MRF49XA-I/ST Microchip Technology, MRF49XA-I/ST Datasheet - Page 50

• Manufacturer Part Number: MRF49XA-I/ST
• Description: IC RF TXRX 433/868/915 16-TSSOP
• Manufacturer: Microchip Technology

Specifications of MRF49XA-I/ST

• Package / Case: 16-TSSOP
• Frequency: 433MHz, 868MHz, 915MHz
• Data Rate - Maximum: 256kbps
• Modulation Or Protocol: FHSS, FSK
• Applications: Home / Industrial Automation, Remote Access, Security Alarms
• Power - Output: 7dbm
• Sensitivity: -110dBm
• Voltage - Supply: 2.2 V ~ 3.8 V
• Current - Receiving: 11mA
• Current - Transmitting: 15mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Number Of Receivers: 1
• Number Of Transmitters: 2
• Wireless Frequency: 433 MHz to 915 MHz
• Output Power: + 7 dBm
• Operating Supply Voltage: 2.5 V, 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Modulation: FHSS, FSK
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 579-MRF49XA-1/ST

3.6
The crystal oscillator of MRF49XA requires a 10 MHz
Parallel mode crystal. The circuit contains an inte-
grated load capacitor in order to minimize the external
component count. The internal load capacitance value
is programmable from 8.5 pF to 16 pF in 0.5 pF steps.
With appropriate PCB layout, the total load capacitance
value can be 10 pF to 20 pF, so a variety of crystal
types can be used.
When the total load capacitance is not more than 20 pF,
and a worst case 7 pF Shunt Capacitance (C
expected for the crystal, the oscillator is able to start-up
with any crystal having less than 100Ω Equivalent
Series Loss Resistance (ESR). However, the low C
and ESR values ensure the faster oscillator start-up.
FIGURE 3-5:
DS70590B-page 48
MRF49XA
Crystal Selection Guidelines
Bit Rate: 2.4 kbps
Bit Rate: 9.6 kbps
Bit Rate: 38.4 kbps
Bit Rate: 115.2 kbps
433 MHz
868 MHz
915 MHz
433 MHz
868 MHz
915 MHz
433 MHz
868 MHz
915 MHz
433 MHz
868 MHz
915 MHz
Do Not Use
Do Not Use
Do Not Use
MAXIMUM CRYSTAL TOLERANCES INCLUDING TEMPERATURE AND AGING (ppm)
Do Not Use
Do Not Use
Do Not Use
105
30
20
10
10
30
15
30
8
8
Do Not Use
Do Not Use
45
30
20
15
45
30
15
15
45
5
3
3
120
3
S
) value is
Preliminary
Deviation [± kHz]
Deviation [± kHz]
Deviation [± kHz]
Deviation [± kHz]
60
50
25
25
60
50
25
25
60
20
10
10
S
135
20
10
10
The Crystal Frequency (f
the PLL, which generates the Local Oscillator Fre-
quency (f
The accuracy requirements for production tolerance,
temperature drift and aging can thus be determined from
the maximum allowable local oscillator frequency error.
Whenever a low-frequency error is essential for the
application, it is possible to “pull” the crystal to the accu-
rate frequency by changing the load capacitor value.
The widest pulling range can be achieved if the nominal
required load capacitance of the crystal is in the “mid-
range”; for example, 16 pF. The “pull-ability” of the
crystal is defined by its Motional Capacitance (C
shunt capacitance.
75
70
30
30
75
70
30
30
75
30
20
15
150
30
20
15
LO
). Therefore, f
90
90
40
40
90
80
40
40
90
50
25
25
165
50
25
25
© 2009 Microchip Technology Inc.
LO
ref
105
100
105
100
105
50
50
50
50
75
30
30
180
) is used as the reference of
70
35
30
is directly proportional to f
120
100
120
100
120
195
60
50
60
50
75
40
40
80
45
40
m
) and
ref
.