RF2364
Application Notes
Power Down Pin Resistor
The Power Down pin (pin 3) of the RF2364 3V Low Noise Amplifier should be maintained at 2.7V to 2.9V for proper
operation. This voltage range ensures the correct bias current will be present at the Power Down pin of the device. How-
ever, an external series resistor may be used to allow various operating voltages at this pin (see R1 in Application Sche-
matics). The required value for this resistor may be roughly calculated by using the operating input voltage to the Power
Down pin, the desired voltage at the device, and the typical current consumption for the Power Down pin, along with
Ohms law.
For example, assume the design will supply 3.3V to the Power Down pin of the device, but the biasing circuitry internal to
the RF2364 requires 2.8V, and the power down bias current is known to typically be 5.5mA, then the required value from
R1 would be found from:
3.3V – 2.8V
----------------------------
= 90.9Ω
5.5mA
4-360
Rev A5 020827
RFMD [ RF MICRO DEVICES ]
