ADF7011 Просмотр технического описания (PDF) - Analog Devices

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ADF7011

High Performance ISM Band ASK/FSK/GFSK Transmitter IC

Analog Devices 

ADF7011

APPLICATION EXAMPLES

Application Example 1

Operating Frequency 433.92 MHz

Output Power

+10 dBm

Current Consumption <30 mA

Modulation

ASK/FSK

This system should be set up as shown Figure 15. The spurious

levels using a crystal frequency of 4 MHz are sufficiently low so

as not to require any band-pass filtering of the output. However,

2 dB of attenuation will be required at 541.50 MHz in order

to comply with ES-300-220. This can be achieved easily with

the harmonic filter. The harmonic filter can be designed at the

output of the matching network with 50 Ω impedance, or it

may be integrated into the matching network. The ADF7011

will allow multichannel operation in the 433 MHz band. If

FSK modulation is used, the BW should be about five times

the data rate. In the case of ASK modulation, a minimum

data rate of 1 MHz should be used to minimize the occupied

spectrum. The free design tool, ADIsimPLL, should be down-

loaded from www.analog.com/pll to ascertain the values of the

filter components.

Application Example 2

Operating Frequency

Output Power

Current Consumption

Modulation

868.3 MHz

+3 dBm

<25 mA

ASK/FSK

In order to meet the ETSI requirement EN300-220, the maxi-

mum output power without using a filter is +3 dBm. This is

because the spurious levels scale with output power. Utilizing a

PFD frequency of 4.42 MHz will reduce the level of the refer-

ence spurs, and place the first spur in a –36 dBm bin, 4.4 MHz

below the carrier. ADIsimPLL should be used to design the

loop filter, aiming for a loop bandwidth of five times the data

rate for FSK. ASK modulation requires a loop BW > 1 MHz to

minimize spectral occupancy.

Application Example 3

Operating Frequency

Output Power

Current Consumption

Modulation

868.3 MHz

+10 dBm

<40 mA

ASK/FSK

In order to meet the ETSI requirements at +10 dBm output

power, it is necessary to add an inexpensive GigaFILT from

Murata at the output. This will reduce the prescaler and refer-

ence spurious levels to –54 dBm, and also reduce the harmonic

levels to within the –30 dBm level. Given that the insertion

loss is 2 dB, it is necessary to use the maximum +12 dBm

power from the ADF7011 to achieve an antenna port level of

+10 dBm. The filter layout is important to ensure that there is

margin in the output spectrum; filter data sheet guidelines

should be adhered to.

–20–

REV. 0

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