For SPF5043Z, the typical operating current at 3V is 25mA.
For QPA4563C, the typical current at 3V is 46mA.
Could the operating current of both devices be adjusted to around 10mA?
I assume that a resistor connected in series with a power supply can achieve this.
It there a plot or table for selecting bias resistor?
If the current drop to 10-15mA, how does it affect the Gain and P1dB?
Hi, this could be achieved by adding a shunt resistor from the RF input to ground. This shifts the bias point of the device. This has been tried on the SPF5043Z (see attached draft AN)
SPF5043Z Reduced Current (AN-Draft).pdf (421.8 KB)
, but not on the QPA4563C. If you need a low current LNA/gain block you could also look at the QPA0363A, QPA0163L, or SGL0622Z.
Hi, Chris,
Thanks for reply.
For QPA0163L is not recommended for new design.
For QPA0363A and SGL0622Z, the operating current is fine. However, the max current is below our requirement, which is at least 35mA. And P1dB of these 2 devices will be a concern for our application. OP1dB is approx. 12dBm.
If you could refer to datasheet of QPA4563C,
Schematic on page 3. R1 is 0 ohm, so, Vd on pin 6 is close to Vs=3V, which set the Id=48mA.
According to plot of Current vs Voltage on page 4, QPA4563C could work at 10-15mA, if Vs is around 2V.
Could it be achieved by adjusting R1 to set Vd on Pin 6 is close to 2V? If so, will OP1dB degrade? Do you have a plot/table of Id vs OP1dB?
Yes you could use a larger bias resistor R1 to set QPA4563C current lower. P1dB will degrade when running at 2V. There is no test data at 2V unfortunately, except current.