srf-2724cs RF Micro Devices, srf-2724cs Datasheet - Page 12

• Manufacturer Part Number: srf-2724cs
• Description: 2.4ghz Low-if 1.5mbps Fsk Transceiver
• Manufacturer: RF Micro Devices

SRF-2724CS
There are three key modes of operation:
• STANDBY:All circuits powered down, except the control interface (Static CMOS)
• RECEIVE:Receiver circuits active
• TRANSMIT:Modulated RF output from IC
The two operational modes are RECEIVE and TRANSMIT, controlled by RXON. XCEN is the chip enable/disable control pin,
which sets the part in operational or STANDBY modes. The relationship between the parallel control lines and the mode of
operation of the IC is given in Table 1:
Table 1
Mode Control
The SRF-2724CS is intended for use in TDD and TDMA radios in battery-powered equipment. To minimize power consumption
it is designed to switch rapidly from a low power mode (STANDBY) to an active mode. The SRF-2724CS can also make a quick
transition from receive to transmit for TDD operation. Prior to transmitting or receiving, time should be allowed for the PLL to
lock and for the filters to align. When the SRF-2724CS is operated in single-carrier TDD mode, the LO is automatically shifted
by the second (low) IF frequency when the device is switched between RECEIVE and TRANSMIT modes.
SRF-2724CS carrier frequency can be changed (hopped) at any time, but is usually changed between transmissions. Carrier
frequency (channel) is modified in the SRF-2724CS by writing a corresponding new value to the PLL frequency register (Regis-
ter 1)
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XCEN
0
1
1
RXON
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X
1
0
RVVCO
QPO
Example: 13kHz Loop Filter
33nF
Modes of Operation
TRANSMIT
STANDBY
RECEIVE
Mode
Control interfaces active, all other circuits powered down
Proposed
150Ω
220nF
VTUNE
Receiver time slot
Transmit time slot
Function
Prelim DS090410