AD9251BCPZRL7 Analog Devices, Inc., AD9251BCPZRL7 Datasheet - Page 29

• Manufacturer Part Number: AD9251BCPZRL7
• Description: 14-bit, 20 Msps/40 Msps/65 Msps/80 Msps, 1.8 V Dual Analog-to-digital Converter
• Manufacturer: Analog Devices, Inc.

Preliminary Technical Data
CONFIGURATION WITHOUT THE SPI
In applications that do not interface to the SPI control registers,
the SDIO/DCS pin, the SCLK/DFS pin, the OE pin, and the
PDWN pin serve as standalone CMOS-compatible control pins.
When the device is powered up, it is assumed that the user
intends to use the pins as static control lines for the duty cycle
stabilizer, output data format, output enable, and power-down
feature control. In this mode, connect the CS chip select to
AVDD, which disables the serial port interface.
Table 14. Mode Selection
Pin
SDIO/DCS
SCLK/DFS
OE
PDWN
SCLK
SDIO
CS
DON’T CARE
DON’T CARE
External
Voltage
AVDD (default)
AGND
AVDD
AGND (default)
AVDD
AGND (default)
AVDD
AGND (default)
t
S
R/W
t
DS
W1
Configuration
Duty cycle stabilizer enabled
Duty cycle stabilizer disabled
Twos complement enabled
Offset binary enabled
Outputs in high impedance
Outputs enabled
Chip in power-down or standby
Normal operation
W0
t
DH
A12
t
HIGH
A11
Figure 50. Serial Port Interface Timing Diagram
t
LOW
A10
Rev. PrH | Page 29 of 36
A9
t
CLK
A8
A7
SPI ACCESSIBLE FEATURES
Table 15 provides a brief description of the general features that
are accessible via the SPI. These features are described in detail
in the AN-877 Application Note, Interfacing to High Speed ADCs
via SPI. The AD9251 part-specific features are described in
detail following the external memory map register table.
Table 15. Features Accessible Using the SPI
Feature Name
Mode
Clock
Offset
Test I/O
Output Mode
Output Phase
Output Delay
VREF
D5
D4
Description
Allows the user to set either power-down mode
or standby mode
Allows the user to access the DCS via the SPI
Allows the user to digitally adjust the
converter offset
Allows the user to set test modes to have
known data on output bits
Allows the user to set up outputs
Allows the user to set the output clock polarity
Allows the user to vary the DCO delay
Allows the user to set the reference voltage
D3
D2
D1
D0
t
H
DON’T CARE
AD9251
DON’T CARE