SA58646 Datasheet, PDF (24/42 Pages) NXP Semiconductors – UHF 900 MHz transceiver IC

NXP Semiconductors
SA58646
UHF 900 MHz transceiver IC
Table 18. Data register 6 (address 110h) bit description …continued
Legend: * reset value.
Bit
Symbol
Value Description
10 to 8 REG_ADJ[2:0]
Voltage regulator adjustment. An internal 1.5 V band gap
voltage reference provides the voltage reference for the low
battery detector circuits, the VREG regulator voltage, the
VB reference voltage and all internal analog references. In
Inactive mode, the adjustment is disabled.
011* for values, see Table 21
7 to 6 EXP[1:0]
Expander noise level control. Depending on the
application noise floor specification, a noise level control
can be applied.
00* expander disabled
11 expander maximum value
5
TM0
0* Test mode selection. Test mode bits are only used for test
in production and application tuning. Those bits have to be
set to logic 0 for normal operation. See Table 22.
4
reserved
0* undefined; must always be set to logic 0
3 to 0 XTAL_TUN[3:0]
Crystal tuning capacitors. An on-chip crystal reference
tuning is provided to compensate for frequency spread
over process and temperature. The value of the external
capacitor on pin XTALI is chosen to be around 3 pF lower
than on pin XTALO. Internally, a programmable
capacitance is in parallel with pin XTALI. Tuning
capacitance values are in the range of 0 pF to 4.5 pF.
0111* for values, see Table 19
Table 19. Crystal tuning capacitance
Select XTAL_TUN[3:0]
Bit 3 Bit 2 Bit 1 Bit 0
0
0
0
0
0
1
0
0
0
1
2
0
0
1
0
3
0
0
1
1
4
0
1
0
0
5
0
1
0
1
6
0
1
1
0
7
0
1
1
1
8
1
0
0
0
9
1
0
0
1
10
1
0
1
0
11
1
0
1
1
12
1
1
0
0
13
1
1
0
1
14
1
1
1
0
15
1
1
1
1
Capacitance (pF)
0.2
0.5
0.8
1.1
1.4
1.7
2.0
2.3
2.6
2.9
3.2
3.5
3.8
4.1
4.4
4.7
SA58646_1
Product data sheet
Rev. 01 — 8 February 2007
© NXP B.V. 2007. All rights reserved.
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