Under the trend of exponential growth in the volume of intelligent driving data, SerDes, as the core link connecting sensors, displays and computing platforms, needs to simultaneously meet the dual challenges of "high-speed transmission" and "high-reliability operation". In response to the differentiated demands of the GMSL/FPD-Link private protocol and the A-PHY public protocol, Lemao Electronics provides A full-link protection solution from power inrush to signal ESD. It ensures signal integrity through low junction capacitance (≤0.3pF) and high automotive-grade (EC-Q101) devices. Assist vehicle manufacturers in achieving "zero error code" data transmission in extreme environments ranging from -40 ℃ to +85℃ and complex electromagnetic interference.

一、SerDes' electromagnetic Challenges and Thunderbolt Solutions

In the vehicle-mounted environment, engine ignition pulses (ISO 7637-2 pulses 5a/5b), electrostatic discharge (ESD), and high-speed signal crosslinging are prone to cause distortion of SerDes signals. Differentiated protection schemes need to be designed for different protocol architectures.

Surge protection at the power supply end (12V system)

For the power supply end of the motherboard where the SerDes chip is located, the engine ignition pulse (ISO 7637-2 pulse 5a/5b) and the large current injection of BCI may cause signal distortion. The Thunderbolt adopts a separate high-power TVS or a combined scheme of PTC+TVS.

2. Signal end electrostatic protection (ESD)

A-PHY bus (Public Protocol)

A-PHY defines the following three different cable topologies, as shown in the following figure

Lemao's electrostatic protection for A-PHY adopts ULC0542CQ, which can be used in coaxial circuits as well as differential circuits. It complies with the EC-Q101 automotive standard certification, conforms to IEC 61000−4−2, grade 4, with air discharge ±25Kv, contact discharge 22Kv, and junction capacitance as low as 0.3pF, ensuring signal integrity.

GMSL/FPD-Link bus (Private Protocol)：

l Single-ended system (coaxial cable transmission) :

The single-ended system mode is composed of a single coaxial cable, which can transmit 12V power. It is mainly used for vehicle-mounted cameras. The thunderbolt adopts ULC1811CDNQ, with Cj=0.3pF(Typ.) low junction capacitance to ensure signal integrity. It meets IEC61000-4-2, level 4, and has a contact discharge of 15kV. Air discharge: 25kV.

l Differential system (transmission of two pairs of differential lines) :

The differential system mode is composed of two pairs of differential lines and is mainly applied to high-definition central control displays in vehicles, etc. Lei MAO recommends the integrated ULC3324P10LV, with Cj= 0.45pF(Typ.), packaged as DFN2510, providing single-chip protection for four differential lines. There is also ULC0342CDNHQ, with Cj= 0.22pF (Typ.), packaged as DFN1006, providing more flexible wiring.

三．The technical architecture of SerDes and its application value in vehicles

1. Technical principles and core advantages

SerDes (Serializer/Deserializer) converts multiple parallel data channels into high-speed serial signals for transmission and then restores them back to parallel data at the receiving end, achieving the full-process processing of "data compression - transmission - decompression". Its advantages include: high bandwidth, low latency, low power consumption, strong anti-interference ability, strong scalability, etc. It can support flexible networking of multiple data protocols such as HDMI, LVDS, MIPI, etc.

2. Typical applications in in-vehicle scenarios

SerDes is the data "nerve center" of intelligent cockpits and autonomous driving:

· Camera system: ADAS cameras (such as 8MP binocular vision modules) transmit raw image data to the domain controller via the GMSL/APIX protocol;

· Display system: The 4K central control screen and the full LCD instrument panel rely on FPD-Link/A-PHY to achieve uncompressed video transmission;

Cross-domain interconnection: High-resolution sensor data is exchanged between domain controllers through the A-PHY/R-LinC protocol to support L3 + level autonomous driving decision-making.

二、SerDes Mainstream protocol

1、The classification of mainstream SerDes protocols and the market competition pattern

The current market has formed a pattern where private protocols dominate and public protocols break through. The core protocol features and market shares are as follows：

协议名称	协议类型	速率范围	核心应用场景	市场占有率（2025 年）
GMSL	私有	3-12Gbps（GMSL3X）	ADAS 摄像头（8MP+）、360° 环视系统、激光雷达传输，覆盖 90% 以上高端车型	45%
FPD-Link	私有	3-10Gbps（FPD-Link IV）	车载显示屏（4K 中控屏 / 仪表盘）、车载信息娱乐系统，占据显示领域 70% 份额	40%
APIX	私有	1.5-12Gbps（APIX3）	多屏交互（后排娱乐屏）、域控制器互联，主要服务德国车企（宝马 / 大众）	3%
GVIF	私有	8.63Gbps（8MP@45fps）	索尼车载摄像头专用（如 IMX490），日系车型渗透率超 60% 但全球份额不足 1%	<1%
Clockless Link	私有	0.96-2.7Gbps	车载导航屏、低分辨率摄像头，主要配套罗姆传感器方案	<1%
AHDL	私有	10-20Gbps（第三代）	国产车型 360° 环视（如长安深蓝）、智能座舱显示，2024 年量产车型超 40 款	1%
R-LinC	私有	1.6-16Gbps	17MP 超高分辨率 ADAS 摄像头，获陕汽 / 广汽定点	<1%
A-PHY	公有	2-32Gbps（v2.0）	Fire protection two-bus electrostatic surge protection Automobile headlight technology evolution and protection scheme analysis Leave a Reply Your email address will not be published.Required fields are marked. * Name E-mail Content Verification code POPULAR BLOG 60V is the dividing line! In-depth analysis of key protection technologies for light electric vehicl POE Interface Surge Protection: From Board Burnout to a 4KV Worry-Free Design Solution — A Compliant Applications of Ultra-Low Capacitance (0.05pF) ESD Devices Save for later! Complete practical EMC protection solution for USB Type-C interfaces Medical‑Grade ESD and Surge EMC Protection Solution for Tinnitus and Hearing Loss Diagnosis and Trea ARCHIVES June 2026 May 2026 April 2026 March 2026 February 2026 January 2026 上海雷卯电子科技有限公司©版权所有