AD1836A View Datasheet(PDF) - Analog Devices
Part Name
Description
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AD1836A Datasheet PDF : 24 Pages
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AD1836A
through an FPGA or other large digital chip before being
applied to the AD1836A. In most cases, this will induce clock
jitter due to the fact that the clock signal is sharing common
power and ground connections with other unrelated digital
output signals.
The six DAC channels use a common serial bit clock to clock in
the serial data and a common left-right framing clock. The four
ADC channels output a common serial bit clock and a left-right
framing clock. The clock signals are all synchronous with the
sample rate.
RESET AND POWER-DOWN
Reset will power down the chip and set the control registers to
their default settings. After reset is de-asserted, an initialization
routine will run inside the AD1836A to clear all memories to
zero. This initialization lasts for approximately 4500 MCLKs.
The power-down bit in the DAC Control Register 1 and ADC
Control Register 1 will power down the respective digital
section. The analog circuitry does not power down. All other
register settings are retained.
To avoid possible synchronization problems, if MCLK is 512 fS
or 768 fS, the clock rate should be set in ADC Control Register 3
within the first 3072 MCLK cycles after reset, or DLRCLK and
DBCLK should be withheld until after the internal initialization
completes (see above).
SERIAL CONTROL PORT
The AD1836A has an SPI compatible control port that permits
programming the internal control registers for the ADCs and
DACs and for reading the ADC signal level from the internal
peak detectors. The DAC output levels may be independently
programmed by means of an internal digital attenuator
adjustable in 1024 linear steps.
The SPI control port is a 4-wire serial control port. The format
is similar to the Motorola SPI format except the input data-word
is 16 bits wide. The maximum serial bit clock frequency is 8 MHz
and may be completely asynchronous to the sample rate of the
ADCs and DACs. Figure 3 shows the format of the SPI signal.
All control registers are write-only. They cannot be read back.
The ADC peak registers are read-only. They are reset to zero each
time they are read and are updated at the next sample time.
Due to an anomaly in the SPI interface, when a write to a DAC
control register follows after a read or a write to an ADC
register, it may not be executed properly. Any such write should
be performed twice.
CLATCH
CCLK
CDATA
D15
D14
D0
COUT
D9
D8
D0
Figure 3. Format of SPI Signal
Rev. 0 | Page 12 of 24
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