LPC5411x
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© NXP Semiconductors N.V. 2018. All rights reserved.
Product data sheet
Rev. 2.1 — 9 May 2018
89 of 105
NXP Semiconductors
LPC5411x
32-bit ARM Cortex-M4/M0+ microcontroller
13.4 I/O power consumption
I/O pins can contribute to the overall static and dynamic power consumption of the part.
If pins are configured as digital inputs with the pull-up resistor enabled, a static current can
flow depending on the voltage level at the pin. This current can be obtained using the
parameters I
pu
and I
pd
given in
If pins are configured as digital outputs, the static current is obtained from parameters IOH
and IOL shown in
, and any external load connected to the pin.
When an I/O pin switches in an application, it contributes to the dynamic power
consumption because the V
DD
supply provides the current to charge and discharge all
internal and external capacitive loads connected to the pin.
The contribution from the I/O switching current I
sw
can be calculated as follows for any
given switching frequency f
sw
if the external capacitive load (C
ext
) is known (see
for the internal I/O capacitance):
I
sw
= V
DD
x f
sw
x (C
io
+ C
ext
)