uaa3540ts NXP Semiconductors, uaa3540ts Datasheet - Page 5

• Manufacturer Part Number: uaa3540ts
• Description: Dect Receiver
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FUNCTIONAL DESCRIPTION
General
The UAA3540TS is a fully integrated RF plus IF strip and
demodulator for DECT applications. It provides all the
required channel filtering over the DECT band and
generates analog RSSI and a data output for the
baseband chip. Very few off-chip components are required
and should not require trimming in normal applications.
The chip is designed to operate from a power supply
voltage which can fall to 3.0 V, and features full
power-down capabilities.
The inputs are an RF antenna signal and a Local
Oscillator (LO) signal. The RF antenna signal is from a
band filter or antenna switch. The higher frequency
LO signal is from an external Voltage Controlled
Oscillator (VCO).
The outputs are an RSSI voltage, representing the
instantaneous signal strength, and DATA and DATA+
which are two high-level demodulator output signals.
DATA is switched by SLCCTR to generate a threshold
voltage for the internal slicer, and DATA+ is the
comparator digital output.
Filter
The integrated filter provides all the channel selectivity
required for the DECT receiver. An external resistor of
18 k must be connected to RSET (pin 8).
2000 Feb 15
DECT receiver
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Limiter and RSSI
The main purpose of the limiter circuit is to reduce the
dynamic range of the signals presented to the
demodulator; these have a dynamic range greater than
60 dB.
The limiter also provides the RSSI output voltage.
The RSSI output has very little filtering applied, and it is
assumed that external circuits will be used to provide the
time constant and peak holding required by the DECT
specification.
Demodulator
The demodulator produces an output voltage directly
proportional to the instantaneous frequency of the
received signal. The output stage of the demodulator
contains a data filter to remove high frequencies from the
signal, prior to data slicing.
The demodulator provides a continuous output timing
signal that is applied to an internal data slicer. The same
signal is also switched to generate the threshold voltage of
the slicer during the initial DECT bit sequence.
Power-down
The power-down control input (pin 2) allows the current
consumption of the chip to be reduced to a very low level
when it is connected to V
the chip become indeterminate requiring time for the
receiver to stabilize after power-up.
CC
. In this state, some voltages in
UAA3540TS
Product specification