Analog Devices ADRV9002

UG-1828 Preliminary Technical Data
Rev. PrB | Page 66 of 277
Delay Description
Provided
By
Bounds Comments
propagationDelay
(t
RxPD
)
Propagation delay from
antenna to Rx interface.
Helper
Parameter
Min: N/A
Max: N/A
This parameter should be measured
by user and it is profile dependent
and board layout dependent. It
does not need to provide to
ADRV9001, however, it can be used
to derive values for other
parameters required by ADRV9001.
enableRiseToAnalogOnDelay
(t
RxEnaRise2AnaOn
)
Delay between RX_ENABLE
rising edge to start of Rx
analog power up.
User
Parameter
Min: 0
Max: duration of power
up tasks in power
savings or frequency
hopping modes.
Will only be set to non-zero values if
using power savings or frequency
hopping. See later sections to
determine how to choose a non-
zero value.
enableRiseToOnDelay
(t
RxEnaRise2On
)
Delay between RX_ENABLE
rising edge and LNA power
up.
If ADRV9001 does not
controlling LNA power, this
parameter is not needed.
User
Parameter
Min: t
RxEnaRise2AnaOn
Typ: t
RxEnaRise2AnaOn
+
t
RxEnaSetup
Max: None. Must be
optimized to be
minimal.
If set to t
RxEnaRise2AnaOn
, the actual
delay is t
RxEnaRise2AnaOn
+ t
RxEnaSetup
.
enableGuardDelay
(t
RxGT
)
Guard time of the Rx frame.
Reserved for future use.
Should set to 0 currently.
User
Parameter
Min: TBD
Max: TBD
TBD
enableFallToOffDelay
(t
RxEnaFall2Off
)
Delay between RX_ENABLE
falling edge and the
powering down the LNA.
(If ADRV9001 not
controlling LNA power, this
parameter can still be used
to delay analog power
down. ADRV9001 forces it
to 0 currently. LNA is
disabled at the same time
when Rx is disabled.)
User
Parameter
Min: 0
Max: None. Must be
optimized to be
minimal.
Ideally, RX_ENABLE falling edge
arrives when the last valid data is
received over the air. By setting this
value greater than 0, ADRV9001 can
continue receiving guard symbols,
while signaling to certain
algorithms or other systems that
the valid data for the frame has
already been received.
enableHoldDelay
(t
RxEnaHold
)
Delay between RX_ENABLE
falling edge and masking
off datapath data sent over
interface.
User
Parameter
Min: t
RxEnaFall2Off
Max: None. Must be
optimized to be
minimal.
(Recommended Max:
t
RxEnaFall2Off
+ t
RxPD
Note
t
RxEnaFall2Off
is forced to 0
currently.)
The interface is disabled only after
analog power down has completed.
@ min bound: Some of the data
received at the antenna may not
make it over the interface.
@ max bound: Digital datapath and
Rx SSI interface remains enabled
until last received data is
propagated to the interface.
Design Strategy for Receive Timing Parameters
As described in Table 23, ADRV9001 provides user enableSetupDelay which is the time required to power up the receiver front end. By
knowing that, user could set the RX_ENABLE pin high at least enableRiseToOnDelay in advance as shown in Figure 56. In regular TDD
mode, that is, no power savings or frequency hopping, enableRiseToAnalogOnDelay should always be set to 0, so that analog power up
begins immediately after receive enable rising edge (Note Figure 56 describes receive timing parameters in a general case with
enableRiseToAnalogOnDelay not equal to 0.). The parameter enableRiseToOnDelay could also be set to 0, in this case, the LNA is
powered up as soon as analog power up completes. For a more deterministic delay between RX_ENABLE rising edge and LNA power up
time, enableRiseToOnDelay can be set to a value greater than or equal to
enableRiseToAnalogOnDelay + enableSetupDelay
Once timing on air is established, the user may choose to raise RX_ENABLE, sometime before the start of the actual frame. As soon as
the Rx analog power up completes, the digital interface turns on, however, if the path has a long propagation delay, the initial data
coming off the interface are not the data received over the air.
When the frame ends, users may wish to continue receiving for a while, however, ADRV9001 may wish to stop all the tracking
algorithms to avoid any performance degradation. This can be achieved by bringing the RX_ENABLE signal low as soon as the frame