mrf89xa Microchip Technology Inc., mrf89xa Datasheet - Page 14

• Manufacturer Part Number: mrf89xa
• Description: Ultra-low Power, Integrated Ism Band Sub-ghz Transceiver
• Manufacturer: Microchip Technology Inc.

2.1
To
characteristics over a wide supply range, the
MRF89XA is internally voltage regulated. This internal
regulated power supply block structure is illustrated in
Figure 2-2.
The power supply bypassing is essential for better
handling of signal surges and noise in the power line.
To ensure correct operation of the regulator circuit, the
decoupling capacitor connection (shown in Figure 2-2)
is recommended. These decoupling components are
recommended for any design. The power supply block
generates four regulated supplies for the analog,
digital, VCO and the PLL blocks to reduce the voltages
for their specific requirements. However, Power-on
Reset (POR), Configuration registers and the SPI use
the V
FIGURE 2-2:
TABLE 2-2:
DS70622B-page 14
MRF89XA
POR, SPI and Configuration Registers
Regulated Supply (V
Analog
Digital
VCO
PA
DD
provide
supply given to the MRF89XA.
Power Supply and Ground Block
Pins
Biasing:
- SPI
- Config. Registers
- POR
Blocks
stable
POWER SUPPLY PIN DETAILS
INTS
POWER SUPPLY BLOCK DIAGRAM
)
sensitivity
V
BAT
1 µF
Analog Regulator
Y5V
Biasing Analog
Blocks
1.0 V
and
AVRS
Pin 27
Biasing Through
linearity
Y5V
1 µF
V
V
V
Preliminary
0.22 µF
V
V
V
INTS
INTS
INTS
Digital Regulator
X7R
Internal Regulator
DD
DD
DD
Biasing Digital
Blocks
1.4 V
1.0 V
DVRS
Pin 28
External Supply
V
The large value decoupling capacitors should be
placed at the PCB power input. The smaller value
decoupling capacitors should be placed at every power
point of the device and at bias points for the RF port.
Poor bypassing can lead to conducted interference,
which can cause noise and spurious signals to couple
into the RF sections, thereby significantly reducing the
performance.
It is recommended that the V
capacitors to ensure sufficient bypass and decoupling.
However, based on the selected carrier frequency, the
bypass capacitor values vary. The trace length (V
to bypass capacitors) should be made as short as
possible.
DD
2.1 – 3.6V
– Pin 26
0.1 µF
Associated Pins
X7R
VCO Regulator
V
Biasing:
- VCO Circuit
- Ext. VCO Tank
INTS
VCORS
0.85 V
DVRS
AVRS
PARS
V
V
DD
DD
VCORS
Pin 3
© 2010 Microchip Technology Inc.
0.047 µF
Biasing:
- PA Driver
- Ext. PA Choke
X7R
PA Regulator
DD
1.80 V
Regulated Voltage
pin have two bypass
Pin 29
PARS
(in Volts)
2.1-3.6
0.85
1.4
1.0
1.0
1.8
DD
pin