UM-B-074
DA1468x Range Extender Daughterboard
User Manual
Revision 1.1
17-Apr-2018
CFR0012
24 of 60
© 2018 Dialog Semiconductor
8
Crystals
DA14680/681 SoC has two Digitally Controlled Crystal Oscillators (DXCO) one at 16 MHz
(XTAL16M) and a second at 32.768 kHz (XTAL32K). The 32.738 kHz oscillator is the Low Power
(LP) clock, which is used for the HW FSM during power-up/wake-up, for the TIMER1 upon which is
based the system timer and it is used in Extended/Deep Sleep low power modes of the DA1468x.
The 32.768 kHz oscillator has no trimming capabilities. The 16 MHz oscillator can be trimmed.
The crystals used are specified in
Table 13
and Table 14:
Table 13: Y1 16 MHz Crystal Characteristics
Reference Designator
Value
Part Number
7M-16.000MEEQ-T
Frequency
16 MHz
Accuracy
±10 ppm
Load Capacitance (C
L
)
10 pF
Shunt Capacitance (C
0
)
3 pF
Equivalent Series Resistance (ESR)
100
Drive Level (P
D
)
50
W
Table 14: Y2 32 kHz Crystal Characteristics
Reference Designator
Value
Part Number
ABS07-32.768KHZ-7-T
Frequency
32.768 kHz
Accuracy
±20 ppm
Load Capacitance (C
L
)
7 pF
Shunt Capacitance (C
0
)
0.9 pF to 1.2 pF
Equivalent Series Resistance (ESR)
70 k
Drive Level (P
D
)
0.5
W
9
QSPI Flash Memory
An 8 Mbit QSPI Data Flash memory (W25Q80EW) is provided to store user code. Its connection to
the DA14681 is fixed, as it interfaces dir
ectly with the chip’s Quad SPI Controller. The memory is
powered by the V18P rail. See section
7.1.3.2
for details on the power supply scheme.
Refer to the DA14681 datasheet (Ref.
[3])
for more details on connecting an external Flash memory.
An external QSPI Data Flash memory is not required when the DA14680 SOC is used. Please note
that the current implementation is done with DA14681.
10 TX Output Power Control Circuit
For DA14680/681 the FEM_VCC2 is tied to the V18 power rail via resistor R73. The TX output power
of the FEM is controlled by series resistor R73 = 16.5
, as well as the power level at the input. The
default output of V18 is 1.8 V, using this series resistor the voltage for FEM_VCC2 of the SKY66112-
11 is regulated to 1.2 V. For lower power output this series resistor can be further increased.
