Analog Devices ADRV9001 User Manual page 68

UG-1828
Guard Time Between TX_ENABLE Falling Edge and Tx_enable Rising Edge
The guard time between TX_ENABLE falling edge and TX_ENABLE rising edge is for making sure that the interface is turned off at the
end of the previous frame before it turns on again for the next frame. In addition, it must also make sure that the analog front end has
been powered off in the previous frame prior to powering up again in the new frame. Because it takes t
interface after the TX_ENABLE falling edge, the next TX_ENABLE rising edge must come after a delay of at least t
that the interface is turned off at the end of the previous frame before it turns on again for the next frame. Since it takes t
power down the transmitter analog front end after the TX_ENABLE falling edge, the next TX_ENABLE rising edge must come after a
delay of at least equal to t
TxEnaFall2Off
to powering up again in the new frame. If the timing parameters are set appropriately, these two conditions are almost identical. If they
are not identical for some reason, the guard time should be set as the maximum (t
this scenario.
Guard Time Between RX_ENABLE Falling Edge and RX_ENABLE Rising Edge
The guard time between the RX_ENABLE falling edge and RX_ENABLE rising edge is for making sure that the interface is turned off at
the end of the previous frame before it turns on again for the next frame. Because it takes t
RX_ENABLE falling edge, the next RX_ENABLE rising edge must come after a delay of at least t
turned off at the end of the previous frame before it turns on again for the next frame. Because the analog powers down before the
interface, the analog front end is guaranteed to power down prior to being powered up at the start of the next frame if this condition is
met. Figure 60 describes this scenario.
Hold Time Between TX_ENABLE Rising Edge and TX_ENABLE Falling Edge
After a TX_ENABLE rising edge, its falling edge must come after a delay of at least t
switch). In order to actually transmit, the channel must be on for a duration longer than its propagation delay. This can be achieved,
either by making sure TX_ENABLE is high for longer than the propagation delay, or by ensuring the t
than t . Figure 61 describes this scenario.
TxPD
Hold Time Between RX_ENABLE Rising Edge and RX_ENABLE Falling Edge
After a RX_ENABLE rising edge, its falling edge must come after a delay of at least t
In order to actually receive data, the channel must be on for a duration longer than its propagation delay. This can be achieved, either by
making sure RX_ENABLE is high for longer than the propagation delay or by ensuring the t
describes this scenario.
Timing Parameters with Power Savings Modes
ADRV9001 offers several channel power savings modes (Power Saving Mode 0, Power Saving Mode 1, and Power Saving Mode 2) that
trade off better power savings with longer transition time to turn on and turn off a transmit or receive channel. Please refer to the Power
Saving and Monitor Mode section in this User Guide for more details about power saving modes. In order to take advantage of these
power saving modes, the timing parameters must be set appropriately.
− t . This ensures that the analog front end has been powered off in the previous frame prior
TxEnaRise2AnaOn
MAX (t
TxEnaHold
Figure 59. Minimum Guard Time Between TX_ENABLE Falling Edge and TX_ENABLE Rising Edge
Figure 60. Minimum Guard Time Between RX_ENABLE Falling Edge and RX_ENABLE Rising Edge
Figure 61. Minimum Hold Time between TX_ENABLE Rising Edge and TX_ENABLE Falling Edge
Figure 62. Minimum Hold Time Between RX_ENABLE Rising Edge and RX_ENABLE Falling Edge
TxEnaHold
Tx_ENABLE
, t – t
TxEnaFall2Off TxEnaRise2On
Rx_ENABLE
t
RxEnaHold
TxEnaRise2AnaOn
Tx_ENABLE
t
TxPD
RxEnaRise2AnaOn
Rx_ENABLE
t
RxPD
t
RxEnaRise2On
Rev. PrA | Page 68 of 253
Preliminary Technical Data
to turn off the transmit
TxEnaHold
, t − t ). Figure 59 describes
TxEnaFall2Off TxEnaRise2AnaOn
)
to turn off the receive interface after the
RxEnaHold
. This ensures that the interface is
RxEnaHold
or t (if controlling antenna
TxEnaRise2On
and t
TxEnaHold
or t (if controlling LNA power).
RxEnaRise2On
is longer than t
RxEnaHold
. This ensures
TxEnaHold
to
TxEnaFall2Off
are longer
TxEnaFall2Off
. Figure 62
RxPD