TDA5211XT Infineon Technologies, TDA5211XT Datasheet - Page 26

• Manufacturer Part Number: TDA5211XT
• Manufacturer: Infineon Technologies

Specifications of TDA5211XT

• Operating Temperature (min): -40C
• Operating Temperature Classification: Automotive
• Product Depth (mm): 4.4mm
• Product Length (mm): 9.7mm
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Compliant

Wireless Components
4.4 Quartz Frequency Calculation
As described in Section 3.4.3 the operating range of the on-chip VCO is wide
enough to guarantee a receive frequency range between 310 and 350MHz. The
VCO signal is divided by 2 before applied to the mixer . This local oscillator sig-
nal can be used to downconvert the RF signals both with high- or low-side injec-
tion at the mixer. High-side injection of the local oscillator has to be used for
receive frequencies between 310 and 330 MHz. In this case the local oscillator
frequency is calculated by adding the IF frequency (10.7 MHz) to the RF fre-
quency. In this case the higher frequency of a FSK-modulated signal is
demodulated as a logical one (high).
Low-side injection has to be used for receive frequencies between 330 and
350 MHz. The local oscillator frequency is calculated by subtracting the IF fre-
quency (10.7 MHz) from the RF frequency then. Please note that in this case
sign-inversion occurs and the higher frequency of a FSK-modulated signal is
demodulated as a logical zero (low). The overall division ratios in the PLL are
64 or 32 depending on whether the CSEL-pin is left open or tied to ground.
Therefore the quartz frequency may be calculated by using the following for-
mula:
with
This yields the following examples:
CSEL tied to GND:
CSEL open:
Table 4-1 PLL Division Ratio Dependence on States of CSEL
ƒ
ƒ
ƒ
ƒ
r
QU
RF
LO
QU
= (ƒ
f
f
f
f
receive frequency
local oscillator (PLL) frequency (ƒ
quartz oscillator frequency
ratio of local oscillator (PLL) frequency and quartz frequency as
shown in the subsequent table
QU
QU
QU
QU
RF
CSEL
open
GND
±
315
345
315
345
10.7) / r
4 - 6
MHz
MHz
MHz
MHz
10
10
10
10
7 .
7 .
7 .
7 .
MHz
MHz
MHz
MHz
/
/
/
/
32
32
64
64
RF
±
Ratio r = (f
10
10.7)
10
. 5
. 5
.
.
2234
4469
0891
1781
Specification, May 2001
64
32
LO
MHz
MHz
MHz
MHz
/f
QU
Applications
TDA 5211
)