AD7951 Analog Devices, AD7951 Datasheet - Page 9

• Manufacturer Part Number: AD7951
• Manufacturer: Analog Devices

Specifications of AD7951

• Resolution (bits): 14bit
• # Chan: 1
• Sample Rate: 1MSPS
• Interface: Byte,Par,Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni
• Ain Range: Bip 10V,Bip 5.0V,Uni 10V,Uni 5.0V
• Adc Architecture: SAR
• Pkg Type: CSP,QFP

Pin No.
13
14
15
16
17
18
19
20
21
22
23
Mnemonic
D2 or
EXT/INT
D3 or
INVSYNC
D4 or
INVSCLK
D5 or
RDC or
SDIN
OGND
OVDD
DVDD
DGND
D6 or
SDOUT
D7 or
SDCLK
D8 or
SYNC
Type
DI/O
DI/O
DI/O
DI/O
P
P
P
P
DO
DI/O
DO
1
Description
In parallel mode, this output is used as Bit 2 of the parallel port data output bus.
Serial Data Clock Source Select. In serial mode, this input is used to select the internally generated
(master) or external (slave) serial data clock for the AD7951 output data.
When EXT/INT = low, master mode; the internal serial data clock is selected on SDCLK output.
When EXT/INT = high, slave mode; the output data is synchronized to an external clock signal (gated
by CS) connected to the SDCLK input.
In parallel mode, this output is used as Bit 3 of the parallel port data output bus.
Serial Data Invert Sync Select. In serial master mode (SER/PAR = high, 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.
In parallel mode, this output is used as Bit 4 of the parallel port data output bus.
In all serial modes, invert SDCLK/SCCLK select. This input is used to invert both SDCLK and SCCLK.
When INVSCLK = low, the rising edge of SDCLK/SCCLK are used.
When INVSCLK = high, the falling edge of SDCLK/SCCLK are used.
In parallel mode, this output is used as Bit 5 of the parallel port data output bus.
Serial Data Read During Convert. In serial master mode (SER/PAR = high, EXT/INT = low) RDC is used to
select the read mode. Refer to the Master Serial Interface section.
When RDC = low, the current result is read after conversion. Note the maximum throughput is not
attainable in this mode.
When RDC = high, the previous conversion result is read during the current conversion.
Serial Data In. In serial slave mode (SER/PAR = high EXT/INT = high) SDIN can 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 SDCLK periods after the initiation of the read sequence.
Input/Output Interface Digital Power Ground. Ground reference point for digital outputs. Should be
connected to the system digital ground ideally at the same potential as AGND and DGND.
Input/Output Interface Digital Power. Nominally at the same supply as the supply of the host interface
2.5 V, 3 V, or 5 V and decoupled with 10 μF and 100 nF capacitors.
Digital Power. Nominally at 4.75 V to 5.25 V and decoupled with 10 μF and 100 nF capacitors. Can be
supplied from AVDD.
Digital Power Ground. Ground reference point for digital outputs. Should be connected to system
digital ground ideally at the same potential as AGND and OGND.
In parallel mode, this output is used as Bit 6 of the parallel port data output bus.
Serial Data output. In all serial modes this pin is used as the serial data output synchronized to SDCLK.
Conversion results are stored in an on-chip register. The AD7951 provides the conversion result, MSB
first, from its internal shift register. The data format is determined by the logic level of OB/2C.
When EXT/INT = low (master mode), SDOUT is valid on both edges of SDCLK.
When EXT/INT = high (slave mode):
When INVSCLK = low, SDOUT is updated on SDCLK rising edge.
When INVSCLK = high, SDOUT is updated on SDCLK falling edge.
In parallel mode, this output is used as Bit 7 of the parallel port data output bus.
Serial Data Clock. In all serial modes, this pin is used as the serial data clock input or output, dependent
on the logic state of the EXT/INT pin. The active edge where the data SDOUT is updated depends on
the logic state of the INVSCLK pin.
In parallel mode, this output is used as Bit 8 of the parallel port data output bus.
Serial Data Frame Synchronization. In serial master mode (SER/PAR = high, 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 the
SDOUT output is valid.
When a read sequence is initiated and INVSYNC = high, SYNC is driven low and remains low while the
SDOUT output is valid.
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AD7951