How do I start selecting an LPC MCU?

List the interfaces and the I/O you need, estimate the flash and the SRAM from the code and the data, then choose the core and the package that cover the design with headroom. Those decisions narrow the selection quickly.

Which LPC core should I choose?

Choose the Cortex-M0 or M0+ for a low-cost, low-power task, the Cortex-M3 for a mainstream control and connectivity application and the Cortex-M4 for a signal-processing or a motor-control workload. All use the MCUXpresso toolchain. Our FAE team can help match the core.

How much memory do I need?

Estimate the flash from the code and the constant tables and the SRAM from the stack, the heap and the buffers, then add headroom. The LPC1768 gives 512 KB of flash, the LPC54606 gives 136 KB of SRAM for a large buffer and the LPC11U68 gives 256 KB of flash on a Cortex-M0+. Our FAE team can help size the memory.

Are the devices genuine and documented?

Every NXP device BeiLuo ships is factory-traceable and includes an import declaration, a certificate of origin and a RoHS compliance file. Mainstream models are held in regional warehouses. Click a model for stock status, or request a quote for current lead time.

How do I start selecting an interface IC?

Decide whether you need more I/O ports or a bus switch, then choose the channel count and the package and confirm the voltage and the interrupt against the host. Those decisions narrow the selection quickly.

I/O expander or bus switch?

Choose an I/O expander such as the PCA9555 or PCA9554 to add buttons, LEDs and control lines to a small host, and a bus switch such as the PCA9548A to fan out the bus, resolve an address conflict or isolate a section. Our FAE team can help choose.

How many devices fit on one bus?

The address pins allow several expanders and switches on one I2C bus, so a designer adds I/O and buses without a larger host. Keep the total capacitance in mind and divide the bus with a switch where it grows large. Our FAE team can review the addressing.

How do I start selecting an NFC device?

Decide whether you need a reader or a secure element, choose the reader from the cards and the protocols you must handle, then confirm the host interface and the package. Those decisions narrow the selection quickly.

Choose the PN532 for a full NFC controller with reader, card and peer-to-peer modes and a broad protocol support, and the MFRC522 for a low-cost reader for ISO/IEC 14443A and MIFARE. Both connect over SPI, I2C or UART. Our FAE team can help choose the reader.

When do I need a secure element?

Use the SE050 where the product must store a key or an identity in tamper-resistant hardware and prove it, such as a secure transaction or a device authentication. It provides a root of trust beside the reader over I2C. Our FAE team can help with the security design.

How do I choose the pull-up resistors?

The pull-ups set the rise time and the speed, so choose them from the bus voltage, the total capacitance and the speed. A value that is too large gives a slow edge and a value that is too small wastes power and loads the driver. Read the notes for the calculation.

When do I need an I2C switch?

Use an NXP PCA9548A switch when several devices share an address, when the bus capacitance is too large, or when a section must be isolated or hot-plugged. The switch fans the upstream pair out to eight sections and can translate the voltage. Our FAE team can help plan the bus.

How do I lay out the I2C bus?

Keep the bus traces short, place the pull-ups and the decoupling close to the devices and keep the bus away from the noisy switching nodes. Use a ground plane and keep the capacitance within the limit. Our FAE team can review the layout.

What is the standout feature of the NXP range?

The standout feature is the combination of a broad LPC microcontroller family across several Arm Cortex-M cores with a reference I2C interface family and a leading NFC and secure line, so one supplier covers the control, the bus and the contactless interface. The main design care points are the bus and the antenna.

How do the LPC MCUs perform?

In practice the LPC family gives a good performance for the cost, with the familiar Arm core and a rich peripheral set. On the bench the cores ran at their rated clock and the interfaces behaved as the datasheet describes. Confirm the peripheral differences for your design.

How do the interface and NFC parts perform?

The I2C switch and expanders give a reliable bus expansion when the pull-ups and the capacitance are right, and the NFC readers read the reference cards at the expected range when the antenna is tuned. The secure element provides a root of trust over I2C. Our FAE team can review the bus and the antenna.

Can I get samples to evaluate?

Yes. We provide samples of the NXP MCUs, interface ICs and NFC devices for your own performance, bus and read-range testing, with documentation included and FAE support during bring-up. Request a sample and we will confirm stock and lead time.

Technical Support | NXP Expertise | BeiLuo

Guides, application notes and reviews from BeiLuo's FAE team covering NXP LPC microcontrollers, I2C and GPIO interface ICs and NFC devices in full detail.

Guides 3 Application Notes 1 Troubleshooting 0 Reviews 1

How to Select an NXP LPC MCU

2026-07-26 - Guides - By Zhang Wei Ming

Compare NXP LPC microcontrollers by core, flash, SRAM, speed, interfaces and package for embedded control and connectivity designs and real systems today.

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How to Select an NXP Interface IC

2026-07-21 - Guides - By Li Jian Guo

Compare NXP interface ICs for the I2C bus by function, channel count, voltage, interrupt and package for GPIO expansion and system control and boards.

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How to Select an NXP NFC Device

2026-07-16 - Guides - By Wang Hui Long

Choose an NXP NFC reader or secure device by protocol, interface, data rate and package for contactless payment, access and identification and products.

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NXP I2C Bus Design Notes and Layout

2026-07-09 - Application Notes - By Li Jian Guo

I2C bus design notes for NXP parts: pull-ups, capacitance, the switch and expander, addressing and layout for a reliable bus in a real product system.

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NXP MCU and Interface Review Report

2026-06-30 - Reviews - By Zhang Wei Ming

A hands-on review of NXP LPC microcontrollers and I2C interface and NFC devices for embedded designs, covering support and reliability in real systems.

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Meet Our FAE Team

Zhang Wei Ming

Senior FAE Engineer, MCUs

LPC MCUsCortex-MEmbedded

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Li Jian Guo

FAE Engineer, Interface and Buses

I2C BusI/O ExpandersLayout

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Wang Hui Long

FAE Engineer, NFC and Security

NFCAntennaSecure Element

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