Datasheet AD7172-4 (Analog Devices) - 8

link to page 8 link to page 8
Data Sheet AD7172-4 TIMING CHARACTERISTICS
IOVDD = 2 V to 5.5 V, DGND = 0 V, Input Logic 0 = 0 V, Input Logic 1 = IOVDD, CLOAD = 20 pF, unless otherwise noted.
Table 2. Parameter Limit at TMIN, TMAX Unit Test Conditions/Comments1, 2
SCLK t3 25 ns min SCLK high pulse width t4 25 ns min SCLK low pulse width READ OPERATION t1 0 ns min CS falling edge to DOUT/RDY active time 15 ns max IOVDD = 4.75 V to 5.5 V 40 ns max IOVDD = 2 V to 3.6 V t 3 2 0 ns min SCLK active edge to data valid delay4 12.5 ns max IOVDD = 4.75 V to 5.5 V 25 ns max IOVDD = 2 V to 3.6 V t 5 2.5 ns min Bus relinquish time after CS inactive edge 20 ns max t6 0 ns min SCLK inactive edge to CS inactive edge t 5 7 10 ns min SCLK inactive edge to DOUT/RDY high/low WRITE OPERATION t8 0 ns min CS falling edge to SCLK active edge setup time4 t9 8 ns min Data valid to SCLK edge setup time t10 8 ns min Data valid to SCLK edge hold time t11 5 ns min CS rising edge to SCLK edge hold time 1 Sample tested during initial release to ensure compliance. 2 See Figure 2 and Figure 3. 3 This parameter is defined as the time required for the output to cross the VOL or VOH limits. 4 The SCLK active edge is the falling edge of SCLK. 5 DOUT/RDY returns high after a read of the data register. In single conversion mode and continuous conversion mode, the same data can be read again, if required, while DOUT/RDY is high, although care must be taken to ensure that subsequent reads do not occur close to the next output update. If the continuous read feature is enabled, the digital word can be read only once.
TIMING DIAGRAMS CS (I) t t 6 1 t5 DOUT/RDY (O) MSB LSB t t7 2 t3 SCLK (I)
3
t4
00 6-
I = INPUT, O = OUTPUT
67 12 Figure 2. Read Cycle Timing Diagram
CS (I) t8 t11 SCLK (I) t9 t10 DIN (I) MSB LSB
04 0 76-
I = INPUT, O = OUTPUT
126 Figure 3. Write Cycle Timing Diagram Rev. B | Page 7 of 61 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS TIMING DIAGRAMS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS NOISE PERFORMANCE AND RESOLUTION GETTING STARTED POWER SUPPLIES Recommended Linear Regulators DIGITAL COMMUNICATION Accessing the ADC Register Map AD7172-4 RESET CONFIGURATION OVERVIEW Channel Configuration Channel Registers ADC Setups Setup Configuration Registers Filter Configuration Registers Gain Registers Offset Registers ADC Mode and Interface Mode Configuration ADC Mode Register Interface Mode Register Understanding Configuration Flexibility CIRCUIT DESCRIPTION BUFFERED ANALOG INPUT CROSSPOINT MULTIPLEXER Fully Differential Inputs Single-Ended Inputs AD7172-4 REFERENCE BUFFERED REFERENCE INPUT CLOCK SOURCE Internal Oscillator External Crystal External Clock DIGITAL FILTERS SINC5 + SINC1 FILTER SINC3 FILTER SINGLE CYCLE SETTLING ENHANCED 50 Hz AND 60 Hz REJECTION FILTERS OPERATING MODES CONTINUOUS CONVERSION MODE CONTINUOUS READ MODE SINGLE CONVERSION MODE STANDBY AND POWER-DOWN MODES CALIBRATION DIGITAL INTERFACE CHECKSUM PROTECTION CRC CALCULATION Polynomial Example of a Polynomial CRC Calculation—24-Bit Word: 0x654321 (8-Bit Command and 16-Bit Data) XOR Calculation Example of an XOR Calculation—24-Bit Word: 0x654321 (8-Bit Command and 16-Bit Data) INTEGRATED FUNCTIONS GENERAL-PURPOSE INPUT/OUTPUT EXTERNAL MULTIPLEXER CONTROL DELAY 16-BIT/24-BIT CONVERSIONS DOUT_RESET SYNCHRONIZATION Normal Synchronization Alternate Synchronization ERROR FLAGS ADC_ERROR CRC_ERROR REG_ERROR Input/Output DATA_STAT IOSTRENGTH GROUNDING AND LAYOUT REGISTER SUMMARY REGISTER DETAILS COMMUNICATIONS REGISTER STATUS REGISTER ADC MODE REGISTER INTERFACE MODE REGISTER REGISTER CHECK DATA REGISTER GPIO CONFIGURATION REGISTER ID REGISTER CHANNEL REGISTER 0 CHANNEL REGISTER 1 TO CHANNEL REGISTER 7 SETUP CONFIGURATION REGISTER 0 SETUP CONFIGURATION REGISTER 1 TO SETUP CONFIGURATION REGISTER 7 FILTER CONFIGURATION REGISTER 0 FILTER CONFIGURATION REGISTER 1 TO FILTER CONFIGURATION REGISTER 7 OFFSET REGISTER 0 OFFSET REGISTER 1 TO OFFSET REGISTER 7 GAIN REGISTER 0 GAIN REGISTER 1 TO GAIN REGISTER 7 OUTLINE DIMENSIONS ORDERING GUIDE