TDA5150 Datasheet, PDF (38/106 Pages) Infineon Technologies AG – On-chip, high resolution fractional-N synthesizer and Sigma-Delta modulator with ASK, FSK, GFSK options

TDA 5150
TDA 5150 Functional Description
2.4.6.4 PLL Dividers, RF Carrier Frequency
The divider chain contains a fixed divider by 2 (prescaler), a band select divider, dividing
by 1 for the 915 and 868 MHz bands, by 2 for the 434 MHz band, and by 3 for the 315
MHz band. The divider ratio of this block is controlled by the field SMB0/1 of SFR
TXCFG0 (0x04.3:2).This band selection block is followed by the Multi-Modulus Divider,
which is controlled by the Sigma-Delta Modulator. The RF frequency is set in the PLL
Integer and PLL Fractional SFRs. Up to 4 different frequencies may be preconfigured in
the same band (Frequency Registers A, B, C, D) and finally the active channel selected
through the Transmit Command. This allows fast channel switching or hopping, without
the need of downloading the complete reconfiguration dataset into the corresponding
SFRs (i.e the new PLL settings).
The RF frequency f_RF is derived from the crystal frequency.
f_RF
=
f_X
O
SC
×
⎛
⎝
P
L
L
I
N
T
<
6:0
>
+
-^P----^L---^L----^F----^R-----^A-₂---^C₂---₁-^<--_–----²-₀--⁰-_.-₅-^:--⁰----^>------⁺-----⁰---^.-⁵--_⎠⎞
For the 315 MHz and 433 MHz bands (ISMB<1> = 0) PLLINT bit 6 is not used and only
values from 15 to 43 are valid.
For the 868 MHz and 915 MHz bands (ISMB<1> = 1) all PLLINT bits are used and
values between 54 and 84 are valid.
2.4.6.5 SFRs related to Sigma-Delta fractional-N PLL Block
ADDR 0x04
TXCFG0—Transmitter Configuration Register 0
Bit 7
GO2STDBY
cw/0
Bit 6
reserved
w/0
Bit 5
reserved
w/0
Bit 4
FSOFF
w/0
Bit 3
ISMB
w/0
Bit 2
ISMB
w/1
Bit 1
reserved
w/1
Bit 0
reserved
w/0
Bit 7
GO2STDBY 1: activate
STANDBY
Bit 6 ^FSOFF
1: activate
FAILSAFE
Bit <3:2> ^ISMB
RF frequency band bits
ISMB
ISM band selection (2-bits)
00: MHz
300-320
01: MHz
425-450
10: MHz
863-870
11: MHz
902-928
Data Sheet
38
V 1.0, July 2009