MICRF104 データシートの表示（PDF） - Micrel
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MICRF104 Datasheet PDF : 10 Pages
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MICRF104
Functional Diagram
VDDPWR
EN
Oscillator
Thermal
Shutdown
Enable
Logic
Driver
Micrel
SW
VSS
Error
Amplifier
1.2V
Bandgap
Reference
5V
DC/DC Converter
STBY
VDDRF
VDD
Reference
Bias
(10)
TX
Bias
Control
(9)
Power
Amp
(8)
ASK
ANTP
ANTM
PC
Phase
Detector
(2)
REF.OSC
Reference
Oscillator (1)
Prescaler
Divide
by 32
(5)
VCO (4)
(3)
Buffer
(6a)
Buffer
(6b)
Antenna
Tuning
Control
(7)
Varactor
Device
(11)
RF Transmitter
VSS
Figure 2. MICRF104 Block Diagram (RF Circuit)
Functional Description
The block diagram illustrates the basic structure of the RF
portion of the MICRF104. Identified in the figure are the
principal functional blocks of the IC, namely the (1, 2, 3, 4, 5)
UHF Synthesizer, (6a/b) Buffer, (7) Antenna tuner, (8) Power
amplifier, (9) TX bias control, (10) Reference bias and (11)
Process tuner.
The UHF synthesizer generates the carrier frequency with
quadrature outputs. The in-phase signal (I) is used to drive
the PA and the quadrature signal (Q) is used to compare the
antenna signal phase for antenna tuning purpose.
The Antenna tuner block senses the phase of the transmit
signal at the antenna port and controls the varactor capacitor
to tune the antenna.
The Power control unit senses the antenna signal and con-
trols the PA bias current to regulate the antenna signal to the
transmit power.
The Process tune circuit generates process independent
bias currents for different blocks.
A PCB antenna loop coupled with a resonator and a resistor
divider network are all the components required to construct
MICRF104
6
November 8, 2001
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