UM11158
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© NXP B.V. 2019. All rights reserved.
User manual
Rev. 1.2 — 25 April 2019
14 of 24
NXP Semiconductors
UM11158
LPCXpresso55S69 Development Board
5. Board Power
The LPCXpresso55S69 board re5V input to power the on-board voltage low
dropout linear regulators, of which there are 3, all available from Torex Semiconductor.
The Link2 Debug probe has a 2.5V regulator (U10) which draws power from USB
connector P6 (“Debug Link”) only. The Debug Probe is unpowered if P6 is unconnected.
There are two other regulators, providing the option of 1.8V (U8) or 3.3V (U9) to the other
devices on the board; these regulators can be powered by any of the following (+5V)
sources:
•
USB +5V Power only connector (P5)
•
USB Full Speed connector for LPC55S69 (P10)
•
USB High Speed connector for LPC55S69 (P9)
•
USB Debug Link connector (P6)
The +5V sources above are connected via protection diodes to prevent reverse powering
of any of them by another source. The +5V output of these combined sources is also
connected to the Arduino and Mikroe expansion sites. Note that if P9 or P10 is configured
as a USB host port then those connectors will not supply power to the board and another
source must be provided.
The LPC55S69 device requires a minimum supply voltage of 1.85V, so jumper P4 must
be set in the 3.3V position, or an external supply provided to the center pin of P4. Note
that the MMA8652 Accelerometer and use of most SD cards requires the board to be
configured for 3.3V operation. The power connection to the Accelerometer may be
disconnected by removing R20; installing header P25 provides a convenient way to
connect/disconnect this.
For further details, refer to the board schematics.
5.1 Measuring LPC55S69 supply current
Current supply to the LPC55S69 Core can be measured via P29 (supply into VDDA and
the on-board DC-DC converter) by removing R85. Supply current into the entire device
(VDDA, DC-DC and I/O) can be measured via P13 (removing R92), or by measuring the
voltage drop across the 2.43 ohm resistor (R91) which is accessible at P12.
6. Board serial connections
This section describes connections between LPC55S69 on-board serial peripherals and
connectors for use with off-board devices.
6.1 LPC55S69 USB Ports
The Board incorporates micro AB connectors for both of USB0 (Full Speed, connector
P10) and USB1 (High Speed, connector P9) ports of the LPCXpresso55S69. Both of
these ports are capable of operating as a device or a host, and this is why micro AB
connectors are used.