There are various types of interface chips, which serve as "translators" and "traffic police" between electronic systems or modules within the system, responsible for functions such as data format conversion, protocol adaptation, level matching, timing control, and physical signal driving. The following is an original classification and sorting based on the main functions and application scenarios:
Core classification dimension: Connecting object and functional hierarchy
Interface chip between systems/devices (connecting different devices)
Wired communication interface chip:
USB controller/transceiver (PHY): Implement USB protocol stack (host/device/OTG), handle data packets, protocol negotiation, power management, etc. Including USB 2.0, USB 3. x, USB 4, USB Type-C, etc.
Ethernet Controller/PHY: Implementing the IEEE 802.3 standard, including MAC controller (handling data link layer) and PHY chip (handling physical layer encoding, modulation, and driving), supporting different rates (10/100/1000M/2.5G/5G/10G/25G+).
PCIe controller/Timer/Redriver: Implementing high-speed serial point-to-point interconnect standards, used for motherboards, graphics cards, storage expansion cards, etc. The controller handles the protocol layer, and Retimer/Redriver is used for signal relay enhancement.
HDMI/DVI/DisplayPort transmitter/receiver: a specialized transmission protocol for handling audio and video signals, content protection (such as HDCP), and high-speed serialization/deserialization.
SATA/SAS controller/PHY: used to connect storage devices (hard drives, SSDs).
Traditional serial interface: RS-232/RS-422/RS-485 transceiver, used for industrial control, long-distance, point-to-point or multi-point communication, characterized by simplicity and anti-interference.
Wireless communication interface chip:
Wi Fi/Bluetooth combination chip/module: integrates RF and baseband processing to achieve wireless LAN and short-range communication.
Cellular Communication Module (4G/5G): Integrated with complete cellular communication functions, used for the Internet of Things and mobile devices.
NFC/RFID controller/card reader chip: enables near-field communication and radio frequency identification.
Zigbee/Thread/Z-Wave and other low-power wide area network (LPWAN) chips: used for IoT sensor networks.
Industrial and vehicle bus interface chip:
CAN/CAN FD controller/transceiver: a reliable communication backbone in the automotive and industrial automation fields.
LIN transceiver: used for low-cost auxiliary networks in automobiles.
FlexRay transceiver: used for applications in automobiles that require high certainty and redundancy.
PROFIBUS/Modbus interface chip: a commonly used protocol in the field of industrial automation.
Industrial Ethernet PHY (such as EtherCAT, PROFINET, Powerlink): meets the special requirements of real-time and reliability in industrial environments.
Board level/chip to chip interface chip (connecting different chips or modules on the same system board)
Universal Serial Interface:
SPI Master/Slave Controller/Bridge: High speed, full duplex, master-slave synchronous serial bus, widely used to connect Flash, sensors, displays, etc.
I ² C/I ² S master/slave controller/buffer/level converter: I ² C is used for low-speed control (such as configuring registers), while I ² S is dedicated to transmitting digital audio data.
UART converter/bridge: converts UART signals to other interfaces (such as USB, SPI, I ² C), commonly used for debugging, connecting microcontrollers, and external devices.
Storage interface:
SD/eMMC controller/interface chip: Connect SD card and eMMC storage chip.
DDR memory interface chip (rare, usually integrated in SoC/CPU/FPGA): handles the complex timing and signal integrity of high-speed DDR SDRAM.
High speed SerDes interface chip:
SerDes (Sequencer/Desiializer): Convert parallel data into high-speed serial stream transmission and convert it back at the receiving end. It is the physical layer foundation for PCIe, SATA, USB 3. x+, HDMI, DisplayPort, high-speed Ethernet and other interfaces. Often integrated in SoC or ASIC in the form of IP cores, there are also independent chips used for signal enhancement or protocol conversion.
LVDS/MIPI sequencer/deserializer: specifically designed for display screen interfaces (such as LVDS for laptop screens and MIPI DSI for mobile phone screens) and high-speed sensor interfaces (MIPI CSI-2).
Parallel interface:
GPIO Expander: Expands the number of general-purpose input/output pins of a microcontroller through serial buses such as I ² C/SPI.
Parallel bus buffer/latch: enhances driving capability, isolates signals, and latches data (now less commonly used in high-speed fields and gradually replaced by serial).
Signal conditioning and conversion interface chip
Level converter/voltage converter: solves the voltage compatibility problem of communication between chips with different operating voltages (such as 1.8V, 3.3V, 5V).
Isolator:
Digital isolator (optocoupler/magnetic coupling/capacitive coupling): It transmits digital signals between electrically isolated circuits to protect system safety (against high voltage and grounding loops), commonly used in industry, medical, and power supply.
Isolated interface transceiver: such as isolated RS-485, CAN, I ² C, etc., combining communication protocols and electrical isolation.
Signal driver/repeater/buffer: Enhance the driving capability of signals, compensate for attenuation during long-distance transmission, and improve signal integrity.
Analog switch/multiplexer: Select one channel from multiple analog or digital signals for transmission.
Specialized functional interface chip
Charging management interface (such as USB PD controller): Negotiate and manage power transmission through interfaces such as USB Type-C.
Video capture/frame capture chip: captures images from analog video sources (such as CVBS) or digital video interfaces.
Audio codec: connects microphones and speakers to convert and process analog audio signals and digital audio data.
Sensor interface chip: specifically designed to connect specific types of sensors (such as bridge sensors, thermocouples), providing functions such as signal amplification, filtering, ADC, etc.
Summarize key points:
Protocol processing is the core: the core task of interface chips is to understand and execute specific communication protocols (USB, Ethernet, PCIe, I ² C, SPI, CAN, etc.).
Physical layer adaptation is crucial: responsible for converting logical signals into electrical/optical signals (drive, receive, encode, modulate) that can be reliably transmitted over physical media (wires, fibers, space).
Bridge function: It serves as a communication bridge between the digital world (between chips with different logic levels and timing requirements) and between the digital world and the external physical world/other devices.
Integration trend: Many complex interface functions (such as USB, Ethernet) are integrated into the main processor (SoC) or dedicated controller, but physical layer transceivers (PHY), level converters, isolators, signal conditioning chips, etc. usually still require independent chips to achieve high performance or special functions.
There are various performance indicators: speed (bandwidth), latency, power consumption, anti-interference ability, driving capability, isolation voltage, etc. are key selection criteria.
When selecting an interface chip, it is necessary to clarify: what is connected? What protocol is used (between devices or chips)? （USB？Ethernet？I²C？）、 What functions are needed? (Physical layer conversion only? Protocol processing? Isolation?) Performance requirements? (Speed, power consumption, reliability).