UM10473 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
User manual Rev. 01. — 29 August 2011 4 of 19
NXP Semiconductors
UM10473
OL2300 Demo board user manual
2. Evaluation board schematic
The schematic of the evaluation board is shown in Figure 1.
The 125 kHz transponder antenna of the PCF7941 and the three switches are not
mounted.
The transmitter section of the board is isolated by removing the following six jumpers:
TX_SUPPLY, EN, SCK, SDIO, CKOUT, SDO. The jumpers allow the following:
• evaluation of the onboard OL2300 IC in combination with another µC
• monitoring of the SPI connection
• current measurements
The crystal which is connected to the oscillator pins of OL2300 is an NDK NX5032GA. A
frequency of 13.28963 MHz is chosen to cover the 434 MHz band as well as the 868 MHz
and the 915 MHz bands. However, for the 868 MHz and 915 MHz band, the matching
network must be adapted accordingly.
In the 315 MHz version, the crystal frequency is 18.37036 MHz. The reference clock
frequency is divided by two to keep the PLL frequency below the specified maximum of
920 MHz. To achieve this frequency limitation, the internal XTAL clock divider is set to
XOSL = 1.
The UHF matching network is adapted to transform the 50 terminated output
impedance of connector X2 to the optimal impedance of the RF power amplifier. This is
done in a way to attain the highest possible output power in power mode III (PAM=3) with
a harmonic suppression of at least 50 dBc.
