RFHCS362GT-I/SO Microchip Technology, RFHCS362GT-I/SO Datasheet - Page 29

• Manufacturer Part Number: RFHCS362GT-I/SO
• Description: IC CODE HOPPNG ENCDR W/RF 18SOIC
• Manufacturer: Microchip Technology

Specifications of RFHCS362GT-I/SO

• Frequency: 310MHz ~ 440MHz
• Applications: Automotive, Building Access, Garage Openers
• Modulation Or Protocol: ASK, FSK
• Data Rate - Maximum: 3.3 kbps
• Power - Output: -12dBm ~ 2dBm
• Current - Transmitting: 11.5mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2.2 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 18-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -

6.0
6.1
The transmitter is a fully integrated UHF ASK/FSK
transmitter consisting of crystal oscillator, Phase-
Locked Loop (PLL), open-collector differential-output
Power Amplifier (PA), and mode control logic. External
components consist of bypass capacitors, crystal, and
PLL loop filter. The rfHCS362G is capable of Amplitude
Shift Keying (ASK) modulation. The rfHCS362F is
capable of ASK or Frequency Shift Keying (FSK) mod-
ulation by employing an internal FSK switch to pull the
transmitter crystal via a second load capacitor.
Figure 2-1 shows the internal structure of the transmit-
ter. Transmitter connections are independent from the
encoder to provide for maximum design flexibility.
Example application circuits for ASK or FSK modula-
tion are presented in Section 1.2.
The rfHCS362G/362F are radio frequency (RF) emit-
ting devices. Wireless RF devices are governed by a
country’s regulating agency. For example, in the United
States it is the Federal Communications Committee
(FCC) and in Europe it is the European Conference of
Postal
(CEPT). It is the responsibility of the designer to ensure
that their end product conforms to rules and regulations
of the country of use and/or sale.
TABLE 6-1:
RF devices require correct board level implementa-
tion in order to meet regulatory requirements. Layout
considerations are listed at the end of each subsec-
tion. It is best to place a ground plane on the PCB to
reduce radio frequency emissions and cross talk.
f
C
C
ESR
These values are for design guidance only.
XTAL
2002 Microchip Technology Inc.
L
O
Sym
UHF ASK/FSK TRANSMITTER
Transmitter Operation
and
Crystal Frequency
Load Capacitance
Shunt Capacitance
Equivalent Series Resistance
Telecommunications
CRYSTAL PARAMETERS
Characteristic
Administrations
9.69
Min
10
—
—
Preliminary
Max
15
15
60
7
6.2
Pins V
respectively to the transmitter. These power pins are
separate from power supply pins V
encoder.
6.3
The transmitter crystal oscillator is a Colpitts oscillator
that provides the reference frequency to the PLL. It is
independent from the encoder oscillator. An external
crystal or AC coupled reference signal is connected to
the XTAL pin. The transmit frequency is fixed and
determined by the crystal frequency according to the
formula:
Due to the flexible selection of transmit frequency, the
resulting crystal frequency may not be a standard off-
the-shelf value. Therefore, for some carrier frequencies
the designer will have to consult a crystal manufacturer
and have a custom crystal manufactured. Crystal
parameters are listed in Table 6-1. For background
information on crystal selection see Application Note
AN588, PICmicro
Guide, and AN826 Crystal Oscillator Basics and Crys-
tal Selection for rfPIC™ and PICmicro
The crystal oscillator start time (t
Table 10-7, Transmitter AC Characteristics.
Layout Considerations - Provide low impedance
power and ground traces to minimize spurious emis-
sions. A two-sided PCB with a ground plane on the
bottom layer is highly recommended. Separate
bypass capacitors should be connected as close as
possible to each of the supply pins V
Connect V
separate PCB vias. Do not share a PCB via with mul-
tiple ground traces.
Units
MHz
pF
pF
DDRF
Supply Voltage (V
Crystal Oscillator
rfHCS362G/362F
SS
and V
Parallel Resonant Mode
and V
f
®
transmit
SSRF
Microcontroller Oscillator Design
Conditions
SSRF
supply power and ground
to the ground plane using
f
XTAL
DDRF
DD
32
DS41189A-page 29
®
on
, V
DD
and V
Devices.
) is listed in
SSRF
and V
SS
)
DDRF
to the
.