Preliminary
8-48
RF2469
Rev A5 010717
8
Low Current Configuration
External resistors can set different bias currents for LNA1 (pin 3), LNA2 (pin 4, also called the preamplifier of the mixer),
and mixer (pin 17). Customers have the flexibility to choose the most suitable bias current, and therefore the perfor-
mance, of the IC. The charts on the following page reflect different bias currents for the RF2469.
The currents were calculated using the following equations.
LNA1 current (R1)= Total Current (LNA1= EN =1, LNA2 =0)-Total Current (EN= 1, LNA1= LNA2=0)+1.6
1.6 is the bypass current of LNA1
Mixer/LNA2 current (R2)=Total Current (LNA1= 0, LNA2 =EN =1)-Total Current (LNA1 =LNA2= 0, EN= 1)+1.4+ 10.2
1.4 is the bypass current of LNA2; 10.2 is the mixer (LO buffer included)
Mixer Only current (R5)=Total Current (EN =LNA2= 1, LNA1= 0)-4.5
4.5 is the bypass current of the LNA1 (1.6mA)+ LNA2 high mode current (2.9mA)
RFMD chose a low current configuration of the RF2469, by using R1= 3k
Ω, R2=3.6kΩ,and R5=1kΩ in the evaluation
board, and the following lab results over temperature were obtained.
LNA1 High Mode
Temp
(°C)
Frequency
(MHz)
PIN
(dBm)
VCC
(VDC)
Gain
(dB)
IIP3
(dBm)
Noise Figure
(dB)
Total
Current
-30
2140
-25
2.78
+7.97
-3.78
+1.72
+11.33
+25
2140
-25
2.78
+8.81
+2.32
+1.95
+12.36
+85
2140
-25
2.78
+9.70
+7.71
+2.37
+16.45
Total Current (mA) is when LNA1BYP=LNA2BYP2=EN =1.
Mixer/LNA2 BYP High Mode
Temp
(°C)
Frequency
(MHz)
PIN
(dBm)
LO Frequency
(MHz)
PIN LO
(dBm)
VCC
(VDC)
Gain
(dB)
IIP3
(dBm)
Noise Figure
(dB)
-30
2140
-25
2330
-10
2.78
+18.73
-8.16
+3.98
+25
2140
-25
2330
-10
2.78
+17.74
+5.13
+4.54
+85
2140
-25
2330
-10
2.78
+16.67
-3.66
+5.19
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