Datasheet AD7938, AD7939 (Analog Devices) - 6

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AD7938/AD7939 Data Sheet Parameter Value1 Unit Test Conditions/Comments
REFERENCE INPUT/OUTPUT VREF Input Voltage5 2.5 V ±1% for specified performance DC Leakage Current4 ±1 µA max External reference applied to pin VREFOUT Output Voltage 2.5 V ±0.2% max @ 25°C VREFOUT Temperature Coefficient 25 ppm/°C max 5 ppm/°C typ VREF Noise 10 µV typ 0.1 Hz to 10 Hz bandwidth 130 µV typ 0.1 Hz to 1 MHz bandwidth VREF Output Impedance 10 Ω typ VREF Input Capacitance 15 pF typ When in track 25 pF typ When in hold LOGIC INPUTS Input High Voltage, VINH 2.4 V min Input Low Voltage, VINL 0.8 V max Input Current, IIN ±5 µA max Typically 10 nA, VIN = 0 V or VDRIVE Input Capacitance, C 4 IN 10 pF typ LOGIC OUTPUTS Output High Voltage, VOH 2.4 V min ISOURCE = 200 µA Output Low Voltage, VOL 0.4 V max ISINK = 200 µA Floating-State Leakage Current ±3 µA max Floating-State Output Capacitance4 10 pF typ Output Coding Straight (natural) binary CODING bit = 0 Twos complement CODING bit =1 CONVERSION RATE Conversion Time t2 + 13 tCLKIN ns Track-and-Hold Acquisition Time 125 ns max Full-scale step input 80 ns typ Sine wave input Throughput Rate 1.5 MSPS max POWER REQUIREMENTS VDD 2.7/5.25 V min/max VDRIVE 2.7/5.25 V min/max I 6 DD Digital inputs = 0 V or VDRIVE Normal Mode (Static) 0.8 mA typ VDD = 2.7 V to 5.25 V, SCLK on or off Normal Mode (Operational) 2.7 mA max VDD = 4.75 V to 5.25 V 2.0 mA max VDD = 2.7 V to 3.6 V Autostandby Mode 0.3 mA typ fSAMPLE = 100 kSPS, VDD = 5 V 160 µA typ Static Full/Autoshutdown Mode (Static) 2 µA max SCLK on or off Power Dissipation Normal Mode (Operational) 13.5 mW max VDD = 5 V 6 mW max VDD = 3 V Autostandby Mode (Static) 800 µW typ VDD = 5 V 480 µW typ VDD = 3 V Full/Autoshutdown Mode (Static) 10 µW max VDD = 5 V 6 µW max VDD = 3 V 1 Temperature range is −40°C to +85°C. 2 See the Terminology section. 3 For full common-mode range, see Figure 26 and Figure 27. 4 Sample tested during initial release to ensure compliance. 5 This device is operational with an external reference in the range of 0.1 V to VDD. See the Reference section for more details. 6 Measured with a midscale dc analog input. Rev. D | Page 6 of 36 Document Outline FEATURES GENERAL DESCRIPTION PRODUCT HIGHLIGHTS REVISION HISTORY SPECIFICATIONS AD7938 SPECIFICATIONS AD7939 SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY ON-CHIP REGISTERS CONTROL REGISTER SEQUENCER OPERATION Writing to the Control Register to Program the Sequencer SHADOW REGISTER CIRCUIT INFORMATION CONVERTER OPERATION ADC TRANSFER FUNCTION TYPICAL CONNECTION DIAGRAM ANALOG INPUT STRUCTURE ANALOG INPUTS Single-Ended Mode Differential Mode Driving Differential Inputs Using an Op Amp Pair Pseudo Differential Mode ANALOG INPUT SELECTION Traditional Multichannel Operation (SEQ = SHDW = 0) Using the Sequencer: Programmable Sequence (SEQ = 0, SHDW = 1) Consecutive Sequence (SEQ = 1, SHDW = 1) REFERENCE Digital Inputs VDRIVE Input PARALLEL INTERFACE Reading Data from the AD7938/AD7939 Writing Data to the AD7938/AD7939 POWER MODES OF OPERATION Normal Mode (PM1 = PM0 = 0) Autoshutdown (PM1 = 0; PM0 = 1) Autostandby (PM1 = 1; PM0 = 0) Full Shutdown Mode (PM1 =1; PM0 = 1) POWER vs. THROUGHPUT RATE MICROPROCESSOR INTERFACING AD7938/AD7939 to ADSP-21xx Interface AD7938/AD7939 to ADSP-21065L Interface AD7938/AD7939 to TMS32020, TMS320C25, and TMS320C5x Interface AD7938/AD7939 to 80C186 Interface APPLICATION HINTS GROUNDING AND LAYOUT PCB DESIGN GUIDELINES FOR CHIP SCALE PACKAGE EVALUATING AD7938/AD7939 PERFORMANCE OUTLINE DIMENSIONS ORDERING GUIDE