MRF24J40-I/ML Microchip Technology, MRF24J40-I/ML Datasheet - Page 138

• Manufacturer Part Number: MRF24J40-I/ML
• Description: IC TXRX IEEE/ZIGBEE 2.4GHZ 40QFN
• Manufacturer: Microchip Technology

Specifications of MRF24J40-I/ML

• Package / Case: 40-QFN
• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: 802.15.4
• Applications: ISM, ZigBee™
• Power - Output: 0dBm
• Sensitivity: -95dBm
• Voltage - Supply: 2.4 V ~ 3.6 V
• Current - Receiving: 18mA
• Current - Transmitting: 18mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Number Of Receivers: 1
• Number Of Transmitters: 1
• Wireless Frequency: 2.4 GHz
• Interface Type: 4 Wire SPI
• Noise Figure: 8 dB
• Output Power: + 0 dBm
• Operating Supply Voltage: 2.5 V, 3.3 V
• Maximum Operating Temperature: 85 C
• Mounting Style: SMD/SMT
• Maximum Supply Current: 22 mA
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4.3
The following guidelines are intended to aid users in
high-frequency PCB layout design.
FIGURE 4-5:
• It is important to keep the original PCB thickness
• The first layer width of a 50 Ω characteristic
• Avoid having microstrip lines longer than 2.5 cm,
• Except for the antenna layout, avoid sharp
• Digital lines by definition are prone to be very
DS39776C-page 138
MRF24J40
since any change will affect antenna performance
(see total thickness of dielectric) or microstrip
lines characteristic impedance.
impedance microstrip line is 12 mils.
since that line might get very close to a quarter
wave length of the working frequency of the board
which is 3.0 cm, and start behaving as an
antenna.
corners since they can act as an antenna. Round
corners will eliminate possible future EMI
problems.
noisy when handling periodic waveforms and fast
clock/switching rates. Avoid laying out a RF signal
close to any digital lines.
PCB Layout Design
Note:
FOUR BASIC COPPER FR4 LAYERS
Care should be taken with all ground lines to prevent breakage.
Preliminary
Signal Layout, Thickness = 1.8 mils
Dielectric ε = 4.5, Thickness = 7 mils
RF Ground, Thickness = 1.2 mils
Dielectric ε = 4.5, Thickness = 19 mils
Power Line Routing, Thickness = 1.2 mils
Dielectric ε = 4.5, Thickness = 7 mils
Ground, Thickness = 1.8 mils
The printed circuit board is comprised of four basic FR4
layers: signal layout, RF ground, power line routing and
ground (see Figure 4-5). The guidelines will explain the
requirements of these layers.
• A via filled ground patch underneath the IC
• A power supply must be distributed to each pin in
• Thorough decoupling on each power pin is
• Passive components (inductors) must be in the
transceiver is mandatory.
a star topology and low-ESR capacitors must be
placed at each pin for proper decoupling noise.
beneficial for reducing in-band transceiver noise,
particularly when this noise degrades perfor-
mance. Usually, low value caps (27-47 pF)
combined with large value caps (100 nF) will
cover a large spectrum of frequency.
high-frequency category and the SRF
(Self-Resonant Frequency) should be at least two
times higher than the operating frequency.
© 2010 Microchip Technology Inc.