NXP Semiconductors FRDM-MCXN947 - Clocks

NXP Semiconductors
UM12018
FRDM-MCXN947 Board User Manual
Solder options for resistorsMode
R14 R18 R19 R17 R194 R20
• DCDC_CORE disable
• LDO_CORE enable
DNP DNP DNP Populate Populate Populate
Table 9. Power supply configurations for DCDC and LDO operation...continued
2.1.2 DC-DC inductor
The FRDM-MCXN947 board uses a 1.5 μH DC-DC inductor L2 (SHENZHEN SUNLORD SPH252012H1R5MT).
The inductor is enabled when the board is configured in DC-DC Buck mode. Figure 8 shows the DC-DC
inductor circuit diagram of the FRDM-MCXN947 board.
Choosing the right DC-DC inductor for your target board is important. When selecting a DC-DC inductor, refer to
the specifications mentioned in the MCX N94x, N54x Product Family Data Sheet.
2.2 Clocks
The FRDM-MCXN947 board provides crystal oscillators to provide accurate time bases for the device and
different components on the board.
Table 10 describes the clock sources available on the FRDM-MCXN947 board.
Clock
generator
Clock
frequency
Destination Description
Crystal
oscillator, Y1
(830108212309,
Wurth
Electronics)
24 MHz • Port 1 pin 30 (XTAL48M) of target
MCU MCXN947
• Port 1 pin 31 (EXTAL48M) of target
MCU MCXN947
For high-frequency accurate timebase
• Required external load capacitors are
provided
• Small package size (2.0 mm x 1.6 mm)
• Low-ESR (100 Ω max) crystal
Crystal
oscillator, Y2
(830009678,
Wurth
Electronics)
32.768 kHz • Port 5 pin 1 (XTAL32K) of target
MCU MCXN947
• Port 5 pin 0 (EXTAL32K) of target
MCU MCXN947
For accurate low-power timebase
• Internal load capacitors provide the entire
crystal load capacitance
• To measure the 32.768 kHz oscillator
frequency, enable the RTC_CLKOUT signal
to be available on the P5_3 pin. It can be
observed at pin5 of connector J2
Crystal
oscillator, Y3
(ECS-2333-
500-BN-TR)
50 MHz RMII 10/100 Mbit/s Ethernet transceiver
LAN8741A-EN (U9)
Provides clock at XTAL1/CLKIN pin of
Ethernet PHY depending upon the R154
resistor setting (DNP by default). Also, it
provides a provision to feed the clock back
into the target MCU (MCXN947) through Port
P1 pin 4 (P1_4/ENET_TXCLK)
Crystal
oscillator, Y4
(830064296,
Wurth
Electronics)
16 MHz XTAL32M_N/P pins of LPC55S69
MCU-Link
Option for external clock input
Table 10. FRDM-MCXN947 clocks
UM12018 All information provided in this document is subject to legal disclaimers. © 2024 NXP B.V. All rights reserved.
User manual Rev. 1 — 20 January 2024
13 / 41