ML7345 Family LSIs Hardware Design Manual
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6. Notes on selecting external parts (recommendations)
6.1. Anntenna
It is recommended to use an antenna with the specifications shown in Table 6.1.
Select an antenna with the best directive characteristics for your specific operating, environmental and
installation condition. Since antennas are affected by installation conditions such as GND, external factors should
always be taken into account.
It is recommended to ask the manufacturer of the selected antenna for installation details in relation to various
factors, including the shape and stray capacitance of the board to be used.
Table 6.1 Antenna
Frequency band
160~180MHz / 315~450MHz / 470~510MH
ｚ
/
868MHz / 920MHz band
VSWR
2.0MAX
Nominal Impedance
50Ω
6.2. Inductors
Use inductors with high Q. It is recommended to use LQW15AN series (manufactured by Murata Manufacturing
Co. Ltd) or equivalent.
6.3. Capacitors
Use capacitors with a CH (temperature compensating) or a B (high dielectric constant type) of temperature
characteristics. It is recommended to use capacitors of 0 ± 60 ppm/°C or less for areas that affect high frequency
characteristics. To realize lower power system it recommended to use low leak components because ML7345
has very low current consumption in sleep mode(0.4uA).
6.4. Resistors
Use resistors for which the resistance variation are small when the temperature changes.
7. Notes on board artworks (recommendations)
7.1. GND
About IC’s back side GND pad, the number of through-hole to board GND plane should be placed more than 12.
And drawing GND line width should be more wide as much as possible. Almost of L2 layer should be GND
plane for double-layered board.
