SWRS325 December 2024 AWRL6844
ADVANCE INFORMATION
1.0V RF LDO require two decoupling capacitors with typical values of 10uF and 22uF.
The parasitic offered by different portion of the output path is illustrated in Figure 7-4. As shown in figure, the output path can be divided into four portions:
Ball to first capacitor: “RT1” and “LT1” are the parasitic resistance and inductance offered by the ball to the first capacitor lead.
Along the first capacitor: “ESL1” and “ESR1” are the effective series inductance and resistance of the first decoupling capacitor. “RT2” and “LT2” are the ground trace resistance and inductance respectively of the first capacitor ground trace.
First capacitor lead to second capacitor lead: “RTC2C” and “LTC2C” are the resistance and inductance of the trace between two capacitors.
Along the second capacitor: “ESL2” and “ESR2” are the effective series inductance and resistance of the second decoupling capacitor. “RT2” and “LT2” are the ground trace resistance and inductance respectively of the second capacitor ground trace.
D5,D6 and D7 BGA balls to K5 BGA ball “RT3” and “LT3” are the parasitic resistance and inductance offered from D5,D6 and D7 BGA balls to K5 BGA ball.
Recommended to avoid placing any capacitors on K5 ball.
Both the capacitors (10uF and 22uF) are recommended to be placed close to the respective VDDA_10RF BGA ball.
Place the output decoupling capacitors of 1.0V RF LDO on the same layer of PCB (either on top or on the bottom layer of PCB).