Datasheet

 2014 Microchip Technology Inc. Advance Information DS70005173A-page 7
MRF24J40MD/ME
1.4 Operation
The MRF24J40MD/ME module is based on the
Microchip Technology MRF24J40 2.4 GHz IEEE
802.15.4 RF Transceiver IC. Serial communication and
configuration are documented in the “MRF24J40 Data
Sheet” (DS39776).
This section emphasizes operational settings that are
unique to the MRF24J40MD/ME module design that
must be followed for proper operation.
1.4.1 PA/LNA CONTROL
Operation of the PA U6 and LNA U1 is controlled by the
MRF24J40 internal RF state machine through RF
switches, U3 and U4, and the GPIO0, GPIO1 and GPIO2
pins on the MRF24J40. Figure 1-6 shows the PA/LNA
block diagram. Figure 2-5 is the schematic diagram for
the module.
The internal RF state machine is configured for the PA/
LNA Mode by setting TESTMODE (0x22<2:0>) = 111.
Pins GPIO0, GPIO1 and GPIO2 control the RF
switches, PA and LNA automatically when the
MRF24J40 receives and transmits data.
FIGURE 1-6: PA/LNA BLOCK DIAGRAM
Note: A complete explanation of the operation of
the PA/LNA control is documented in the
“MRF24J40 Data Sheet” (DS39776),
Section 4.2 “External PA/LNA Control”.
MRF24J40
GPIO1
GPIO2
U.FL
Connector
(ME)
Balun
RFP
RFN
PA
SST12LP17E
LNA
PA
RF Switch
RF3023TR7
RF Switch
RF3023TR7
LNA
SST12LN01
V2 V1 V2 V1
GPIO0
PA_ON
TX
RX
BPF
PCB
Antenna
(MD)