TRC105 RFM, TRC105 Datasheet - Page 46

• Manufacturer Part Number: TRC105
• Description: IC TXRX 300MHZ-510MHZ 32TQFN
• Manufacturer: RFM

Specifications of TRC105

• Frequency: 300MHz ~ 510MHz
• Data Rate - Maximum: 200kbps
• Modulation Or Protocol: FSK, OOK
• Applications: General Purpose
• Power - Output: 13dBm
• Sensitivity: -112dBm
• Voltage - Supply: 2.1 V ~ 3.6 V
• Current - Receiving: 3mA
• Current - Transmitting: 30mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFN
• Wireless Frequency: 300 MHz to 510 MHz
• Output Power: 13 dBm
• Operating Supply Voltage: 2.1 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Maximum Supply Current: 1.7 mA
• Minimum Operating Temperature: - 40 C
• Modulation: FSK, OOK
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 583-1159-2

6.1.2 Voltage Controlled Oscillator Component Values
The TRC105 VCO requires four external components for operation, two tank circuit inductors and two power sup-
ply decoupling capacitors. It is important to use high-Q chip inductors in the tank circuit. This assures low phase
noise VCO operation and minimum interference from signals near the TRC105’s operating frequency due
operating band and the PCB layout. Typical values are given in Table 58 (location of L5 & L6 shown in Figure 2):
The tank circuit inductors should be mounted close to their IC pads with the long axis of the coil at right angles to
the edge of the IC where the pads are located. The decoupling capacitors should be positioned on each side of
the tank circuit inductors. Other RF chokes and coils should be spaced somewhat away from the tank inductors
and positioned at right angles to minimize coupling.
VCO frequency centering is checked by looking at the voltage between pads 6 and 7. The voltage should be 150
±50 mV when the TRC105 is in transmit mode at a frequency near the center of the operating band and subband.
VCO frequency centering can be adjusted by changing the value of the tuning inductors and/or adjusting the VCO
trim bits 1 and 2 in configuration register MCFG05. The trim bits adjust the tuning voltage in increments of about
60 mV. Increasing the value of the tuning inductors increases the tuning voltage between pads 6 and 7.
6.2 Determining Configuration Values for FSK Modulation
6.2.1 Bit Rate Related FSK Configuration Values
The TRC105 supports RF bit rates (data rates) from 1.5625 to 200 kb/s for FSK modulation. There are several
considerations in choosing a bit rate. The sensitivity of the TRC105 decreases with increasing data rate. A bit rate
should be chosen that is adequate but not higher than the application requires. The exception to this rule is when
the TRC105 is operated as a frequency hopping spread spectrum transceiver in a noisy or crowded band. Run-
ning at a higher bit rate will allow a higher channel hopping rate, which provides more robust operation in a
crowded band in tradeoff for less range under quiet band conditions.
The TRC105 RF bit rate is set by the value of the bytes loaded in MCFG03 and MCFG04. For the standard crys-
tal frequency of 12.8 MHz:
Where BR is the bit rate in kb/s, F
MCFG04. This bit rate value supports both the data and clock recovery circuit in the receiver and the bit rate
clocking in the transmitter modulator. Using the default value of D and solving the equation above for C:
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to phase noise reciprocal mixing. The two tank circuit inductors have the same value which depends on the VCO
BR = 12800/(2*(C+1)*(D + 1)), with C in the range of 0 to 255, and D = 31 (default value)
C = (12800 - 64*BR)/64*BR
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XTAL
300-330 MHz
330-365 MHz
365-400 MHz
400-440 MHz
440-470 MHz
470-510 MHz
the crystal frequency in kHz, C the value in MCFG03, and D the value in
Band
Technical support +1.800.704.6079
Table 58
L5 & L6
39 nH
27 nH
27 nH
22 nH
15 nH
TBD
Tolerance
±5%
±5%
±5%
±5%
±5%
±5%
TRC105 - 11/01/10
Page 46 of 66