DS2722-F-03 MICRO-LINEAR [Micro Linear Corporation], DS2722-F-03 Datasheet - Page 15

• Manufacturer Part Number: DS2722-F-03
• Description: 900MHz Low-IF 1.5Mbps FSK Transceiver Final Datasheet
• Manufacturer: MICRO-LINEAR [Micro Linear Corporation]

OVERVIEW
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The two operational modes are RECEIVE and TRANSMIT. They are set by the RXON control (pin 2). XCEN (pin 1) is
the chip enable/disable and can be set for standby operation. The relationship between the parallel control lines and the
mode of operation of the IC is given in Table 1.
M
The ML2722 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 receive or transmit. The ML2722
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 up and for the filters to be aligned. When the ML2722 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.
ML2722 carrier frequency can be changed (hopped) between transmissions. Carrier frequency (channel) is modified in
the ML2722 by writing a corresponding new value to the PLL frequency register.
RECEIVE
The ML2722 uses a single-conversion heterodyne receiver with a nominal IF of 1.024MHz. The signal flow in RECEIVE
mode is from the RF input, through an image reject quadrature mixer, limiter, frequency-to-voltage converter, data filter,
and data slicer where the digital NRZ data is available at the DOUT pin. A 20dB step AGC extends the dynamic range
of the receiver.
The ML2722 receive chain is a Low IF receiver using advanced integrated radio techniques to eliminate external IF
filters and minimize external RF filter requirements. The precision filtering and demodulation circuits give improved
performance over conventional radio design using external filters while providing integration comparable to advanced
direct conversion radio designs.
DS2722-F-05
ODE
MODES OF OPERATION
STANDBY:
RECEIVE:
TRANSMIT:
C
ONTROL
XCEN
0
1
1
All circuits powered down, except the control interface (Static CMOS)
Receiver circuits active
PLL open loop, modulated RF output available from the IC
RXON
X
1
0
TRANSMIT
STANDBY
RECEIVE
FINAL DATASHEET
MODE
Table 1: Modes of Operation
Control interfaces active, all other circuits powered down
Receiver time slot
Transmit time slot
TRANSCEIVER MODE
DECEMBER 2003
ML2722
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