MRF24J40MA Datasheet, PDF (11/30 Pages) Microchip Technology – 2.4 GHz IEEE Std. 802.15.4 RF Transceiver Module

2.0 CIRCUIT DESCRIPTION
The MRF24J40MA is a complete 2.4 GHz IEEE Std.
802.15.4™ compliant surface mount module with
integrated crystal, internal voltage regulator, matching
circuitry and PCB antenna. The MRF24J40MA module
interfaces to many popular Microchip PIC micro-
controllers via a 4-wire serial SPI interface, interrupt,
wake, Reset, power and ground. Data communications
with the MRF24J40MA module is documented in the
“MRF24J40 IEEE 802.15.4™ 2.4 GHz RF Transceiver
Data Sheet” (DS39776). Refer to the MRF24J40 data
sheet for specific serial interface protocol and register
definitions.
MRF24J40MA
2.1 Schematic
A schematic diagram of the module is shown in
Figure 2-1 and the Bill of Materials (BOM) is shown in
Table 2-1.
The MRF24J40MA module is based on the Microchip
Technology MRF24J40 IEEE 802.15.4™ 2.4 GHz RF
Transceiver IC. The serial I/O (SCK, SDI, SDO and
CS), RESET, WAKE, INT and CLKOUT pins are
brought out to the module pins. The SDO signal is
tri-state buffered by IC2 to solve a silicon errata where
the SDO signal does not release to a high-impedance
state after the CS pin returns to its inactive state.
Crystal X1 is a 20 MHz crystal with a frequency
tolerance of ±20 ppm @ 25°C to meet the IEEE Std.
802.15.4 symbol rate tolerance of ±40 ppm. A balun is
formed by components: L1, L3, C2 and C14. L2 is an
RF choke and pull-up for the RFP and RFN pins on the
MRF24J40. C15 is a DC block capacitor. A low-pass
filter is formed by components: L4, C16 and C17. The
remaining capacitors provide RF and digital bypass.
© 2008 Microchip Technology Inc.
Advance Information
DS70329A-page 9