). 2 3 Rev. A | Page 3 of 36 1.7 1.7 1.8 1.8 1.9 1.9 V V 256 180 275 210 mA mA 785 90 10 mW mW mW AD9643 ADC AC SPECIFICATIONS AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.75 V p-p full-scale input range, unless otherwise noted. Table 2. Parameter 1 SIGNAL-TO-NOISE-RATIO (SNR) fIN = 30 MHz fIN = 90 MHz Temperature 25°C 25°C Full Min AD9643-170 Typ Max Min 72.2 72.0 70.4 AD9643-210 Typ Max Min AD9643-250 Typ Max 72.2 72.0 72.0 71.7 dBFS dBFS dBFS dBFS 69.9 fIN = 140 MHz 25°C 71.8 71.6 71.4 fIN = 185 MHz 25°C 71.4 71.2 70.9 Full fIN = 220 MHz SIGNAL-TO-NOISE AND DISTORTION (SINAD) fIN = 30 MHz fIN = 90 MHz fIN = 140 MHz fIN = 185 MHz fIN = 185 MHz fIN = 220 MHz WORST SECOND OR THIRD HARMONIC fIN = 30 MHz fIN = 90 MHz fIN = 140 MHz fIN = 185 MHz fIN = 220 MHz SPURIOUS-FREE DYNAMIC RANGE (SFDR) fIN = 30 MHz fIN = 90 MHz fIN = 140 MHz fIN = 185 MHz fIN = 220 MHz WORST OTHER (HARMONIC OR SPUR) fIN = 30 MHz fIN = 90 MHz fIN = 140 MHz fIN = 185 MHz fIN = 220 MHz TWO-TONE SFDR fIN = 184.12 MHz (−7 dBFS ), 187.12 MHz (−7 dBFS ) dBFS 68.8 dBFS 25°C 71.1 70.9 70.5 dBFS 25°C 25°C Full 25°C 25°C 71.2 71.0 71.2 71.0 71.0 70.7 70.8 70.4 70.6 70.2 70.4 69.9 dBFS dBFS dBFS dBFS dBFS 25°C 70.1 69.9 69.5 dBFS 25°C 25°C 25°C 25°C 11.5 11.5 11.5 11.4 11.5 11.5 11.5 11.4 11.5 11.5 11.4 11.3 Bits Bits Bits Bits 25°C 11.4 11.3 11.3 Bits 25°C 25°C Full 25°C 25°C Full 25°C −95 −92 −90 −90 −90 −88 dBc dBc dBc dBc dBc dBc dBc 25°C 25°C Full 25°C 25°C Full 25°C 70.4 69.9 Full fIN = 220 MHz EFFECTIVE NUMBER OF BITS (ENOB) fIN = 30 MHz fIN = 90 MHz fIN = 140 MHz Unit 67.5 −78 dBFS −80 −88 −83 −88 −87 −85 −85 −83 −85 −85 95 92 90 90 90 88 88 83 88 87 86 85 83 85 85 25°C 25°C Full 25°C 25°C Full 25°C −98 −97 −95 −95 −94 −93 25°C −80 78 dBc dBc dBc dBc dBc dBc dBc 80 80 −97 −96 −93 −92 −92 −92 −94 −90 −88 dBc dBc dBc dBc dBc dBc dBc 88 88 88 dBc −78 −80 −80 Rev. A | Page 4 of 36 AD9643 Parameter 1 CROSSTALK 2 FULL POWER BANDWIDTH 3 NOISE BANDWIDTH 4 Temperature Full 25°C 25°C Min AD9643-170 Typ Max 95 400 1000 1 Min AD9643-210 Typ Max 95 400 1000 Min See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for a complete set of definitions. Crosstalk is measured at 100 MHz with −1.0 dBFS on one channel and no input on the alternate channel. 3 Full power bandwidth is the bandwidth of operation in which proper ADC performance can be achieved. 4 Noise bandwidth is the −3 dB bandwidth for the ADC inputs across which noise can enter the ADC and is not attenuated internally. 2 Rev. A | Page 5 of 36 AD9643-250 Typ Max 95 400 1000 Unit dB MHz MHz AD9643 DIGITAL SPECIFICATIONS AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.75 V p-p full-scale input range, DCS enabled, unless otherwise noted. Table 3. Parameter DIFFERENTIAL CLOCK INPUTS (CLK+, CLK−) Logic Compliance Internal Common-Mode Bias Differential Input Voltage Input Voltage Range Input Common-Mode Range High Level Input Current Low Level Input Current Input Capacitance Input Resistance SYNC INPUT Logic Compliance Internal Bias Input Voltage Range High Level Input Voltage Low Level Input Voltage High Level Input Current Low Level Input Current Input Capacitance Input Resistance LOGIC INPUT (CSB) 1 High Level Input Voltage Low Level Input Voltage High Level Input Current Low Level Input Current Input Resistance Input Capacitance LOGIC INPUT (SCLK) 2 High Level Input Voltage Low Level Input Voltage High Level Input Current Low Level Input Current Input Resistance Input Capacitance LOGIC INPUTS (SDIO)1 High Level Input Voltage Low Level Input Voltage High Level Input Current Low Level Input Current Input Resistance Input Capacitance LOGIC INPUTS (OEB, PDWN)2 High Level Input Voltage Low Level Input Voltage High Level Input Current Low Level Input Current Input Resistance Input Capacitance Temp Min Full Full Full Full Full Full Full Full CMOS/LVDS/LVPECL 0.9 0.3 3.6 AGND AVDD 0.9 1.4 −10 +22 −22 −10 4 8 10 12 Full Full Full Full Full Full Full Full Rev. A | Page 6 of 36 Typ Max CMOS/LVDS 0.9 AGND 1.2 AGND −5 −5 12 Full Full Full Full Full Full 1.22 0 −5 −80 Full Full Full Full Full Full 1.22 0 45 −5 Full Full Full Full Full Full 1.22 0 45 −5 Full Full Full Full Full Full 1.22 0 45 −5 AVDD AVDD 0.6 +5 +5 1 16 20 V V p-p V V μA μA pF kΩ V V V V μA μA pF kΩ 2.1 0.6 +5 −45 V V μA μA kΩ pF 2.1 0.6 70 +5 V V μA μA kΩ pF 2.1 0.6 70 +5 V V μA μA kΩ pF 2.1 0.6 70 +5 V V μA μA kΩ pF 26 2 26 2 26 5 26 5 Unit AD9643 Parameter DIGITAL OUTPUTS LVDS Data and OR Outputs Differential Output Voltage (VOD), ANSI Mode Output Offset Voltage (VOS), ANSI Mode Differential Output Voltage (VOD), Reduced Swing Mode Output Offset Voltage (VOS), Reduced Swing Mode 1 2 Pull-up. Pull-down. Rev. A | Page 7 of 36 Temp Min Typ Max Unit Full Full 250 1.15 350 1.25 450 1.35 mV V Full Full 150 1.15 200 1.25 280 1.35 mV V AD9643 SWITCHING SPECIFICATIONS Table 4. Parameter CLOCK INPUT PARAMETERS Input Clock Rate Conversion Rate 1 CLK Period—Divide-by-1 Mode (tCLK) CLK Pulse Width High (tCH) Divide-by-1 Mode, DCS Enabled Divide-by-1 Mode, DCS Disabled Divide-by-2 Mode Through Divide-by-8 Mode Aperture Delay (tA) Aperture Uncertainty (Jitter, tJ) DATA OUTPUT PARAMETERS LVDS Mode Data Propagation Delay (tPD) DCO Propagation Delay (tDCO) DCO-to-Data Skew (tSKEW) Pipeline Delay (Latency) Aperture Delay (tA) Aperture Uncertainty (Jitter, tJ) Wake-Up Time (from Standby) Wake-Up Time (from Power-Down) Out-of-Range Recovery Time 1 Temp Min Full Full Full 40 5.8 Full Full Full 2.61 2.76 0.8 AD9643-170 Typ Max 625 170 2.9 2.9 3.19 3.05 Max AD9643-210 Typ Max 625 210 40 4.8 2.16 2.28 0.8 2.4 2.4 2.64 2.52 Min AD9643-250 Typ Max 40 4 1.8 1.9 0.8 2.0 2.0 Unit 625 250 MHz MSPS ns 2.2 2.1 ns ns ns Full Full 1.0 0.1 1.0 0.1 1.0 0.1 ns ps rms Full Full Full Full Full Full Full Full Full 4.8 5.5 0.7 10 1.0 0.1 10 250 3 4.8 5.5 0.7 10 1.0 0.1 10 250 3 4.8 5.5 0.7 10 1.0 0.1 10 250 3 ns ns ns Cycles ns ps rms μs μs Cycles 0.1 1.3 0.1 Conversion rate is the clock rate after the divider. Rev. A | Page 8 of 36 1.3 0.1 1.3 AD9643 TIMING SPECIFICATIONS Table 5. Parameter SYNC TIMING REQUIREMENTS tSSYNC tHSYNC SPI TIMING REQUIREMENTS tDS tDH tCLK tS tH tHIGH tLOW tEN_SDIO tDIS_SDIO Conditions Min SYNC to the rising edge of CLK setup time SYNC to the rising edge of CLK hold time Setup time between the data and the rising edge of SCLK Hold time between the data and the rising edge of SCLK Period of the SCLK Setup time between CSB and SCLK Hold time between CSB and SCLK Minimum period that SCLK should be in a logic high state Minimum period that SCLK should be in a logic low state Time required for the SDIO pin to switch from an input to an output relative to the SCLK falling edge Time required for the SDIO pin to switch from an output to an input relative to the SCLK rising edge Rev. A | Page 9 of 36 Typ 0.3 0.4 Max Unit ns ns 2 2 40 2 2 10 10 10 ns ns ns ns ns ns ns ns 10 ns AD9643 Timing Diagrams tA N–1 N+4 N+5 N N+3 VIN N+1 tCH N+2 tCLK CLK+ CLK– tDCO DCO– DCO+ tSKEW PARALLEL INTERLEAVED D0± (LSB) CH A N – 10 CH B N – 10 CH A N–9 CH B N–9 CH A N–8 CH B N–8 CH A N–7 CH B N–7 CH A N–6 D13± (MSB) CH A N – 10 CH B N – 10 CH A N–9 CH B N–9 CH A N–8 CH B N–8 CH A N–7 CH B N–7 CH A N–6 CHANNEL MULTIPLEXED D0±/D1± (EVEN/ODD) MODE (LSB) CH A0 N – 10 CH A1 N – 10 CH A0 N–9 CH A1 N–9 CH A0 N–8 CH A1 N–8 CH A0 N–7 CH A1 N–7 CH A0 N–6 D12±/D13± (MSB) CH A12 N – 10 CH A13 N – 10 CH A12 N–9 CH A13 N–9 CH A12 N–8 CH A13 N–8 CH A12 N–7 CH A13 N–7 CH A12 N–6 D0±/D1± (LSB) CH B0 N – 10 CH B1 N – 10 CH B0 N–9 CH B1 N–9 CH B0 N–8 CH B1 N–8 CH B0 N–7 CH B1 N–7 CH B0 N–6 CH B12 N – 10 CH B13 N – 10 CH B12 N–9 CH B13 N–9 CH B12 N–8 CH B13 N–8 CH B12 N–7 CH B13 N–7 CH B12 N–6 CHANNEL A AND CHANNEL B CHANNEL A CHANNEL B . . . . . . D12±/D13± (MSB) Figure 2. LVDS Modes for Data Output Timing CLK+ tSSYNC tHSYNC 09636-003 CHANNEL MULTIPLEXED (EVEN/ODD) MODE . . . SYNC Figure 3. SYNC Timing Inputs Rev. A | Page 10 of 36 09636-002 tPD AD9643 ABSOLUTE MAXIMUM RATINGS Table 6. Parameter Electrical AVDD to AGND DRVDD to AGND VIN+A/VIN+B, VIN−A/VIN−B to AGND CLK+, CLK− to AGND SYNC to AGND VCM to AGND CSB to AGND SCLK to AGND SDIO to AGND OEB to AGND PDWN to AGND OR+/OR− to AGND D0−/D0+ Through D13−/D13+ to AGND DCO+/DCO− to AGND Environmental Operating Temperature Range (Ambient) Maximum Junction Temperature Under Bias Storage Temperature Range (Ambient) THERMAL CHARACTERISTICS Rating −0.3 V to +2.0 V −0.3 V to +2.0 V −0.3 V to AVDD + 0.2 V −0.3 V to AVDD + 0.2 V −0.3 V to AVDD + 0.2 V −0.3 V to AVDD + 0.2 V −0.3 V to DRVDD + 0.3 V −0.3 V to DRVDD + 0.3 V −0.3 V to DRVDD + 0.3 V −0.3 V to DRVDD + 0.3 V −0.3 V to DRVDD + 0.3 V −0.3 V to DRVDD + 0.3 V −0.3 V to DRVDD + 0.3 V −0.3 V to DRVDD + 0.3 V −40°C to +85°C 150°C The exposed paddle must be soldered to the ground plane for the LFCSP package. This increases the reliability of the solder joints, maximizing the thermal capability of the package. Table 7. Thermal Resistance Package Type 64-Lead LFCSP 9 mm × 9 mm (CP-64-4) Airflow Velocity (m/sec) 0 1.0 2.0 θJA1, 2 26.8 21.6 20.2 θJC1, 3 1.14 θJB1, 4 10.4 Unit °C/W °C/W °C/W 1 Per JEDEC 51-7, plus JEDEC 25-5 2S2P test board. Per JEDEC JESD51-2 (still air) or JEDEC JESD51-6 (moving air). Per MIL-Std 883, Method 1012.1. 4 Per JEDEC JESD51-8 (still air). 2 3 Typical θJA is specified for a 4-layer PCB with a solid ground plane. As shown in Table 7, airflow increases heat dissipation, which reduces θJA. In addition, metal in direct contact with the package leads from metal traces, through holes, ground, and power planes, reduces the θJA. −65°C to +125°C ESD CAUTION 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. Rev. A | Page 11 of 36 AD9643 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 AVDD AVDD VIN+B VIN–B AVDD AVDD DNC VCM DNC DNC AVDD AVDD VIN–A VIN+A AVDD AVDD PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS PIN 1 INDICATOR 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 AD9643 PARALLEL LVDS TOP VIEW (Not to Scale) 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 PDWN OEB CSB SCLK SDIO OR+ OR– D13+ (MSB) D13– (MSB) D12+ D12– DRVDD D11+ D11– D10+ D10– NOTES 1. DNC = DO NOT CONNECT. DO NOT CONNECT TO THIS PIN. 2. THE EXPOSED THERMAL PADDLE ON THE BOTTOM OF THE PACKAGE PROVIDES THE ANALOG GROUND FOR THE PART. THIS EXPOSED PADDLE MUST BE CONNECTED TO GROUND FOR PROPER OPERATION. 09636-004 D4– D4+ DRVDD D5– D5+ D6– D6+ DCO– DCO+ D7– D7+ DRVDD D8– D8+ D9– D9+ 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 CLK+ CLK– SYNC DNC DNC DNC DNC (LSB) D0– (LSB) D0+ DRVDD D1– D1+ D2– D2+ D3– D3+ Figure 4. LFCSP Interleaved Parallel LVDS Pin Configuration (Top View) Table 8. Pin Function Descriptions for Interleaved Parallel LVDS Mode Pin No. ADC Power Supplies 10, 19, 28, 37 49, 50, 53, 54, 59, 60, 63, 64 4, 5, 6, 7, 55, 56, 58 0 ADC Analog 51 52 62 61 57 1 2 Digital Input 3 Digital Outputs 9 8 12 11 14 13 16 15 18 Mnemonic Type Description DRVDD AVDD DNC AGND, Exposed Paddle Supply Supply Digital Output Driver Supply (1.8 V Nominal). Analog Power Supply (1.8 V Nominal). Do Not Connect. Do not connect to this pin. Analog Ground. The exposed thermal paddle on the bottom of the package provides the analog ground for the part. This exposed paddle must be connected to ground for proper operation. VIN+A VIN−A VIN+B VIN−B VCM Input Input Input Input Output CLK+ CLK− Input Input Differential Analog Input Pin (+) for Channel A. Differential Analog Input Pin (−) for Channel A. Differential Analog Input Pin (+) for Channel B. Differential Analog Input Pin (−) for Channel B. Common-Mode Level Bias Output for Analog Inputs. This pin should be decoupled to ground using a 0.1 μF capacitor. ADC Clock Input—True. ADC Clock Input—Complement. SYNC Input Digital Synchronization Pin. Slave mode only. D0+ (LSB) D0− (LSB) D1+ D1− D2+ D2− D3+ D3− D4+ Output Output Output Output Output Output Output Output Output Channel A/Channel B LVDS Output Data 0—True. Channel A/Channel B LVDS Output Data 0—Complement. Channel A/Channel B LVDS Output Data 1—True. Channel A/Channel B LVDS Output Data 1—Complement. Channel A/Channel B LVDS Output Data 2—True. Channel A/Channel B LVDS Output Data 2—Complement. Channel A/Channel B LVDS Output Data 3—True. Channel A/Channel B LVDS Output Data 3—Complement. Channel A/Channel B LVDS Output Data 4—True. Ground Rev. A | Page 12 of 36 AD9643 Pin No. 17 21 20 23 22 27 26 30 29 32 31 34 33 36 35 39 38 41 40 43 42 25 24 SPI Control 45 44 46 Output Enable and Power-Down 47 48 Mnemonic D4− D5+ D5− D6+ D6− D7+ D7− D8+ D8− D9+ D9− D10+ D10− D11+ D11− D12+ D12− D13+ (MSB) D13− (MSB) OR+ OR− DCO+ DCO− Type Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Description Channel A/Channel B LVDS Output Data 4—Complement. Channel A/Channel B LVDS Output Data 5—True. Channel A/Channel B LVDS Output Data 5—Complement. Channel A/Channel B LVDS Output Data 6—True. Channel A/Channel B LVDS Output Data 6—Complement. Channel A/Channel B LVDS Output Data 7—True. Channel A/Channel B LVDS Output Data 7—Complement. Channel A/Channel B LVDS Output Data 8—True. Channel A/Channel B LVDS Output Data 8—Complement. Channel A/Channel B LVDS Output Data 9—True. Channel A/Channel B LVDS Output Data 9—Complement. Channel A/Channel B LVDS Output Data 10—True. Channel A/Channel B LVDS Output Data 10—Complement. Channel A/Channel B LVDS Output Data 11—True. Channel A/Channel B LVDS Output Data 11—Complement. Channel A/Channel B LVDS Output Data 12—True. Channel A/Channel B LVDS Output Data 12—Complement. Channel A/Channel B LVDS Output Data 13—True. Channel A/Channel B LVDS Output Data 13—Complement. Channel A/Channel B LVDS Overrange—True. Channel A/Channel B LVDS Overrange—Complement. Channel A/Channel B LVDS Data Clock Output—True. Channel A/Channel B LVDS Data Clock Output—Complement. SCLK SDIO CSB Input Input/Output Input SPI Serial Clock. SPI Serial Data I/O. SPI Chip Select (Active Low). OEB PDWN Input/Output Input/Output Output Enable Input (Active Low). Power-Down Input (Active High). The operation of this pin depends on the SPI mode and can be configured as power-down or standby (see Table 14). Rev. A | Page 13 of 36 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 AVDD AVDD VIN+B VIN–B AVDD AVDD DNC VCM DNC DNC AVDD AVDD VIN–A VIN+A AVDD AVDD AD9643 PIN 1 INDICATOR 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 AD9643 CHANNEL MULTIPLEXED (EVEN/ODD) LVDS TOP VIEW (Not to Scale) PDWN OEB CSB SCLK SDIO OR+ OR– A D12+/D13+ (MSB) A D12–/D13– (MSB) A D10+/D11+ A D10–/D11– DRVDD A D8+/D9+ A D8–/D9– A D6+/D7+ A D6–/D7– NOTES 1. DNC = DO NOT CONNECT. DO NOT CONNECT TO THIS PIN. 2. THE EXPOSED THERMAL PADDLE ON THE BOTTOM OF THE PACKAGE PROVIDES THE ANALOG GROUND FOR THE PART. THIS EXPOSED PADDLE MUST BE CONNECTED TO GROUND FOR PROPER OPERATION. 09636-005 B D8–/D9– B D8+/D9+ DRVDD B D10–/D11– B D10+/D11+ (MSB) B D12–/D13– (MSB) B D12+/D13+ DCO– DCO+ (LSB) A D0–/D1– (LSB) A D0+/D1+ DRVDD A D2–/D3– A D2+/D3+ A D4–/D5– A D4+/D5+ 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 CLK+ CLK– SYNC DNC DNC DNC DNC (LSB) B D0–/D1– (LSB) B D0+/D1+ DRVDD B D2–/D3– B D2+/D3+ B D4–/D5– B D4+/D5+ B D6–/D7– B D6+/D7+ Figure 5. LFCSP Channel Multiplexed (Even/Odd) LVDS Pin Configuration (Top View) Table 9. Pin Function Descriptions for Channel Multiplexed (Even/Odd) LVDS Mode Pin No. ADC Power Supplies 10, 19, 28, 37 49, 50, 53, 54, 59, 60, 63, 64 4, 5, 6, 7 0 ADC Analog 51 52 62 61 55 56 58 57 1 2 Digital Input 3 Digital Outputs 8 9 11 12 13 Mnemonic Type Description DRVDD AVDD DNC AGND, Exposed Paddle Supply Supply Digital Output Driver Supply (1.8 V Nominal). Analog Power Supply (1.8 V Nominal). Do Not Connect. Do not connect to this pin. Analog Ground. The exposed thermal paddle on the bottom of the package provides the analog ground for the part. This exposed paddle must be connected to ground for proper operation. VIN+A VIN−A VIN+B VIN−B DNC DNC DNC VCM Input Input Input Input CLK+ CLK− Input Input Differential Analog Input Pin (+) for Channel A. Differential Analog Input Pin (−) for Channel A. Differential Analog Input Pin (+) for Channel B. Differential Analog Input Pin (−) for Channel B. Do Not Connect. Do not connect to this pin. Do Not Connect. Do not connect to this pin. Do Not Connect. Do not connect to this pin. Common-Mode Level Bias Output for Analog Inputs. This pin should be decoupled to ground using a 0.1 μF capacitor. ADC Clock Input—True. ADC Clock Input—Complement. SYNC Input Digital Synchronization Pin. Slave mode only. B D0−/D1− (LSB) B D0+/D1+ (LSB) B D2−/D3− B D2+/D3+ B D4−/D5− Output Output Output Output Output Channel B LVDS Output Data 0/Data 1—Complement. Channel B LVDS Output Data 0/Data 1—True. Channel B LVDS Output Data 2/Data 3—Complement. Channel B LVDS Output Data 2/Data 3—True. Channel B LVDS Output Data 4/Data 5—Complement. Ground Output Rev. A | Page 14 of 36 AD9643 Pin No. 14 15 16 17 18 20 21 22 23 26 27 29 30 31 32 33 34 35 36 38 39 40 41 43 42 25 24 SPI Control 45 44 46 Output Enable and Power-Down 47 48 Mnemonic B D4+/D5+ B D6−/D7− B D6+/D7+ B D8−/D9− B D8+/D9+ B D10−/D11− B D10+/D11+ B D12−/D13− (MSB) B D12+/D13+ (MSB) A D0−/D1− (LSB) A D0+/D1+ (LSB) A D2−/D3− A D2+/D3+ A D4−/D5− A D4+/D5+ A D6−/D7− A D6+/D7+ A D8−/D9− A D8+/D9+ A D10−/D11− A D10+/D11+ A D12−/D13− (MSB) A D12+/D13+ (MSB) OR+ OR− DCO+ DCO− Type Output Output Output Output Output Output Output Output Description Channel B LVDS Output Data 4/Data 5—True. Channel B LVDS Output Data 6/Data 7—Complement. Channel B LVDS Output Data 6/Data 7—True. Channel B LVDS Output Data 8/Data 9—Complement. Channel B LVDS Output Data 8/Data 9—True. Channel B LVDS Output Data 10/Data 11—Complement. Channel B LVDS Output Data 10/Data 11—True. Channel B LVDS Output Data 12/Data 13—Complement. Output Channel B LVDS Output Data 12/Data 13—True. Output Output Output Output Output Output Output Output Output Output Output Output Output Channel A LVDS Output Data 0/Data 1—Complement. Channel A LVDS Output Data 0/Data 1—True. Channel A LVDS Output Data 2/Data 3—Complement. Channel A LVDS Output Data 2/Data 3—True. Channel A LVDS Output Data 4/Data 5—Complement. Channel A LVDS Output Data 4/Data 5—True. Channel A LVDS Output Data 6/Data 7—Complement. Channel A LVDS Output Data 6/Data 7—True. Channel A LVDS Output Data 8/Data 9—Complement. Channel A LVDS Output Data 8/Data 9—True. Channel A LVDS Output Data 10/Data 11—Complement. Channel A LVDS Output Data 10/Data 11—True. Channel A LVDS Output Data 12/Data 13—Complement. Output Channel A LVDS Output Data 12/Data 13—True. Output Output Output Output Channel A/Channel B LVDS Overrange Output—True. Channel A/Channel B LVDS Overrange Output—Complement. Channel A/Channel B LVDS Data Clock Output—True. Channel A/Channel B LVDS Data Clock Output—Complement. SCLK SDIO CSB Input Input/Output Input SPI Serial Clock. SPI Serial Data Input/Output. SPI Chip Select (Active Low). OEB PDWN Input Input Output Enable Input (Active Low). Power-Down Input (Active High). The operation of this pin depends on the SPI mode and can be configured as powerdown or standby (see Table 14). Rev. A | Page 15 of 36 AD9643 TYPICAL PERFORMANCE CHARACTERISTICS AVDD = 1.8 V, DRVDD = 1.8 V, sample rate = 250 MSPS, DCS enabled, 1.75 V p-p differential input, VIN = −1.0 dBFS, 32k sample, TA = 25°C, unless otherwise noted. 120 0 170MSPS 90.1MHz @ –1dBFS SNR = 70.8dB (71.8dBFS) SFDR = 88dBc SFDR (dBFS) 100 SNR/SFDR (dBc AND dBFS) –20 –60 –80 SECOND HARMONIC THIRD HARMONIC –100 20 30 40 50 60 FREQUENCY (MHz) 70 80 40 SNR (dBc) –90 –80 –70 –60 –50 –40 –30 INPUT AMPLITUDE (dBFS) –20 –10 0 Figure 9. AD9643-170 Single-Tone SNR/SFDR vs. Input Amplitude (AIN) with fIN = 90.1 MHz 100 170MSPS 185.1MHz @ –1dBFS SNR = 69.8dB (70.8dBFS) SFDR = 85dBc SFDR (dBc) 95 SNR/SFDR (dBc AND dBFS) –20 –40 –60 THIRD HARMONIC SECOND HARMONIC –80 –100 –120 90 85 80 75 SNR (dBFS) 70 65 10 20 30 40 50 FREQUENCY (MHz) 60 70 80 60 60 09636-014 0 90 120 150 180 210 240 270 300 FREQUENCY (MHz) 330 360 390 09636-017 AMPLITUDE (dBFS) SFDR (dBc) 0 –100 0 Figure 10. AD9643-170 Single-Tone SNR/SFDR vs. Input Frequency (fIN) Figure 7. AD9643-170 Single-Tone FFT with fIN = 185.1 MHz 0 0 170MSPS 305.1MHz @ –1dBFS SNR = 68.3dB (69.3dBFS) SFDR = 79dBc –20 SFDR/IMD3 (dBc AND dBFS) –20 –40 SECOND HARMONIC –60 THIRD HARMONIC –80 –100 SFDR (dBc) –40 IMD3 (dBc) –60 –80 SFDR (dBFS) –100 –120 IMD3 (dBFS) –140 0 10 20 30 40 50 FREQUENCY (MHz) 60 70 80 Figure 8. AD9643-170 Single-Tone FFT with fIN = 305.1 MHz –120 –90.0 09636-015 AMPLITUDE (dBFS) 60 09636-016 10 09636-013 0 Figure 6. AD9643-170 Single-Tone FFT with fIN = 90.1 MHz –140 SNR (dBFS) 20 –120 –140 80 –78.5 –67.0 –55.5 –44.0 –32.5 INPUT AMPLITUDE (dBFS) –21.0 –7.0 09636-018 AMPLITUDE (dBFS) –40 Figure 11. AD9643-170 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with fIN1 = 89.12, fIN2 = 92.12 MHz, fS = 170 MSPS Rev. A | Page 16 of 36 0 100 –20 95 SNR/SFDR (dBc AND dBFS) SFDR/IMD3 (dBc AND dBFS) AD9643 SFDR (dBc) –40 IMD3 (dBc) –60 –80 SFDR (dBFS) 90 85 SFDR, CHANNEL B SNR, CHANNEL B SFDR, CHANNEL A SNR, CHANNEL A 80 75 –100 –67.0 –55.5 –44.0 –32.5 INPUT AMPLITUDE (dBFS) –21.0 –7.0 70 40 09636-019 –78.5 Figure 12. AD9643-170 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with fIN1 = 184.12, fIN2 = 187.12 MHz, fS = 170 MSPS 50 60 70 80 90 100 110 120 130 140 150 160 170 SAMPLE RATE (MSPS) 09636-022 IMD3 (dBFS) –120 –90.0 Figure 15. AD9643-170 Single-Tone SNR/SFDR vs. Sample Rate (fS) with fIN = 90.1 MHz 6000 0 170MSPS 89.12MHz @ –7dBFS 92.12MHz @ –7dBFS SFDR = 89dBc (96dBFS) –20 1.34LSB rms 16,379 TOTAL HITS 5000 NUMBER OF HITS –60 –80 –100 3000 2000 10 20 30 40 50 60 FREQUENCY (MHz) 70 80 0 09636-020 0 Figure 13. AD9643-170 Two-Tone FFT with fIN1 = 89.12, fIN2 = 92.12 MHz, fS = 170 MSPS Figure 16. AD9643-170 Grounded Input Histogram 0 0 170MSPS 184.12MHz @ –7dBFS 187.12MHz @ –7dBFS SFDR = 84dBc (91dBFS) –20 –40 AMPLITUDE (dBFS) AMPLITUDE (dBFS) 210MSPS 90.1MHz @ –1dBFS SNR = 70.6dB (71.6dBFS) SFDR = 88dBc –20 –40 –60 –80 –100 –120 –60 SECOND HARMONIC –80 THIRD HARMONIC –100 –120 0 10 20 30 40 50 FREQUENCY (MHz) 60 70 80 –140 09636-021 –140 N–5 N–4N–3N–2N–1 N N+1N+2N+3N+4N+5 OUTPUT CODE 09636-023 1000 –120 –140 4000 Figure 14. AD9643-170 Two-Tone FFT with fIN1 = 184.12, fIN2 = 187.12 MHz, fS = 170 MSPS Rev. A | Page 17 of 36 0 10 20 30 40 50 60 70 FREQUENCY (Hz) 80 90 100 Figure 17. AD9643-210 Single-Tone FFT with fIN = 90.1 MHz 09636-024 AMPLITUDE (dBFS) –40 AD9643 100 0 210MSPS 185.1MHz @ –1dBFS SNR = 70.3dB (71.3dBFS) SFDR = 86dBc 95 SFDR (dBc) SNR/SFDR (dBc AND dBFS) –20 –60 SECOND HARMONIC THIRD HARMONIC –80 –100 –120 0 10 20 30 40 50 60 70 FREQUENCY (MHz) 80 90 100 75 SNR (dBFS) 70 60 60 Figure 18. AD9643-210 Single-Tone FFT with fIN = 185.1 MHz 90 120 150 180 210 240 270 300 FREQUENCY (MHz) 330 360 390 Figure 21. AD9643-210 Single-Tone SNR/SFDR vs. Input Frequency (fIN) 0 0 210MSPS 305.1MHz @ –1dBFS SNR = 67.3dB (68.3dBFS) SFDR = 75dBc –20 SFDR/IMD3 (dBc AND dBFS) –20 –40 AMPLITUDE (dBFS) 80 65 09636-025 –140 85 09636-028 AMPLITUDE (dBFS) –40 90 THIRD HARMONIC –60 SECOND HARMONIC –80 –100 SFDR (dBc) –40 IMD3 (dBc) –60 –80 SFDR (dBFS) –120 –100 –140 –120 –90.0 10 20 30 40 50 60 70 FREQUENCY (MHz) 80 90 100 –78.5 –67.0 –55.5 –44.0 –32.5 INPUT AMPLITUDE (dBFS) –21.0 –7.0 09636-029 0 09636-026 IMD3 (dBFS) Figure 22. AD9643-210 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with fIN1 = 89.12, fIN2 = 92.12 MHz, fS = 210 MSPS Figure 19. AD9643-210 Single-Tone FFT with fIN = 305.1 MHz 120 0 SFDR (dBFS) –20 80 SFDR/IMD3 (dBc AND dBFS) SNR (dBFS) 60 SFDR (dBc) 40 SNR (dBc) 20 –40 IMD3 (dBc) –60 –80 SFDR (dBFS) –100 –90 –80 –70 –60 –50 –40 –30 INPUT AMPLITUDE (dBFS) –20 –10 0 –120 –90.0 09636-027 0 –100 SFDR (dBc) Figure 20. AD9643-210 Single-Tone SNR/SFDR vs. Input Amplitude (AIN) with fIN = 90.1 MHz IMD3 (dBFS) –78.5 –67.0 –55.5 –44.0 –32.5 INPUT AMPLITUDE (dBFS) –21.0 –7.0 09636-030 SNR/SFDR (dBc AND dBFS) 100 Figure 23. AD9643-210 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with fIN1 = 184.12, fIN2 = 187.12 MHz, fS = 210 MSPS Rev. A | Page 18 of 36 AD9643 5000 0 210MSPS 89.12MHz @ –7dBFS 92.12MHz @ –7dBFS SFDR = 88dBc (95dBFS) –20 4000 –40 3500 NUMBER OF HITS AMPLITUDE (dBFS) 1.44LSB rms 16,378 TOTAL HITS 4500 –60 –80 –100 3000 2500 2000 1500 1000 –120 10 20 30 40 50 60 70 FREQUENCY (MHz) 80 90 100 0 09636-031 0 Figure 24. AD9643-210 Two-Tone FFT with fIN1 = 89.12, fIN2 = 92.12 MHz, fS = 210 MSPS Figure 27. AD9643-210 Grounded Input Histogram 0 0 210MSPS 184.12MHz @ –7dBFS 187.12MHz @ –7dBFS SFDR = 88dBc (95dBFS) –20 AMPLITUDE (dBFS) –60 –80 –100 –60 THIRD HARMONIC SECOND HARMONIC –80 –100 10 20 30 40 50 60 70 FREQUENCY (MHz) 80 90 100 –140 09636-032 0 Figure 25. AD9643-210 Two-Tone FFT with fIN1 = 184.12, fIN2 = 187.12 MHz, fS = 210 MSPS 0 10 20 30 40 50 60 70 80 FREQUENCY (MHz) 90 100 110 120 09636-035 –120 Figure 28. AD9643-250 Single-Tone FFT with fIN = 90.1 MHz 100 0 95 –20 250MSPS 185.1MHz @ –1dBFS SNR = 70.6dB (71.6dBFS) SFDR = 85dBc AMPLITUDE (dBFS) –40 90 85 SNR, CHANNEL B SFDR, CHANNEL B SNR, CHANNEL A SFDR, CHANNEL A 80 75 THIRD HARMONIC SECOND HARMONIC –80 –100 –120 60 80 100 120 140 160 SAMPLE RATE (MSPS) 180 200 –140 09636-033 70 40 –60 Figure 26. AD9643-210 Single-Tone SNR/SFDR vs. Sample Rate (fS) with fIN = 90.1 MHz 0 10 20 30 40 50 60 70 80 FREQUENCY (MHz) 90 100 110 120 Figure 29. AD9643-250 Single-Tone FFT with fIN = 185.1 MHz Rev. A | Page 19 of 36 09636-036 AMPLITUDE (dBFS) –40 –120 SNR/SFDR (dBc AND dBFS) 250MSPS 90.1MHz @ –1dBFS SNR = 70.6dB (71.6dBFS) SFDR = 88dBc –20 –40 –140 N–5 N–4N–3N–2N–1 N N+1N+2N+3N+4N+5 OUTPUT CODE 09636-034 500 –140 AD9643 0 0 250MSPS 305.1MHz @ –1dBFS SNR = 68.6dB (71.6dBFS) SFDR = 83dBc –20 SFDR/IMD3 (dBc AND dBFS) –20 AMPLITUDE (dBFS) –40 –60 SECOND HARMONIC THIRD HARMONIC –80 –100 SFDR (dBc) –40 IMD3 (dBc) –60 –80 SFDR (dBFS) –120 –100 –140 –120 –90.0 10 20 30 40 50 60 70 80 FREQUENCY (MHz) 90 100 110 120 Figure 30. AD9643-250 Single-Tone FFT with fIN = 305.1 MHz –78.5 –67.0 –55.5 –44.0 –32.5 INPUT AMPLITUDE (dBFS) –21.0 –7.0 09636-040 0 09636-037 IMD3 (dBFS) Figure 33. AD9643-250 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with fIN1 = 89.12, fIN2 = 92.12 MHz, fS = 250 MSPS 120 0 SFDR (dBFS) –20 80 SFDR/IMD3 (dBc AND dBFS) SNR/SFDR (dBc AND dBFS) 100 SNR (dBFS) 60 SFDR (dBc) 40 SNR (dBc) 20 SFDR (dBc) –40 IMD3 (dBc) –60 –80 SFDR (dBFS) –100 –80 –70 –60 –50 –40 –30 INPUT AMPLITUDE (dBFS) –20 –10 0 –120 –90.0 09636-038 –90 100 0 95 –20 –7.0 –40 85 80 75 SNR (dBFS) 70 –60 –80 –100 100 120 140 160 180 200 FREQUENCY (MHz) 220 240 260 –140 09636-039 80 Figure 32. AD9643-250 Single-Tone SNR/SFDR vs. Input Frequency (fIN) 0 10 20 30 40 50 60 70 80 FREQUENCY (MHz) 90 100 110 120 09636-042 –120 65 60 60 –21.0 250MSPS 89.12MHz @ –7dBFS 92.12MHz @ –7dBFS SFDR = 87dBc (94dBFS) SFDR (dBc) 90 –67.0 –55.5 –44.0 –32.5 INPUT AMPLITUDE (dBFS) Figure 34. AD9643-250 Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with fIN1 = 184.12, fIN2 = 187.12 MHz, fS = 250 MSPS AMPLITUDE (dBFS) SNR/SFDR (dBc AND dBFS) Figure 31. AD9643-250 Single-Tone SNR/SFDR vs. Input Amplitude (AIN) with fIN = 185.1 MHz –78.5 09636-041 IMD3 (dBFS) 0 –100 Figure 35. AD9643-250 Two-Tone FFT with fIN1 = 89.12, fIN2 = 92.12 MHz, fS = 250 MSPS Rev. A | Page 20 of 36 AD9643 5000 0 250MSPS 184.12MHz @ –7dBFS 187.12MHz @ –7dBFS SFDR = 87dBc (94dBFS) –20 4500 4000 –40 3500 NUMBER OF HITS AMPLITUDE (dBFS) 1.33LSB rms 16,378 TOTAL HITS –60 –80 –100 3000 2500 2000 1500 1000 –120 10 20 30 40 50 60 70 80 FREQUENCY (MHz) 90 100 110 120 0 09636-043 0 Figure 36. AD9643-250 Two-Tone FFT with fIN1 = 184.12, fIN2 = 187.12 MHz, fS = 250 MSPS 100 SNR/SFDR (dBc AND dBFS) 95 90 85 SNR, CHANNEL B SFDR, CHANNEL B SNR, CHANNEL A SFDR, CHANNEL A 80 70 40 60 80 100 120 140 160 180 SAMPLE RATE (MSPS) 200 220 240 09636-044 75 Figure 37. AD9643-250 Single-Tone SNR/SFDR vs. Sample Rate (fS) with fIN = 90.1 MHz Rev. A | Page 21 of 36 N–5 N–4N–3N–2N–1 N N+1N+2N+3N+4N+5 OUTPUT CODE Figure 38. AD9643-250 Grounded Input Histogram 09636-045 500 –140 AD9643 EQUIVALENT CIRCUITS AVDD 350Ω SCLK OR PDWN 26kΩ 09636-010 09636-006 VIN Figure 39. Equivalent Analog Input Circuit Figure 43. Equivalent SCLK or PDWN Input Circuit AVDD AVDD AVDD AVDD 0.9V 26kΩ CSB OR OEB CLK– 350Ω 09636-007 CLK+ 15kΩ 09636-011 15kΩ Figure 44. Equivalent CSB Input Circuit Figure 40. Equivalent Clock lnput Circuit DRVDD AVDD AVDD V– V+ DATAOUT– DATAOUT+ SYNC V+ V– 0.9V 0.9V Figure 41. Equivalent LVDS Output Circuit Figure 45. Equivalent SYNC Input Circuit DRVDD 350Ω 26kΩ 09636-009 SDIO 09636-012 09636-063 16kΩ Figure 42. Equivalent SDIO Circuit Rev. A | Page 22 of 36 AD9643 THEORY OF OPERATION The AD9643 has two analog input channels and two digital output channels. The intermediate frequency (IF) signal passes through several stages before appearing at the output port(s). The dual ADC design can be used for diversity reception of signals, where the ADCs operate identically on the same carrier but from two separate antennae. The ADCs can also be operated with independent analog inputs. The user can sample frequencies from dc to 300 MHz using appropriate low-pass or band-pass filtering at the ADC inputs with little loss in ADC performance. Operation to 400 MHz analog input is permitted but occurs at the expense of increased ADC noise and distortion. Synchronization capability is provided to allow synchronized timing between multiple devices. Programming and control of the AD9643 are accomplished using a 3-pin, SPI-compatible serial interface. A small resistor in series with each input can help reduce the peak transient current required from the output stage of the driving source. A shunt capacitor can be placed across the inputs to provide dynamic charging currents. This passive network creates a low-pass filter at the ADC input; therefore, the precise values are dependent on the application. In intermediate frequency (IF) undersampling applications, the shunt capacitors should be reduced. In combination with the driving source impedance, the shunt capacitors limit the input bandwidth. Refer to the AN-742 Application Note, Frequency Domain Response of Switched-Capacitor ADCs; the AN-827 Application Note, A Resonant Approach to Interfacing Amplifiers to Switched-Capacitor ADCs; and the Analog Dialogue article, “Transformer-Coupled Front-End for Wideband A/D Converters,” for more information on this subject. BIAS ADC ARCHITECTURE S Each stage of the pipeline, excluding the last, consists of a low resolution flash ADC connected to a switched-capacitor digitalto-analog converter (DAC) and an interstage residue amplifier (MDAC). The MDAC magnifies the difference between the reconstructed DAC output and the flash input for the next stage in the pipeline. One bit of redundancy is used in each stage to facilitate digital correction of flash errors. The last stage simply consists of a flash ADC. The input stage of each channel contains a differential sampling circuit that can be ac- or dc-coupled in differential or singleended modes. The output staging block aligns the data, corrects errors, and passes the data to the output buffers. The output buffers are powered from a separate supply, allowing digital output noise to be separated from the analog core. During power-down, the output buffers go into a high impedance state. ANALOG INPUT CONSIDERATIONS The analog input to the AD9643 is a differential switchedcapacitor circuit that has been designed for optimum performance while processing a differential input signal. The clock signal alternatively switches the input between sample mode and hold mode (see the configuration shown in Figure 46). When the input is switched into sample mode, the signal source must be capable of charging the sampling capacitors and settling within 1/2 clock cycle. CFB VIN+ CPAR1 CPAR2 H S S CS VIN– CPAR1 CPAR2 S S BIAS CFB 09636-050 The AD9643 architecture consists of a dual front-end sampleand-hold circuit, followed by a pipelined switched-capacitor ADC. The quantized outputs from each stage are combined into a final 14-bit result in the digital correction logic. The pipelined architecture permits the first stage to operate on a new input sample and the remaining stages to operate on the preceding samples. Sampling occurs on the rising edge of the clock. S CS Figure 46. Switched-Capacitor Input For best dynamic performance, the source impedances driving VIN+ and VIN− should be matched, and the inputs should be differentially balanced. Input Common Mode The analog inputs of the AD9643 are not internally dc biased. In ac-coupled applications, the user must provide this bias externally. Setting the device so that VCM = 0.5 × AVDD (or 0.9 V) is recommended for optimum performance. An on-board common-mode voltage reference is included in the design and is available from the VCM pin. Using the VCM output to set the input common mode is recommended. Optimum performance is achieved when the common-mode voltage of the analog input is set by the VCM pin voltage (typically 0.5 × AVDD). The VCM pin must be decoupled to ground by a 0.1 μF capacitor, as described in the Applications Information section. This decoupling capacitor should be placed close to the pin to minimize the series resistance and inductance between the part and this capacitor. Differential Input Configurations Optimum performance is achieved while driving the AD9643 in a differential input configuration. For baseband applications, the AD8138, ADA4937-2, ADA4938-2, and ADA4930-2 Rev. A | Page 23 of 36 AD9643 the recommended input configuration (see Figure 50). In this configuration, the input is ac-coupled and the VCM voltage is provided to each input through a 33 Ω resistor. These resistors compensate for losses in the input baluns to provide a 50 Ω impedance to the driver. differential drivers provide excellent performance and a flexible interface to the ADC. The output common-mode voltage of the ADA4930-2 is easily set with the VCM pin of the AD9643 (see Figure 47), and the driver can be configured in a Sallen-Key filter topology to provide band-limiting of the input signal. In the double balun and transformer configurations, the value of the input capacitors and resistors is dependent on the input frequency and source impedance. Based on these parameters, the value of the input resistors and capacitors may need to be adjusted or some components may need to be removed. Table 10 displays recommended values to set the RC network for different input frequency ranges. However, these values are dependent on the input signal and bandwidth and should be used only as a starting guide. Note that the values given in Table 10 are for each R1, R2, C2, and R3 component shown in Figure 48 and Figure 50. 15pF 200Ω 15Ω VIN– AVDD 5pF ADA4930-2 0.1µF ADC 33Ω 15Ω VCM VIN+ 120Ω 200Ω 33Ω 0.1µF 09636-051 15pF Table 10. Example RC Network Figure 47. Differential Input Configuration Using the ADA4930-2 Frequency Range (MHz) 0 to 100 100 to 300 For baseband applications where SNR is a key parameter, differential transformer coupling is the recommended input configuration. An example is shown in Figure 48. To bias the analog input, the VCM voltage can be connected to the center tap of the secondary winding of the transformer. R2 VIN+ R1 49.9Ω C1 ADC R2 R1 0.1µF R3 VCM VIN– 33Ω 0.1µF C2 R2 Series (Ω) 0 0 1µH 165Ω 15pF VPOS AD8376 Figure 48. Differential Transformer-Coupled Configuration 5.1pF 1nF 1µH The signal characteristics must be considered when selecting a transformer. Most RF transformers saturate at frequencies below a few megahertz. Excessive signal power can also cause core saturation, which leads to distortion. 3.9pF 165Ω 1nF R3 R1 R2 VIN+ 33Ω S S P 0.1µF 2.5kΩ║2pF 68nH Figure 49. Differential Input Configuration Using the AD8376 0.1µF 2V p-p AD9643 VCM 301Ω C2 PA R3 Shunt (Ω) 49.9 49.9 1000pF 180nH 220nH NOTES 1. ALL INDUCTORS ARE COILCRAFT® 0603CS COMPONENTS WITH THE EXCEPTION OF THE 1µH CHOKE INDUCTORS (COIL CRAFT 0603LS). 2. FILTER VALUES SHOWN ARE FOR A 20MHz BANDWIDTH FILTER CENTERED AT 140MHz. At input frequencies in the second Nyquist zone and above, the noise performance of most amplifiers is not adequate to achieve the true SNR performance of the AD9643. For applications where SNR is a key parameter, differential double balun coupling is 0.1µF C2 Shunt (pF) 15 8.2 180nH 220nH 1000pF 09636-052 2V p-p C1 Differential (pF) 8.2 3.9 An alternative to using a transformer-coupled input at frequencies in the second Nyquist zone is to use an amplifier with variable gain. The AD8375 or AD8376 digital variable gain amplifier (DVGAs) provides good performance for driving the AD9643. Figure 49 shows an example of the AD8376 driving the AD9643 through a band-pass antialiasing filter. C2 R3 R1 Series (Ω) 33 15 33Ω 0.1µF C1 R1 ADC R2 R3 C2 Figure 50. Differential Double Balun Input Configuration Rev. A | Page 24 of 36 VIN– 33Ω VCM 0.1µF 09636-054 33Ω 90Ω 09636-053 76.8Ω VIN AD9643 VOLTAGE REFERENCE A stable and accurate voltage reference is built into the AD9643. The full-scale input range can be adjusted by varying the reference voltage via SPI. The input span of the ADC tracks reference voltage changes linearly. CLOCK INPUT 25Ω 390pF CLK+ 390pF 1nF CLOCK INPUT CONSIDERATIONS AVDD 09636-057 CLK– SCHOTTKY DIODES: HSMS2822 25Ω For optimum performance, the AD9643 sample clock inputs, CLK+ and CLK−, should be clocked with a differential signal. The signal is typically ac-coupled into the CLK+ and CLK− pins via a transformer or via capacitors. These pins are biased internally (see Figure 51) and require no external bias. If the inputs are floated, the CLK− pin is pulled low to prevent spurious clocking. ADC 390pF Figure 53. Balun-Coupled Differential Clock (Up to 625 MHz) If a low jitter clock source is not available, another option is to ac-couple a differential PECL signal to the sample clock input pins as shown in Figure 54. The AD9510, AD9511, AD9512, AD9513, AD9514, AD9515, AD9516, AD9517, AD9518, AD9520, AD9522, AD9523, AD9524, and ADCLK905/ADCLK907/ ADCLK925 clock drivers offer excellent jitter performance. 0.9V 0.1µF CLOCK INPUT CLK– CLK+ AD95xx 4pF Figure 51. Simplified Equivalent Clock Input Circuit Figure 52 and Figure 53 show two preferable methods for clocking the AD9643 (at clock rates of up to 625 MHz). A low jitter clock source is converted from a single-ended signal to a differential signal using an RF balun or RF transformer. 50Ω CLK– 50kΩ 240Ω 50kΩ 0.1µF 240Ω AD95xx ADC 100Ω 390pF LVDS DRIVER 100Ω 0.1µF CLK– 50kΩ 50kΩ Figure 55. Differential LVDS Sample Clock (Up to 625 MHz) Input Clock Divider The AD9643 contains an input clock divider with the ability to divide the input clock by integer values between 1 and 8. The duty cycle stabilizer (DCS) is enabled by default on power-up. The AD9643 clock divider can be synchronized using the external SYNC input. Bit 1 and Bit 2 of Register 0x3A allow the clock divider to be resynchronized on every SYNC signal or only on the first SYNC signal after the register is written. A valid SYNC causes the clock divider to reset to its initial state. This synchronization feature allows multiple parts to have their clock dividers aligned to guarantee simultaneous input sampling. 09636-056 CLK– CLOCK INPUT ADC CLK+ 0.1µF CLK+ SCHOTTKY DIODES: HSMS2822 0.1µF CLOCK INPUT The RF balun configuration is recommended for clock frequencies between 125 MHz and 625 MHz, and the RF transformer is recommended for clock frequencies from 10 MHz to 200 MHz. The back-to-back Schottky diodes across the transformer secondary limit clock excursions into the AD9643 to approximately 0.8 V p-p differential. This limit helps prevent the large voltage swings of the clock from feeding through to other portions of the AD9643 while preserving the fast rise and fall times of the signal, which are critical to low jitter performance. 390pF 100Ω 0.1µF A third option is to ac-couple a differential LVDS signal to the sample clock input pins, as shown in Figure 55. The AD9510, AD9511, AD9512, AD9513, AD9514, AD9515, AD9516, AD9517, AD9518, AD9520, AD9522, AD9523, and AD9524 clock drivers offer excellent jitter performance. The AD9643 has a very flexible clock input structure. Clock input can be a CMOS, LVDS, LVPECL, or sine wave signal. Regardless of the type of signal being used, clock source jitter is of the most concern, as described in the Jitter Considerations section. CLOCK INPUT PECL DRIVER Figure 54. Differential PECL Sample Clock (Up to 625 MHz) Clock Input Options Mini-Circuits® ADT1-1WT, 1:1Z 390pF XFMR 0.1µF 09636-058 CLOCK INPUT 09636-055 4pF ADC 0.1µF 09636-059 CLK+ Figure 52. Transformer-Coupled Differential Clock (Up to 200 MHz) Rev. A | Page 25 of 36 AD9643 Jitter on the rising edge of the input clock is still of paramount concern and is not reduced by the duty cycle stabilizer. The duty cycle control loop does not function for clock rates less than 40 MHz nominally. The loop has a time constant associated with it that must be considered when the clock rate can change dynamically. A wait time of 1.5 μs to 5 μs is required after a dynamic clock frequency increase or decrease before the DCS loop is relocked to the input signal. During the time period that the loop is not locked, the DCS loop is bypassed, and internal device timing is dependent on the duty cycle of the input clock signal. In such applications, it may be appropriate to disable the duty cycle stabilizer. In all other applications, enabling the DCS circuit is recommended to maximize ac performance. Jitter Considerations Refer to the AN-501 Application Note, Aperture Uncertainty and ADC System Performance, and the AN-756 Application Note, Sampled Systems and the Effects of Clock Phase Noise and Jitter, for more information about jitter performance as it relates to ADCs. POWER DISSIPATION AND STANDBY MODE As shown in Figure 57, the power dissipated by the AD9643 is proportional to its sample rate. The data in Figure 57 was taken using the same operating conditions as those used for the Typical Performance Characteristics section. 0.8 0.4 0.6 75 65 60 0.05ps 0.2ps 0.5ps 1ps 1.5ps MEASURED 55 50 1 0.3 IAVDD 0.4 0.2 0.3 IDRVDD 0.1 0.1 0 40 0 60 80 100 120 140 160 180 200 ENCODE FREQUENCY (MSPS) 220 240 Figure 57. AD9643-250 Power and Current vs. Sample Rate By asserting PDWN (either through the SPI port or by asserting the PDWN pin high), the AD9643 is placed in power-down mode. In this state, the ADC typically dissipates 10 mW. During power-down, the output drivers are placed in a high impedance state. Asserting the PDWN pin low returns the AD9643 to its normal operating mode. Note that PDWN is referenced to the digital output driver supply (DRVDD) and should not exceed that supply voltage. Low power dissipation in power-down mode is achieved by shutting down the reference, reference buffer, biasing networks, and clock. Internal capacitors are discharged when entering power-down mode and then must be recharged when returning to normal operation. As a result, wake-up time is related to the time spent in power-down mode, and shorter power-down cycles result in proportionally shorter wake-up times. 10 100 INPUT FREQUENCY (MHz) 1000 09636-060 SNR (dBc) 70 0.5 0.2 SNRHF = −10 log[(2π × fIN × tJRMS)2 + 10 ( − SNR LF /10 ) ] 80 TOTAL POWER 0.7 High speed, high resolution ADCs are sensitive to the quality of the clock input. The degradation in SNR at a given input frequency (fIN) due to jitter (tJ) can be calculated by In the equation, the rms aperture jitter represents the rootmean-square of all jitter sources, which include the clock input, the analog input signal, and the ADC aperture jitter specification. IF undersampling applications are particularly sensitive to jitter, as shown in Figure 56. 0.5 SUPPLY CURRENT (A) The AD9643 contains a duty cycle stabilizer (DCS) that retimes the nonsampling (falling) edge, providing an internal clock signal with a nominal 50% duty cycle. This allows the user to provide a wide range of clock input duty cycles without affecting the performance of the AD9643. 09636-061 Typical high speed ADCs use both clock edges to generate a variety of internal timing signals and, as a result, may be sensitive to clock duty cycle. Commonly, a ±5% tolerance is required on the clock duty cycle to maintain dynamic performance characteristics. Power supplies for clock drivers should be separated from the ADC output driver supplies to avoid modulating the clock signal with digital noise. Low jitter, crystal controlled oscillators make the best clock sources. If the clock is generated from another type of source (by gating, dividing, or another method), it should be retimed by the original clock at the last step. TOTAL POWER (W) Clock Duty Cycle Figure 56. AD9643-250 SNR vs. Input Frequency and Jitter The clock input should be treated as an analog signal in cases where aperture jitter may affect the dynamic range of the AD9643. When using the SPI port interface, the user can place the ADC in power-down mode or standby mode. Standby mode allows the user to keep the internal reference circuitry powered when faster wake-up times are required. See the Memory Map Register Description section and the AN-877 Application Note, Interfacing to High Speed ADCs via SPI, for additional details. Rev. A | Page 26 of 36 AD9643 DIGITAL OUTPUTS The AD9643 output drivers can be configured for either ANSI LVDS or reduced drive LVDS using a 1.8 V DRVDD supply. As detailed in the AN-877 Application Note, Interfacing to High Speed ADCs via SPI, the data format can be selected for offset binary, twos complement, or gray code when using the SPI control. Digital Output Enable Function (OEB) The AD9643 has a flexible three-state ability for the digital output pins. The three-state mode is enabled using the OEB pin or through the SPI interface. If the OEB pin is low, the output data drivers are enabled. If the OEB pin is high, the output data drivers are placed in a high impedance state. This OEB function is not intended for rapid access to the data bus. Note that OEB is referenced to the digital output driver supply (DRVDD) and should not exceed that supply voltage. When using the SPI interface, the data outputs of each channel can be independently three-stated by using the output enable bar bit (Bit 4) in Register 0x14. Because the output data is interleaved, if only one of the two channels is disabled, the output data of the remaining channel is repeated in both the rising and falling output clock cycles. Timing The AD9643 provides latched data with a pipeline delay of 10 input sample clock cycles. Data outputs are available one propagation delay (tPD) after the rising edge of the clock signal. The length of the output data lines and loads placed on them should be minimized to reduce transients within the AD9643. These transients can degrade converter dynamic performance. The lowest typical conversion rate of the AD9643 is 40 MSPS. At clock rates below 40 MSPS, dynamic performance may degrade. Data Clock Output (DCO) The AD9643 also provides data clock output (DCO) intended for capturing the data in an external register. Figure 2 shows a graphical timing diagram of the AD9643 output modes. Table 11. Output Data Format Input (V) VIN+ − VIN− VIN+ − VIN− VIN+ − VIN− VIN+ − VIN− VIN+ − VIN− VIN+ − VIN−, Input Span = 1.75 V p-p (V) <–0.875 –0.875 0 +0.875 >+0.875 Offset Binary Output Mode 00 0000 0000 0000 00 0000 0000 0000 10 0000 0000 0000 11 1111 1111 1111 11 1111 1111 1111 Rev. A | Page 27 of 36 Twos Complement Mode (Default) 10 0000 0000 0000 10 0000 0000 0000 00 0000 0000 0000 01 1111 1111 1111 01 1111 1111 1111 OR 1 0 0 0 1 AD9643 CHANNEL/CHIP SYNCHRONIZATION The AD9643 has a SYNC input that allows the user flexible synchronization options for synchronizing the internal blocks. The SYNC feature is useful for guaranteeing synchronized operation across multiple ADCs. The input clock divider can be synchronized using the SYNC input. The divider can be enabled to synchronize on a single occurrence of the SYNC signal or on every occurrence by setting the appropriate bits in Register 0x3A. The SYNC input is internally synchronized to the sample clock. However, to ensure that there is no timing uncertainty between multiple parts, the SYNC input signal should be synchronized to the input clock signal. The SYNC input should be driven using a single-ended CMOS type signal. Using Bit 1 in Register 0x59, the SYNC input can be set to either level or edge sensitive mode. If the SYNC input is set to edge sensitive mode, Bit 0 of Register 0x59 can be used to determine whether the rising or falling edge is used. Rev. A | Page 28 of 36 AD9643 SERIAL PORT INTERFACE (SPI) The AD9643 serial port interface (SPI) allows the user to configure the converter for specific functions or operations through a structured register space provided inside the ADC. The SPI gives the user added flexibility and customization, depending on the application. Addresses are accessed via the serial port and can be written to or read from via the port. Memory is organized into bytes that can be further divided into fields. These fields are documented in the Memory Map section. For detailed operational information, see the AN-877 Application Note, Interfacing to High Speed ADCs via SPI. CONFIGURATION USING THE SPI Three pins define the SPI of this ADC: the SCLK pin, the SDIO pin, and the CSB pin (see Table 12). The SCLK (serial clock) pin is used to synchronize the read and write data presented from/to the ADC. The SDIO (serial data input/output) pin is a dual-purpose pin that allows data to be sent and read from the internal ADC memory map registers. The CSB (chip select bar) pin is an active low control that enables or disables the read and write cycles. Table 12. Serial Port Interface Pins Pin SCLK SDIO CSB Function Serial Clock. The serial shift clock input, which is used to synchronize serial interface reads and writes. Serial Data Input/Output. A dual-purpose pin that typically serves as an input or an output, depending on the instruction being sent and the relative position in the timing frame. Chip Select Bar. An active low control that gates the read and write cycles. The falling edge of CSB, in conjunction with the rising edge of SCLK, determines the start of the framing. An example of the serial timing and its definitions can be found in Figure 58 and Table 5. Other modes involving the CSB are available. The CSB can be held low indefinitely, which permanently enables the device; this is called streaming. The CSB can stall high between bytes to allow for additional external timing. When CSB is tied high, SPI functions are placed in a high impedance mode. This mode turns on any SPI pin secondary functions. All data is composed of 8-bit words. The first bit of each individual byte of serial data indicates whether a read or write command is issued. This allows the serial data input/output (SDIO) pin to change direction from an input to an output. In addition to word length, the instruction phase determines whether the serial frame is a read or write operation, allowing the serial port to be used both to program the chip and to read the contents of the on-chip memory. If the instruction is a readback operation, performing a readback causes the serial data input/ output (SDIO) pin to change direction from an input to an output at the appropriate point in the serial frame. Data can be sent in MSB first mode or in LSB first mode. MSB first is the default on power-up and can be changed via the SPI port configuration register. For more information about this and other features, see the AN-877 Application Note, Interfacing to High Speed ADCs via SPI. HARDWARE INTERFACE The pins described in Table 12 comprise the physical interface between the user programming device and the serial port of the AD9643. The SCLK pin and the CSB pin function as inputs when using the SPI interface. The SDIO pin is bidirectional, functioning as an input during write phases and as an output during readback. The SPI interface is flexible enough to be controlled by either FPGAs or microcontrollers. One method for SPI configuration is described in detail in the AN-812 Application Note, Microcontroller-Based Serial Port Interface (SPI) Boot Circuit. The SPI port should not be active during periods when the full dynamic performance of the converter is required. Because the SCLK signal, the CSB signal, and the SDIO signal are typically asynchronous to the ADC clock, noise from these signals can degrade converter performance. If the on-board SPI bus is used for other devices, it may be necessary to provide buffers between this bus and the AD9643 to prevent these signals from transitioning at the converter inputs during critical sampling periods. During an instruction phase, a 16-bit instruction is transmitted. Data follows the instruction phase, and its length is determined by the W0 and the W1 bits. Rev. A | Page 29 of 36 AD9643 SPI ACCESSIBLE FEATURES Table 13 provides a brief description of the general features that are accessible via the SPI. These features are described in detail in the AN-877 Application Note, Interfacing to High Speed ADCs via SPI. The AD9643 part-specific features are described in the Memory Map Register Description section. Table 13. Features Accessible Using the SPI Feature Name Mode Clock Offset Test I/O Output Mode Output Phase Output Delay VREF Description Allows the user to set either power-down mode or standby mode Allows the user to access the DCS via the SPI Allows the user to digitally adjust the converter offset Allows the user to set test modes to have known data on output bits Allows the user to set up outputs Allows the user to set the output clock polarity Allows the user to vary the DCO delay Allows the user to set the reference voltage tHIGH tDS tS tDH tCLK tH tLOW CSB SDIO DON’T CARE DON’T CARE R/W W1 W0 A12 A11 A10 A9 A8 A7 D5 Figure 58. Serial Port Interface Timing Diagram Rev. A | Page 30 of 36 D4 D3 D2 D1 D0 DON’T CARE 09636-062 SCLK DON’T CARE AD9643 MEMORY MAP READING THE MEMORY MAP REGISTER TABLE Logic Levels Each row in the memory map register table has eight bit locations. The memory map is roughly divided into three sections: the chip configuration registers (Address 0x00 to Address 0x02); the channel index and transfer registers (Address 0x05 and Address 0xFF); and the ADC functions registers, including setup, control, and test (Address 0x08 to Address 0x59). An explanation of logic level terminology follows: The memory map register table (see Table 14) documents the default hexadecimal value for each hexadecimal address shown. The column with the heading Bit 7 (MSB) is the start of the default hexadecimal value given. For example, Address 0x14, the output mode register, has a hexadecimal default value of 0x05. This means that Bit 0 = 1 and Bit 2 = 1, and the remaining bits are 0s. This setting is the default output format value, which is twos complement. For more information on this function and others, see the AN-877 Application Note, Interfacing to High Speed ADCs via SPI. This document details the functions controlled by Register 0x00 to Register 0x25. The remaining registers, Register 0x3A and Register 0x59, are documented in the Memory Map Register Description section. Open and Reserved Locations All address and bit locations that are not included in Table 14 are not currently supported for this device. Unused bits of a valid address location should be written with 0s. Writing to these locations is required only when part of an address location is open (for example, Address 0x18). If the entire address location is open (for example, Address 0x13), this address location should not be written. Default Values • • “Bit is set” is synonymous with “bit is set to Logic 1” or “writing Logic 1 for the bit.” “Clear a bit” is synonymous with “bit is set to Logic 0” or “writing Logic 0 for the bit.” Transfer Register Map Address 0x08 to Address 0x20, Address 0x3A, and Address 0x59 are shadowed. Writes to these addresses do not affect part operation until a transfer command is issued by writing 0x01 to Address 0xFF, setting the transfer bit. This allows these registers to be updated internally and simultaneously when the transfer bit is set. The internal update takes place when the transfer bit is set, and then the bit autoclears. Channel-Specific Registers Some channel setup functions, such as the signal monitor thresholds, can be programmed to a different value for each channel. In these cases, channel address locations are internally duplicated for each channel. These registers and bits are designated in Table 14 as local. These local registers and bits can be accessed by setting the appropriate Channel A or Channel B bits in Register 0x05. If both bits are set, the subsequent write affects the registers of both channels. In a read cycle, only Channel A or Channel B should be set to read one of the two registers. If both bits are set during an SPI read cycle, the part returns the value for Channel A. Registers and bits designated as global in Table 14 affect the entire part and the channel features for which independent settings are not allowed between channels. The settings in Register 0x05 do not affect the global registers and bits. After the AD9643 is reset, critical registers are loaded with default values. The default values for the registers are given in the memory map register table, Table 14. Rev. A | Page 31 of 36 AD9643 MEMORY MAP REGISTER TABLE All address and bit locations that are not included in Table 14 are not currently supported for this device. Table 14. Memory Map Registers Addr Register Bit 7 (Hex) Name (MSB) Chip Configuration Registers 0x00 0 SPI port configuration (global) 1 0x01 Chip ID (global) 0x02 Chip grade (global) Open Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (LSB) LSB first Soft reset 1 1 Soft reset LSB first 0 Open 8-bit chip ID[7:0] (AD9643 = 0x82) (default) Open Speed grade ID 00 = 250 MSPS Default Value (Hex) Default Notes/ Comments 0x18 The nibbles are mirrored so that LSB first mode or MSB first mode registers correctly, regardless of shift mode. Read only. 0x82 Open Open Open Speed grade ID used to differentiate devices; read only. Channel Index and Transfer Registers 0x05 Channel index Open (global) Open Open Open Open Open ADC B (default) ADC A (default) 0x03 0xFF Open Open Open Open Open Open Open Transfer 0x00 ADC Functions 0x08 Power modes (local) Open Open Open Open Open Internal power-down mode (local) 00 = normal operation 01 = full power-down 10 = standby 11 = reserved 0x00 0x09 Global clock (global) Open Open External powerdown pin function (local) 0 = powerdown 1 = standby Open Open Open Open Open 0x01 0x0B Clock divide (global) Open Open Transfer (global) Input clock divider phase adjust 000 = no delay 001 = 1 input clock cycle 010 = 2 input clock cycles 011 = 3 input clock cycles 100 = 4 input clock cycles 101 = 5 input clock cycles 110 = 6 input clock cycles 111 = 7 input clock cycles Rev. A | Page 32 of 36 Clock divide ratio 000 = divide by 1 001 = divide by 2 010 = divide by 3 011 = divide by 4 100 = divide by 5 101 = divide by 6 110 = divide by 7 111 = divide by 8 Duty cycle stabilizer (default) 0x00 Bits are set to determine which device on the chip receives the next write command; applies to local registers only. Synchronously transfers data from the master shift register to the slave. Determines various generic modes of chip operation. Clock divide values other than 000 automatically cause the duty cycle stabilizer to become active. AD9643 Addr (Hex) 0x0D Register Name Test mode (local) Bit 7 (MSB) User test mode control 0 = continuous/ repeat pattern 1 = single pattern, then 0s 0x0E BIST enable (local) Offset adjust (local) Output mode 0x10 0x14 Bit 6 Open Bit 5 Reset PN long gen Open Open Open Open Open Open Open Open 0x15 Output Adjust (Global) Open Open Open 0x16 Clock phase control (global) DCO output delay (global) Invert DCO clock Open Open Enable DCO clock delay Open Open 0x18 Input Span select (global) Open Open Open 0x19 User Test Pattern 1 LSB (global) User Test Pattern 1 MSB (global) User Test Pattern 2 LSB (global) User Test Pattern 2 MSB (global) User Test Pattern 3 LSB (global) User Test Pattern 3 MSB (global) 0x17 0x1A 0x1B 0x1C 0x1D 0x1E Bit 4 Reset PN short gen Bit 3 Bit 0 (LSB) Bit 2 Bit 1 Output test mode 0000 = off (default) 0001 = midscale short 0010 = positive FS 0011 = negative FS 0100 = alternating checkerboard 0101 = PN long sequence 0110 = PN short sequence 0111 = one/zero word toggle 1000 = user test mode 1001 to 1110 = unused 1111 = ramp output Open Open Open BIST enable Reset BIST sequence Offset adjust in LSBs from +31 to −32 (twos complement format) Open Output format Output Output enable bar invert (local) 00 = offset binary (local) 1 = normal 01 = twos complement (default) (default) 0 = inverted 10 = gray code 11 = reserved (local) Open LVDS output drive current adjust 0000 = 3.72 mA output drive current 0001 = 3.5 mA output drive current (default) 0010 = 3.30 mA output drive current 0011 = 2.96 mA output drive current 0100 = 2.82 mA output drive current 0101 = 2.57 mA output drive current 0110 = 2.27 mA output drive current 0111 = 2.0 mA output drive current (reduced range) 1000 to 1111 = reserved Open Open Open Open Open Default Value (Hex) 0x00 0x00 0x00 0x05 Configures the outputs and the format of the data. 0x01 0x00 DCO clock delay [delay = (3100 ps × register value/31 +100)] 00000 = 100 ps 00001 = 200 ps 00010 = 300 ps … 11110 = 3100 ps 11111 = 3200 ps Full-scale input voltage selection 01111 = 2.087 V p-p … 00001 = 1.772 V p-p 00000 = 1.75 V p-p (default) 11111 = 1.727 V p-p … 10000 = 1.383 V p-p User Test Pattern 1[7:0] 0x00 User Test Pattern 1[15:8] 0x00 User Test Pattern 2[7:0] 0x00 User Test Pattern 2[15:8] 0x00 User Test Pattern 3[7:0] 0x00 User Test Pattern 3[15:8] 0x00 Rev. A | Page 33 of 36 Default Notes/ Comments When this register is set, the test data is placed on the output pins in place of normal data. 0x00 0x00 Full-scale input adjustment in 0.022 V steps. AD9643 Addr (Hex) 0x1F 0x20 0x24 0x25 0x3A 0x59 1 Register Name User Test Pattern 4 LSB (global) User Test Pattern 4 MSB (global) BIST signature LSB (local) BIST signature MSB (local) Sync control (global) SYNC pin control (local) Bit 7 (MSB) Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 User Test Pattern 4[7:0] Bit 1 Bit 0 (LSB) Default Value (Hex) 0x00 Default Notes/ Comments User Test Pattern 4[15:8] 0x00 BIST signature[7:0] 0x00 Read only. BIST signature[15:8] 0x00 Read only. Open Open Open Open Open Open Open Open Open Open Clock divider next sync only Open Clock divider sync enable SYNC pin sensitivity 0 = sync on high level 1 = sync on edge Master sync buffer enable 0x00 SYNC pin edge sensitivity 0 = sync on falling edge 1 = sync on rising edge 0x00 The channel index register at Address 0x05 should be set to 0x03 (default) when writing to Address 0x00. MEMORY MAP REGISTER DESCRIPTION Bit 0—Master Sync Buffer Enable For more information on functions controlled in Register 0x00 to Register 0x25, see the AN-877 Application Note, Interfacing to High Speed ADCs via SPI. Bit 0 must be set high to enable any of the sync functions. If the sync capability is not used, this bit should remain low to conserve power. Sync Control (Register 0x3A) Bits[7:3]—Reserved SYNC Pin Control (Register 0x59) Bits [7:2]—Reserved Bit 2—Clock Divider Next Sync Only Bit 1—SYNC Pin Sensitivity If the master sync buffer enable bit (Address 0x3A, Bit 0) and the clock divider sync enable bit (Address 0x3A, Bit 1) are high, Bit 2 allows the clock divider to sync to the first sync pulse that it receives and to ignore the rest. The clock divider sync enable bit (Address 0x3A, Bit 1) resets after it syncs. If Bit 1 is set to 0, the SYNC input responds to a level. If this bit is set low, the SYNC input responds to the edge (rising or falling) set in Bit 0 of Address 0x59. Bit 1—Clock Divider Sync Enable Bit 1 gates the sync pulse to the clock divider. The sync signal is enabled when Bit 1 is high and Bit 0 is high. This is continuous sync mode. Bit 0—SYNC Pin Edge Sensitivity If Bit 1 is set high, setting Bit 0 to a 0 causes the SYNC input to respond to a falling edge. If this bit is set, the SYNC input respond to a rising edge. Rev. A | Page 34 of 36 AD9643 APPLICATIONS INFORMATION DESIGN GUIDELINES VCM Before starting system level design and layout of the AD9643, it is recommended that the designer become familiar with these guidelines, which discuss the special circuit connections and layout requirements needed for certain pins. The VCM pin should be decoupled to ground with a 0.1 μF capacitor, as shown in Figure 48. For optimal channel-to-channel isolation, a 33 Ω resistor should be included between the AD9643 VCM pin and the Channel A analog input network connection, as well as between the AD9643 VCM pin and the Channel B analog input network connection. Power and Ground Recommendations When connecting power to the AD9643, it is recommended that two separate 1.8 V supplies be used: one supply should be used for analog (AVDD), and a separate supply should be used for the digital outputs (DRVDD). The designer can employ several different decoupling capacitors to cover both high and low frequencies. These capacitors should be located close to the point of entry at the PC board level and close to the pins of the part with minimal trace length. A single PCB ground plane should be sufficient when using the AD9643. With proper decoupling and smart partitioning of the PCB analog, digital, and clock sections, optimum performance is easily achieved. SPI Port The SPI port should not be active during periods when the full dynamic performance of the converter is required. Because the SCLK, CSB, and SDIO signals are typically asynchronous to the ADC clock, noise from these signals can degrade converter performance. If the on-board SPI bus is used for other devices, it may be necessary to provide buffers between this bus and the AD9643 to keep these signals from transitioning at the converter input pins during critical sampling periods. Exposed Paddle Thermal Heat Slug Recommendations It is mandatory that the exposed paddle on the underside of the ADC be connected to analog ground (AGND) to achieve the best electrical and thermal performance. A continuous, exposed (no solder mask) copper plane on the PCB should mate to the AD9643 exposed paddle, Pin 0. The copper plane should have several vias to achieve the lowest possible resistive thermal path for heat dissipation to flow through the bottom of the PCB. These vias should be filled or plugged with nonconductive epoxy. To maximize the coverage and adhesion between the ADC and the PCB, a silkscreen should be overlaid to partition the continuous plane on the PCB into several uniform sections. This provides several tie points between the ADC and the PCB during the reflow process. Using one continuous plane with no partitions guarantees only one tie point between the ADC and the PCB. See the evaluation board for a PCB layout example. For detailed information about the packaging and PCB layout of chip scale packages, refer to the AN-772 Application Note, A Design and Manufacturing Guide for the Lead Frame Chip Scale Package (LFCSP). Rev. A | Page 35 of 36 AD9643 OUTLINE DIMENSIONS 0.60 MAX 9.00 BSC SQ 0.60 MAX 64 49 48 PIN 1 INDICATOR 1 PIN 1 INDICATOR 8.75 BSC SQ 0.50 BSC 0.50 0.40 0.30 1.00 0.85 0.80 33 32 16 17 0.25 MIN 7.50 REF 0.80 MAX 0.65 TYP 12° MAX 0.05 MAX 0.02 NOM SEATING PLANE 0.30 0.23 0.18 6.35 6.20 SQ 6.05 EXPOSED PAD (BOTTOM VIEW) 0.20 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-VMMD-4 091707-C TOP VIEW Figure 59. 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 9 mm × 9 mm Body, Very Thin Quad (CP-64-4) Dimensions shown in millimeters ORDERING GUIDE Model1 AD9643BCPZ-170 AD9643BCPZ-210 AD9643BCPZ-250 AD9643BCPZRL7-170 AD9643BCPZRL7-210 AD9643BCPZRL7-250 AD9643-170EBZ AD9643-210EBZ AD9643-250EBZ 1 Temperature Range −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C Package Description 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ] 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ] Evaluation Board with AD9643-170 Evaluation Board with AD9643-210 Evaluation Board with AD9643-250 Z = RoHS Compliant Part. ©2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D09636-0-5/11(A) Rev. A | Page 36 of 36 Package Option CP-64-4 CP-64-4 CP-64-4 CP-64-4 CP-64-4 CP-64-4