AD9640 Analog Devices, AD9640 Datasheet - Page 42

• Manufacturer Part Number: AD9640
• Description: 14-Bit, 80/105/125/150 MSPS, 1.8 V Dual Analog-to-Digital Converter
• Manufacturer: Analog Devices

Specifications of AD9640

• Resolution (bits): 14bit
• # Chan: 2
• Sample Rate: 150MSPS
• Interface: Par
• Analog Input Type: Diff-Uni
• Ain Range: 1 V p-p,2 V p-p
• Adc Architecture: Pipelined
• Pkg Type: CSP

AD9640
MEMORY MAP
READING THE MEMORY MAP TABLE
Each row in the memory map table has eight bit locations. The
memory map is roughly divided into four sections: chip configura-
tion and ID register map (Address 0x00 to Address 0x02); ADC
setup, control, and test (Address 0x08 to Address 0x25); the
channel index and transfer register map (Address 0x05 to
Address 0xFF); and digital feature control (Address 0x100 to
Address 0x11B).
Starting from the right hand column, the memory map register
in Table 25 documents the default hex value for each hex address
shown. The column with the heading Bit 7 (MSB) is the start
of the default hex value given. For example, Address 0x18, VREF
select, has a hex default value of 0xC0. This means Bit 7 = 1,
Bit 6 = 1, and the remaining bits are 0s. This setting is the default
reference selection setting. The default value uses a 2.0 V peak-
to-peak reference. For more information on this function and
others, see the AN-877 Application Note, Interfacing to High Speed
ADCs via SPI. This document details the functions controlled by
Register 0x00 to Register 0xFF. The remaining registers, from
Register 0x100 to Register 0x11B, are documented in the Memory
Map Register Description section.
Open Locations
All address and bit locations that are not included in Table 25
are currently not 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
Coming out of reset, critical registers are loaded with default
values. The default values for the registers are given in the
memory map register table, Table 25.
Rev. B | Page 42 of 52
Logic Levels
An explanation of logic level terminology follows:
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Transfer Register Map
Address 0x08 to Address 0x18 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 simulta-
neously when the transfer bit is set. The internal update takes
place when the transfer bit is set, and the bit autoclears.
Channel-Specific Registers
Some channel setup functions, such as the signal monitor
thresholds, can be programmed differently for each channel.
In these cases, channel address locations are internally duplicated
for each channel. These registers are designated in the parameter
name column of Table 25 as local registers. These local registers
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 designated as global
in the parameter name column of Table 25 affect the entire part
or the channel features where independent settings are not
allowed between the channels. The settings in Register 0x05
do not affect the global registers.
“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. ”