Datasheet
MRF49XA
DS70590C-page 12 Preliminary © 2009-2011 Microchip Technology Inc.
9 RFXTL/EXTREF Analog Input RF Crystal: This pin is connected to a 10 MHz series crystal
or to an external oscillator reference. The crystal is used as a
reference for the PLL which generates the local oscillator
frequency. It is possible to “pull” the crystal to the accurate
frequency by changing the load capacitor value.
External Reference Input: An external reference input, such
as an oscillator, can be connected as a reference source.
Connect the oscillator through a 0.01 μF capacitor.
10 RESET
Digital Input/Output Active-low hardware pin. This pin has an open-drain Reset
output with internal pull-up and input buffer. Refer to
Section 3.1, Reset for more details.
11 Vss Ground Ground reference.
12 RFP RF Input/Output Differential RF input/output (+).
13 RFN RF Input/Output Differential RF input/output (-).
14 V
DD Power RF power supply. Bypass with a capacitor close to the pin.
See Section 2.1, Power and Ground Pins for more details.
15 RSSIO Analog Input/Output Received Signal Strength Indicator Output: The analog
RSSI output is used to determine the signal strength. The
response and settling time depends on the external filter
capacitor. Typically, a 4-10 nF capacitor provides optimum
response time for most applications.
16 INT
/DIO Digital Input/Output Interrupt: This pin can be configured as an active-low
external interrupt to the device. If a logic ‘0’ is applied to this
pin, it causes the IRO
pin to toggle, signaling an interrupt to
the external microcontroller. The source of interrupt can be
determined by reading the first four bits of STSREG (see
Ta ble 2-4). This pin can be used to wake-up the device from
Sleep.
Data Indicator Output: This pin can be configured to
indicate valid data based on the actual internal settings.
TABLE 2-1: PIN DESCRIPTION (CONTINUED)
Pin Symbol Type Description