Datasheet AD7621 (Analog Devices) - 9

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AD7621 Pin No. Mnemonic Type1 Description
14 D5 DI/O When SER/PAR = low this output is used as Bit 5 of the parallel port data output bus. or INVSYNC When SER/PAR = high, invert sync select. In serial master mode (EXT/INT = low), this input is used to select the active state of the SYNC signal. When INVSYNC = low, SYNC is active high. When INVSYNC = high, SYNC is active low. 15 D6 DI/O When SER/PAR = low this output is used as Bit 6 of the parallel port data output bus. or INVSCLK Invert SCLK Select. In all serial modes, this input is used to invert the SCLK signal. 16 D7 DI/O Bit 7 of the Parallel Port Data Output Bus. or RDC When SER/PAR = high, read during convert. When using Serial Master mode (EXT/INT = low), RDC is used to select the read mode. When RDC = high, the previous conversion result is read during current conversion and the period of SCLK changes (see the Master Serial Interface section). When RDC = low (read after convert), the current result is read after conversion. or SDIN Serial Data In. When using serial slave mode, (EXT/INT = high), SDIN could be used as a data input to daisy-chain the conversion results from two or more ADCs onto a single SDOUT line. The digital data level on SDIN is output on SDOUT with a delay of 16 SCLK periods after the initiation of the read sequence. 17 OGND P Input/Output Interface Digital Power Ground. 18 OVDD P Input/Output Interface Digital Power. Nominally at the same supply as the supply of the host interface (2.5 V or 3 V). 19 DVDD P Digital Power. Nominally at 2.5 V. 20 DGND P Digital Power Ground. 21 D8 DO When SER/PAR = low this output is used as Bit 8 of the parallel port data output bus. or SDOUT When SER/PAR = high, serial data output. In serial mode, this pin is used as the serial data output synchronized to SCLK. Conversion results are stored in an on-chip register. The AD7621 provides the conversion result, MSB first, from its internal shift register. The data format is determined by the logic level of OB/2C. In master mode (EXT/INT = low). SDOUT is valid on both edges of SCLK. In slave mode (EXT/INT = high): When INVSCLK = low, SDOUT is updated on SCLK rising edge and valid on the next falling edge. When INVSCLK = high, SDOUT is updated on SCLK falling edge and valid on the next rising edge. 22 D9 DI/O Parallel Port Data Output Bus Bit 9. When SER/PAR = low, this output is used as Bit 9 of the parallel port data output bus. or SCLK Serial Clock. When SER/PAR = high, serial clock. In all serial modes, this pin is used as the serial data clock input or output, dependent upon the logic state of the EXT/INT pin. The active edge where the data SDOUT is updated depends upon the logic state of the INVSCLK pin. 23 D10 DO When SER/PAR = low, this output is used as Bit 10 of the parallel port data output bus. or SYNC When SER/PAR = high, frame synchronization. In serial master mode (EXT/INT= low), this output is used as a digital output frame synchronization for use with the internal data clock. When a read sequence is initiated and INVSYNC = low, SYNC is driven high and remains high while SDOUT output is valid. When a read sequence is initiated and INVSYNC = high, SYNC is driven low and remains low while SDOUT output is valid. 24 D11 DO Parallel Port Data Output Bus Bit 11. When SER/PAR = low, this output is used as Bit 11 of the parallel port data output bus. or RDERROR Read Error. When SER/PAR = high, read error. In serial slave mode (EXT/INT = high), this output is used as an incomplete read error flag. If a data read is started and not completed when the current conversion is complete, the current data is lost and RDERROR is pulsed high. 25 to 28 D[12:15] DO Bit 12 to Bit 15 of the Parallel Port Data Output Bus. 29 BUSY DO Busy Output. Transitions high when a conversion is started, and remains high until the conversion is complete and the data is latched into the on-chip shift register. The falling edge of BUSY can be used as a data ready clock signal. 30 DGND P Digital Power Ground. 31 RD DI Read Data. When CS and RD are both low, the interface parallel or serial output bus is enabled. Rev. 0 | Page 9 of 32 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM PRODUCT HIGHLIGHTS SPECIFICATIONS TIMING SPECIFICATIONS SERIAL CLOCK TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TERMINOLOGY TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CIRCUIT INFORMATION CONVERTER OPERATION MODES OF OPERATION TRANSFER FUNCTIONS TYPICAL CONNECTION DIAGRAM ANALOG INPUTS DRIVER AMPLIFIER CHOICE Single-to-Differential Driver VOLTAGE REFERENCE INPUT Internal Reference External 1.2 V Reference and Internal Buffer External Reference Reference Decoupling Temperature Sensor POWER SUPPLY Power Sequencing Power-Up POWER DISSIPATION VS. THROUGHPUT CONVERSION CONTROL INTERFACES DIGITAL INTERFACE RESET PARALLEL INTERFACE Master Parallel Interface Slave Parallel Interface 8-Bit Interface (Master or Slave) SERIAL INTERFACE MASTER SERIAL INTERFACE Internal Clock SLAVE SERIAL INTERFACE External Clock External Discontinuous Clock Data Read After Conversion External Clock Data Read During Previous Conversion MICROPROCESSOR INTERFACING SPI Interface (ADSP-219x) APPLICATION LAYOUT EVALUATING THE AD7621 PERFORMANCE OUTLINE DIMENSIONS ORDERING GUIDE