AD9681Data SheetDIGITAL SPECIFICATIONS AVDD = 1.8 V, DRVDD = 1.8 V, 2 V p-p differential input, 1.0 V internal reference, AIN = −1.0 dBFS, unless otherwise noted. Table 3. Parameter1 TempMinTypMaxUnit CLOCK INPUTS (CLK+, CLK−) Logic Compliance CMOS/LVDS/LVPECL Differential Input Voltage2 Full 0.2 3.6 V p-p Input Voltage Range Full GND − 0.2 AVDD + 0.2 V Input Common-Mode Voltage Full 0.9 V Input Resistance (Differential) 25°C 15 kΩ Input Capacitance 25°C 4 pF LOGIC INPUTS (PDWN, SYNC, SCLK) Logic 1 Voltage Full 1.2 AVDD + 0.2 V Logic 0 Voltage Full 0 0.8 V Input Resistance 25°C 30 kΩ Input Capacitance 25°C 2 pF LOGIC INPUTS (CSB1, CSB2) Logic 1 Voltage Full 1.2 AVDD + 0.2 V Logic 0 Voltage Full 0 0.8 V Input Resistance 25°C 26 kΩ Input Capacitance 25°C 2 pF LOGIC INPUT (SDIO) Logic 1 Voltage Full 1.2 AVDD + 0.2 V Logic 0 Voltage Full 0 0.8 V Input Resistance 25°C 26 kΩ Input Capacitance 25°C 5 pF LOGIC OUTPUT (SDIO)3 Logic 1 Voltage (IOH = 800 μA) Full 1.79 V Logic 0 Voltage (IOL = 50 μA) Full 0.05 V DIGITAL OUTPUTS (D0±xx, D1±xx), ANSI-644 Logic Compliance LVDS Differential Output Voltage (VOD) Full 290 345 400 mV Output Offset Voltage (VOS) Full 1.15 1.25 1.35 V Output Coding (Default) Twos complement DIGITAL OUTPUTS (D0±xx, D1±xx), LOW POWER, REDUCED SIGNAL OPTION Logic Compliance LVDS Differential Output Voltage (VOD) Full 160 200 230 mV Output Offset Voltage (VOS) Full 1.15 1.25 1.35 V Output Coding (Default) Twos complement 1 See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for definitions and for details on how these tests were completed. 2 Specified for LVDS and LVPECL only. 3 Specified for 13 SDIO/OLM pins sharing the same connection. Rev. C | Page 6 of 40 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM PRODUCT HIGHLIGHTS TABLE OF CONTENTS REVISION HISTORY FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS DC SPECIFICATIONS AC SPECIFICATIONS DIGITAL SPECIFICATIONS SWITCHING SPECIFICATIONS TIMING SPECIFICATIONS Timing Diagrams ABSOLUTE MAXIMUM RATINGS THERMAL CHARACTERISTICS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS EQUIVALENT CIRCUITS THEORY OF OPERATION ANALOG INPUT CONSIDERATIONS Input Common Mode Differential Input Configurations VOLTAGE REFERENCE Internal Reference Connection External Reference Operation CLOCK INPUT CONSIDERATIONS Clock Input Options Input Clock Divider Clock Duty Cycle Jitter Considerations POWER DISSIPATION AND POWER-DOWN MODE DIGITAL OUTPUTS AND TIMING SDIO/OLM Pin SCLK/DTP Pin CSB1 and CSB2 Pins RBIAS1 and RBIAS2 Pins OUTPUT TEST MODES SERIAL PORT INTERFACE (SPI) CONFIGURATION USING THE SPI HARDWARE INTERFACE CONFIGURATION WITHOUT THE SPI SPI ACCESSIBLE FEATURES MEMORY MAP READING THE MEMORY MAP REGISTER TABLE Open Locations Default Values Logic Levels Channel Specific Registers MEMORY MAP MEMORY MAP REGISTER DESCRIPTIONS Device Index (Register 0x05) Transfer (Register 0xFF) Power Modes (Register 0x08) Enhancement Control (Register 0x0C) Output Mode (Register 0x14) Output Adjust (Register 0x15) Output Phase (Register 0x16) Serial Output Data Control (Register 0x21) Resolution/Sample Rate Override (Register 0x100) User I/O Control 2 (Register 0x101) User I/O Control 3 (Register 0x102) APPLICATIONS INFORMATION DESIGN GUIDELINES POWER AND GROUND RECOMMENDATIONS BOARD LAYOUT CONSIDERATIONS Sources of Coupling Crosstalk Between Inputs Coupling of Digital Output Switching Noise to Analog Inputs and Clock CLOCK STABILITY CONSIDERATIONS VCM REFERENCE DECOUPLING SPI PORT OUTLINE DIMENSIONS ORDERING GUIDE