MICRF104BM Micrel Inc, MICRF104BM Datasheet - Page 9

• Manufacturer Part Number: MICRF104BM
• Description: IC ASK TRANSMITTER UHF 14SOIC
• Manufacturer: Micrel Inc

Specifications of MICRF104BM

• Frequency: 300MHz ~ 470MHz
• Applications: RKE
• Modulation Or Protocol: ASK, OOK
• Data Rate - Maximum: 20 kbps
• Power - Output: -2dBm
• Current - Transmitting: 12mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 1.8 V ~ 4 V
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 14-SOIC (0.154", 3.90mm Width)
• Peak Reflow Compatible (260 C): No
• Supply Voltage Max: 4V
• Transceiver Type: RF Transmitter
• Data Rate Max: 20Kbps
• Leaded Process Compatible: No
• Mounting Type: Surface Mount
• No. Of Drivers: 1
• Supply Current: 35mA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -
• Memory Size: -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant, Contains lead / RoHS non-compliant

The value of the capacitor is calculated as 5.66pF.
Supply Bypassing
Correct supply bypassing is essential. A 4.7uF capacitor in
parallel with a 100pF capacitor is required and an additional
0.1 F capacitor in parallel is recommended.
The MICRF104 is susceptible to supply-line ripple, if supply
regulation is poor or bypassing is inadequate, spurs will be
evident in the transmit spectrum.
Transmit Power
The transmit power specified in this datasheet is normalized
to a 50Ohm load. The antenna efficiency will determine the
actual radiated power. Good antenna design will yield trans-
mit power in the range of 67dB V/m to 80dB V/m at 3 meters.
The PC pin on the MICRF104 is used to set the transmit
power. The differential voltage on the output of the PA (power
amplifier) is proportional to the voltage at the PC pin.
November 8, 2001
MICRF104
L = 45.1nH
9
If the PC pin voltage rises above 0.4 V the output power
becomes current limited. At this point, further increase in the
PC pin voltage will not increase the RF output power in the
antenna pins. Low power consumption is achieved by de-
creasing the voltage in the PC pin, also reducing the RF
output power and maximum range.
Output Blanking
When the device is first powered up or after a momentary loss
of power the output is automatically blanked (disabled). This
feature ensures RF transmission only occurs under con-
trolled conditions when the synthesizer is fully operational,
preventing unintentional transmission at an undesired fre-
quency. Output blanking is key to guaranteeing compliance
with UHF regulations by ensuring transmission only occurs in
the intended frequency band.
MICRF104
Micrel