AD9643 Analog Devices, AD9643 Datasheet - Page 31

• Manufacturer Part Number: AD9643
• Description: 14-Bit, 170/210/250 MSPS, 1.8 V Dual Analog-to-Digital Converter (ADC)
• Manufacturer: Analog Devices

Specifications of AD9643

• Resolution (bits): 14bit
• # Chan: 2
• Sample Rate: 250MSPS
• Interface: LVDS,Par
• Analog Input Type: Diff-Bip
• Ain Range: 1.75 V p-p
• Adc Architecture: Pipelined
• Pkg Type: CSP

Data Sheet
MEMORY MAP
READING THE MEMORY MAP REGISTER TABLE
Each row in the memory map register table has eight bit locations.
The memory map is roughly divided into three sections: the chip
configuration registers (Address 0x00 to Address 0x02); the
channel index and transfer registers (Address 0x05 and
Address 0xFF); and the ADC functions registers, including setup,
control, and test (Address 0x08 to Address 0x3A).
The memory map register table (see Table 14) documents the
default hexadecimal value for each hexadecimal address shown.
The column with the heading Bit 7 (MSB) is the start of the
default hexadecimal value given. For example, Address 0x14,
the output mode register, has a hexadecimal default value of
0x05. This means that Bit 0 = 1 and Bit 2 = 1, and the remaining
bits are 0s. This setting is the default output format value, which
is twos complement. For more information on this function and
others, see the
Speed ADCs via SPI. This document details the functions
controlled by Register 0x00 to Register 0x25. The remaining
registers, Register 0x3A, is documented in the Memory Map
Register Description section.
Open and Reserved Locations
All address and bit locations that are not included in Table 14
are not currently supported for this device. Unused bits of a
valid address location should be written with 0s. Writing to these
locations is required only when part of an address location is
open (for example, Address 0x18). If the entire address location
is open (for example, Address 0x13), this address location should
not be written.
Default Values
After the AD9643 is reset, critical registers are loaded with
default values. The default values for the registers are given in
the memory map register table, Table 14.
AN-877 Application
Note, Interfacing to High
Rev. B | Page 31 of 36
Logic Levels
An explanation of logic level terminology follows:
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•
Transfer Register Map
Address 0x08 to Address 0x20 and Address 0x3A are shadowed.
Writes to these addresses do not affect part operation until a
transfer command is issued by writing 0x01 to Address 0xFF,
setting the transfer bit. This allows these registers to be updated
internally and simultaneously when the transfer bit is set. The
internal update takes place when the transfer bit is set, and then
the bit autoclears.
Channel-Specific Registers
Some channel setup functions, such as the signal monitor
thresholds, can be programmed to a different value for each
channel. In these cases, channel address locations are internally
duplicated for each channel. These registers and bits are designated
in Table 14 as local. These local registers and bits can be accessed
by setting the appropriate Channel A or Channel B bits in
Register 0x05. If both bits are set, the subsequent write affects
the registers of both channels. In a read cycle, only Channel A
or Channel B should be set to read one of the two registers. If
both bits are set during an SPI read cycle, the part returns the
value for Channel A. Registers and bits designated as global in
Table 14 affect the entire part and the channel features for which
independent settings are not allowed between channels. The
settings in Register 0x05 do not affect the global registers and bits.
“Bit is set” is synonymous with “bit is set to Logic 1” or
“writing Logic 1 for the bit. ”
“Clear a bit” is synonymous with “bit is set to Logic 0” or
“writing Logic 0 for the bit. ”
AD9643