SA58646 Datasheet, PDF (20/42 Pages) NXP Semiconductors – UHF 900 MHz transceiver IC

NXP Semiconductors
SA58646
UHF 900 MHz transceiver IC
Table 14. Data register 4 (address 100h) bit description …continued
Legend: * reset value.
Bit
Symbol
Value Description
12
DOUBLER
Voltage doubler. The minimum supply voltage for the IC is
2.9 V which limits the voltage swing on both charge pumps
to approximately 2.3 V. Using the voltage doubler or an
external high supply voltage on pin VCP, allows the
increased voltage range to enhance the tuning range of the
VCO varicaps. To save current in Inactive mode, the
voltage doubler clock frequency is the same as the CLKO
clock (can be programmed to XTAL / 128); in Active mode,
the voltage doubler clock is XTALI / 2.
0* doubler inactive
1
doubler active
11 to 7 TX_GAIN[4:0]
TX gain setting
01 for values, see Table 9
1111*
6
TX_MU
TX channel mute
0
not muted (normal operation)
1* muted
5
HD_LIM
Hard limiter
0* disable
1
enable
5
ALC
Automatic level control
0* enable (normal operation)
1
disable
3
XTAL
Crystal oscillator
0
on
1* off
2
RX_MU
RX channel mute
0
not muted (normal operation)
1* muted
1
DEM_FIL
Demodulator filter. An internal programmable filter limits
the demodulator bandwidth. The −3 dB cut-off frequency is
selected with this bit. The wider bandwidth provides a
solution for audio and sub-audio digital applications.
0* 7 kHz
1
100 kHz
0
reserved
0* undefined, must always be set to logic 0
SA58646_1
Product data sheet
Rev. 01 — 8 February 2007
© NXP B.V. 2007. All rights reserved.
20 of 42