Data Sheet

LJ1269HC
Rev1.0 Page 73 Web: www.ljelect.com
7. Application Information
7.1. Crystal Resonator Specification
Table 31 shows the crystal resonator specification for the crystal reference oscillator circuit of the LJ1269HC . This specification
covers the full range of operation of the LJ1269HC and is employed in the reference design.
Table 31 Crystal Specification
Symbol
Description
Conditions
Min
Typ
Max
Unit
FXOSC
XTAL
Frequency
26
-
32
MHz
RS
XTAL Serial
Resistance
-
30
140
ohms
C0
XTAL Shunt
Capacitance
-
2.8
7
pF
CLOAD
External Foot
Capacitance
On each pin
XTA and XTB
8
16
22
pF
Notes - the initial frequency tolerance, temperature stability and ageing performance should be chosen in accordance with the
target operating temperature range and the receiver bandwidth selected.
- the loading capacitance should be applied externally, and adapted to the actual Cload specification of the XTAL.
- A minimum XTAL frequency of 28 MHz is required to cover the 863-870 MHz band, 29 MHz for the 902-928 MHz band
7.2. Reset of the Module
A power-on reset of the LJ1269HC is triggered at power up. Additionally, a manual reset can be issued by controlling pin
RESET.
7.2.1. POR
If the application requires the disconnection of VDD from the LJ1269HC , despite of the extremely low Sleep Mode current, the
user should wait for 10 ms from of the end of the POR cycle before commencing communications over the SPI bus. Pin 6 (Reset)
should be left floating during the POR sequence.
Figure 38. POR Timing Diagram
Please note that any CLKOUT activity can also be used to detect that the Moduleis ready.
Sub GHz FSK/OOK Transceiver Module DATASHEET