micrf507ymltr Micrel Semiconductor, micrf507ymltr Datasheet - Page 28

• Manufacturer Part Number: micrf507ymltr
• Description: 470mhz To 510mhz Low-power Fsk Transceiver With +10dbm Power Amplifier
• Manufacturer: Micrel Semiconductor

Transmitter
Power Amplifier
The maximum output power of the power amplifier (PA) is
approximately 10dBm with a 50Ω load. For maximum
output power, the load seen by the PA must be resistive.
Higher output power can be obtained by decreasing the
load impedance, but this will conflict with impedance
matching to the LNA.
The output power is programmable in seven levels by
means of the PA[2:0] field, with approximately 2.5dB
between steps; see Table 17. The power amplifier is
turned off when PA[2:0] = 000. Otherwise the PA is on and
output power increases with the value of the PA[2:0] field
and is maximum when PA[2:0] = 111.
March 2010
Micrel, Inc.
Field Name
Modulation
Mod_I
Mod_A
Mod_F
PA
PA_by
PA_By
PA2
0
0
0
0
1
1
1
1
0
1
Number
of bits
2
5
4
3
3
1
Power Amplifier Enabled
Power Amplifier bypassed, approx 20dB reduced output power.
Table 16. Register Bit Fields for Transmitter and VCO Modulation
PA1
Reg1[7:6]
Reg4[4:0]
Reg5[3:0]
Reg4[7:5]
Reg0[6:4]
Location
0
0
1
1
0
0
1
1
Reg2[4]
of bits
Table 17. Register Bit Fields for Power Amplifier
PA0
Description
Modulation selection
Modulator current setting
Modulator attenuator setting
Modulator filter setting
Power amplifier level
Bypass of PA stage on/off
0
1
0
1
0
1
0
1
State (approximate attenuation)
PA off
15dB attenuation
12.5dB attenuation
10dB attenuation
7.5dB attenuation
5dB attenuation
2.5dB attenuation
Max output
28
Setting PA_by=1 causes the PA to be bypassed and
output power to drop by ~22dB. It is still possible to control
the power with PA[2:0] bits.
The LC filter shown in Figure 18 reduces harmonic
emission when placed between the ANT pin and antenna.
Reference
Table 18
Table 17
Table 17
M9999-032210-B
MICRF507