T5744-TKS Atmel, T5744-TKS Datasheet - Page 4

• Manufacturer Part Number: T5744-TKS
• Description: RF Transceiver UHF ASK Receiver IC
• Manufacturer: Atmel

Specifications of T5744-TKS

• Operating Supply Voltage: 5 V
• Mounting Style: SMD/SMT
• Package / Case: SSO-20
• Minimum Operating Temperature: - 40 C
• Operating Frequency (max): 450000kHz
• Operating Temperature (min): -40C
• Operating Temperature (max): 105C
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4
T5744
The XTO is a one-pin oscillator that operates at the series resonance of the quartz crystal.
According to
of that capacitor is recommended by the crystal supplier. The value of CL should be optimized
for the individual board layout to achieve the exact value of f
ing the system in terms of receiving bandwidth, the accuracy of the crystal and the XTO must be
considered.
Figure 3-1.
The passive loop filter connected to pin LF is designed for a loop bandwidth of B
This value for B
the appropriate loop filter components to achieve the desired loop bandwidth
f
formula:
f
To determine f
frequency is f
is tuned by the crystal frequency f
f
MODE = 0 USA f
MODE = 1 Europe f
The relation is designed to achieve the nominal IF frequency of f
tions. For applications where f
f
f
rizes the different conditions.
The RF input either from an antenna or from a generator must be transformed to the RF input
pin LNA_IN. The input impedance of that pin is provided in the electrical parameters. The para-
sitic board inductances and capacitances also influence the input matching. The RF receiver
T5744 exhibits its highest sensitivity at the best signal-to-noise ratio in the LNA. Hence, noise
matching is the best choice for designing the transformation network.
LO
LO
LO
RF
IF
is then dependent on the logical level at pin MODE and on f
= f
that depends on the logic level at pin mode. This is described by the following formulas:
= 433.92 MHz, MODE must be set to '1'. For other RF frequencies, f
is determined by the RF input frequency f
RF
– f
IF
Figure
IF
LO
PLL Peripherals
= 1 MHz. To achieve a good accuracy of the filter's corner frequencies, the filter
Loop
, the construction of the IF filter must be considered at this point. The nominal IF
IF
= f
IF
3-1, the crystal should be connected to GND via a capacitor CL. The value
exhibits the best possible noise performance of the LO.
LO
= f
/314
LO
/432.92
LFGND
LFVCC
DVCC
XTO
LF
XTO
RF
= 315 MHz, MODE must be set to '0'. In the case of
. This means that there is a fixed relation between f
V
V
S
S
C9
R1
RF
and the IF frequency f
C10
C
L
C9 = 4.7 nF
C10 = 1 nF
R1 = 820
XTO
RF
and hereby of f
.
Table 3-1 on page 5
IF
= 1 MHz for most applica-
IF
is not equal to 1 MHz.
IF
using the following
Figure 3-1
LO
. When design-
Loop
4521C–RKE–05/05
= 100 kHz.
summa-
shows
IF
and