DEMO-ALM-3012 Datasheet, PDF (7/21 Pages) Broadcom Corporation. – GNSS LNA-Filter Front-End Module with optional Differential Outputs

Vdd = +2.7 V
Vsd
C3
L3
R1
C4
L4
1
C5
R2
7
L5 ₂
6
5
ALM-3012
3, 4, 8
Figure 3a. Application Circuit – Differential outputs
C2 RFout
L1
L2
C1 ^RFout+
Vdd = +2.7 V
Vsd
C3
L3
R1
C4
L4
1
C5
R2
7
L5 ₂
6
5
ALM-3012
3, 4, 8
Figure 3b. Application Circuit – Single-ended output
RFout (to be left open/grounded)
RFout+
Notes:
• The ALM-3012 can be operated with supply voltage (Vdd) from 1.8 V to 3.6 V. Vsd can operate from 1 V to Vdd.
• RF input match is achieved by a single series inductor, L5. It is used to match the module for best NF and S11.
• The differential outputs of the module are already pre-matched. Suggested matching components are shown as L1, L2, C1 and C2 for 100 ohm
differential load impedance. In practice, they may be tuned to match the RF GPS System on Chip (SoC) with a different input impedance, or an SoC
that is located a significant distance away from the module such that the phase shift of the transmission lines connecting the module and SoC are
not negligible.
• Best noise performance is obtained using high-Q wirewound inductors. This circuit demonstrates that low noise figures are obtainable with
standard 0402 chip inductors.
• C3 and C4 are bypass capacitors for RF and low frequency stability and linearity .
• Bias control is achieved by either varying the Vsd voltage with/ without R2, or fixing the Vsd voltage to Vdd and adjusting R2 for the desired
current.
• L3 and R1 isolates the demoboard from external disturbances during measurement. They are not needed in actual application. Likewise, C5
mitigate the effect of external noise pickup on the Vsd line. This component is not required in actual operation.
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