RFRXD0420T-I/LQ Microchip Technology, RFRXD0420T-I/LQ Datasheet - Page 9

• Manufacturer Part Number: RFRXD0420T-I/LQ
• Description: IC RCVR 315/433MHZ ASK/FSK32LQFP
• Manufacturer: Microchip Technology

Specifications of RFRXD0420T-I/LQ

• Frequency: 300MHz ~ 450MHz
• Sensitivity: -106dBm
• Data Rate - Maximum: 80 kbps
• Modulation Or Protocol: ASK, FM, FSK
• Applications: Home Automation, Remote Sensing, RKE
• Current - Receiving: 9.2mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-LQFP
• For Use With: DV164102 - KIT DEV RFPICKIT KIT 1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -

3.0
This section provides general information on applica-
tion circuits for the rfRXD0420/0920 receiver. The
following connections and external components
provide starting points for designs and list the minimum
circuitry
applications.
Performance of the radio system (transmitter and
receiver) is affected by component selection and the
environment in which it operates. Each system design
has its own unique requirements. Specifications for a
particular design requires careful analysis of the appli-
cation and compromises for a practical implementation.
3.1
This subsection lists connections and components that
are common between applications. The following
subsections give specific circuit connections and
components for ASK, FSK and FM applications.
3.1.1
Bypass capacitors should be placed as physically close
as possible to V
respectively. Additional bypassing and board level low-
pass filtering of the power supply may be required
depending on the application.
3.1.2
The rfRXD0420/0920 receivers are single-conversion
superheterodyne
frequency. The receive frequency is set by the crystal
frequency (f
a majority of applications an external crystal is
connected to XTAL (Pin 26). Figure 3-1 illustrates an
example circuit with an optional trim capacitor.
FIGURE 3-1:
The crystal load capacitance should be specified to
include the internal load capacitance of the XTAL pin of
15 pF plus PCB stray capacitance (approximately 2 to
3 pF). A trim capacitor can be used to trim the crystal
on frequency within the limitations of the crystal’s trim
sensitivity and pullability. Figure 3-2 illustrates the
 2003 Microchip Technology Inc.
BYPASS CAPACITORS
APPLICATION CIRCUITS
General
FREQUENCY PLANNING
recommended
XTAL
) and intermediate frequency (f
XTAL EXAMPLE CIRCUIT
WITH OPTIONAL TRIM
CAPACITOR
DD
architecture
26
pins 8, 14, 17, 27 and 32
(OPTIONAL)
C TRIM
X1
for
with
general
a
single
purpose
if
). For
Preliminary
IF
effect the trim capacitor has on the receive frequency
for the rfRXD0420 at 433.92 MHz. Keep in mind that
this graph represents one example circuit and the
actual results depends on the crystal and PCB layout.
FIGURE 3-2:
Note that a 0 Ω resistor, in the lower left of the graph,
represents an infinite capacitance. This will be the
lowest frequency obtainable for the crystal and PCB
combination.
Calculation of the crystal frequency requires knowl-
edge of the receive frequency (f
frequency (f
designer in calculating the crystal frequency. Table 3-1
lists crystal frequencies for popular receive frequen-
cies. Table 3-2 lists crystal parameters required for
ordering crystals. For background information on
crystal selection see Application Note AN826, Crystal
Oscillator Basics and Crystal Selection for rfPIC
PICmicro
TABLE 3-1: CRYSTAL FREQUENCIES FOR
TABLE 3-2: CRYSTAL PARAMETERS
These values are for design guidance only.
434.10
434.05
434.00
433.95
433.90
433.85
433.80
433.75
Load Capacitance:
(1) Low-side injection (2) High-side injection
433.92 MHz
Frequency
Frequency:
Parameter
868.3 MHz
315 MHz
915 MHz
®
Receive
Mode:
ESR:
Devices.
if
rfRXD0420/0920
). Figure 3-3 is a worksheet to assist the
POPULAR RECEIVE
FREQUENCIES
RECEIVE FREQUENCY VS.
TRIM CAPACITANCE
rfRXD0420
rfRXD0920
Trim Capacitor (pF)
28.259375 MHz
20.35625 MHz
26.45125 MHz
(see Figure 3-1)
60 Ω Maximum
rf
Fundamental
26.8 MHz
Frequency
) and intermediate
15-20 pF
Crystal
DS70090A-page 9
Value
(1)
(2)
(1)
TM
(1)
and