T5760NTGS Atmel, T5760NTGS Datasheet - Page 7

• Manufacturer Part Number: T5760NTGS
• Manufacturer: Atmel

Specifications of T5760NTGS

• Operating Temperature (min): -40C
• Operating Temperature (max): 105C
• Operating Temperature Classification: Industrial
• Lead Free Status / Rohs Status: Not Compliant

5. Receiving Characteristics
4561C–RKE–05/05
The cut-off frequency of the lowpass filter is defined by the selected baud-rate range
(BR_Range). The BR_Range is defined in the OPMODE register (refer to section
of the Receiver” on page
The T5760/T5761 is designed to operate with data coding where the DC level of the data signal
is 50%. This is valid for Manchester and Bi-phase coding. If other modulation schemes are used,
the DC level should always remain within the range of V
sensitivity may be reduced by up to 2 dB in that condition.
Each BR_Range is also defined by a minimum and a maximum edge-to-edge time (t
These limits are defined in the electrical characteristics. They should not be exceeded to main-
tain full sensitivity of the receiver.
The RF receiver T5760/T5761 can be operated with and without a SAW front-end filter. In a typ-
ical automotive application, a SAW filter is used to achieve better selectivity and large signal
capability. The receiving frequency response without a SAW front-end filter is illustrated in
ure 5-1
similar behavior. The plots are printed relatively to the maximum sensitivity. If a SAW filter is
used, an insertion loss of about 3 dB must be considered, but the overall selectivity is much
better.
When designing the system in terms of receiving bandwidth, the LO deviation must be consid-
ered as it also determines the IF center frequency. The total LO deviation is calculated, to be the
sum of the deviation of the crystal and the XTO deviation of the T5760/T5761. Low-cost crystals
are specified to be within ±90 ppm over tolerance, temperature and aging. The XTO deviation of
the T5760/T5761 is an additional deviation due to the XTO circuit. This deviation is specified to
be ±30 ppm worst case for a crystal with CM = 7 fF. If a crystal of ±90 ppm is used, the total
deviation is ±120 ppm in that case. Note that the receiving bandwidth and the IF-filter bandwidth
are equivalent in ASK mode but not in FSK mode.
Figure 5-1.
and
Figure 5-2 on page
Narrow Band Receiving Frequency Response
-20.0
-30.0
-40.0
-60.0
-50.0
-10.0
22). The BR_Range must be set in accordance to the used baud-rate.
0.0
-4.0
-3.0
8. This example relates to ASK mode. FSK mode exhibits a
-2.0
-1.0
df (MHz)
0.0
1.0
DC_min
2.0
= 33% and V
3.0
T5760/T5761
4.0
DC_max
“Configuration
= 66%. The
ee_sig
Fig-
).
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