SA58646 Datasheet, PDF (9/42 Pages) NXP Semiconductors – UHF 900 MHz transceiver IC

NXP Semiconductors
SA58646
UHF 900 MHz transceiver IC
7.2 FM receiver part
The FM receiver has a single frequency conversion architecture. The image reject mixer
enables the user to save an RF filter. The side band select feature (bit SBS) enables the
user to choose its frequency plan with RX LO in or out of ISM band and have the same IC
for both base and handset. An IF channel filtering compromise between price and
performance can be achieved using two or three 10.7 MHz external filters. The integrated
FM PLL demodulator with limiter enables consistent saving on external components and
pins.
The data comparator is an inverting hysteresis comparator. The open-collector output is
current limited to control the output signal slew rate. An external band-pass filter is
connected between pins DETO and DATAI (AC coupled). The external resistor should be
180 kΩ at maximum V_CC. An external capacitor can be added to further reduce the slew
rate.
IF
10.7 MHz
IF
10.7 MHz
IF
10.7 MHz
LNA
RFIX
RFIY
mixer
+90°
mixer
MIXO IFA1I IFA1O IFA2I IFA2O LIMI
SFS
IFamp1
IFamp2
limiter
LPFD
DEM_FIL
mixer
LOOP
FILTER
VCO
SBS
QUADRATURE
PHASE SHIFTER
RXLOX RXLOY
D_PHASE
DUAL PLL
FREQUENCY
SYNTHESIZER
XTAL
VCO RX
VREG
RX
RXPD RXLOX
LPF
RXLF RXLOY VRX
FM_PLL_VCO
[4:0]
CAR_DET_LEV
[4:0]
RSSI _VB
amplifier
DETO
PLLO
data
amplifier
DATAI
BAT_DET
RSSI
CDLBD
DATAO
Fig 3. FM receiver part
001aaf618
SA58646_1
Product data sheet
Rev. 01 — 8 February 2007
© NXP B.V. 2007. All rights reserved.
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