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TDK: How to select the right PoC Filter Inductors and Chip Beads for Automotive SerDes (LVDS) Transmission
This article presents examples of the use and effects of PoC filter inductors and chip beads.
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Figure 1: PoC transfer system
What is PoC (Power over Coax)?
PoC (Power over Coax) is a transmission system that reduces the number of wires by simultaneously transmitting signals and DC power on a single coaxial cable.
In order to separate the DC power supply from the broadband signals, the system is characterized by the use of a DC-cutting capacitor on the signal line side and a filter inductor on the power supply line to prevent the inflow of broadband signals.
There are a number of communication standards led by IC manufacturers and standardization organizations as shown below, and the appropriate inductor must be selected to match the respective signal transmission speed and power supply.
Table 1: Major SerDes standards supporting PoC
PoC (Power Over Coax) for higher speed and power
Sensing devices such as cameras and radar equipment are becoming increasingly high-capacity, high-functionality, and multifunctional as sensing accuracy improves, requiring higher transmission speeds and more power. As a result, PoC filters are required to support higher transmission speeds, from approximately 1.5 Gbps to 10 Gbps or more, and higher supply power, from 1 W to 5 W.
Figure 2: Camera module for Autonomous-Driving / ADAS
What is an inductor (coil) optimized for PoC filters?
Space is often restricted in automotive camera modules and other products, requiring miniaturization of the product and reduction of the mounting area. A typical filter consists of four inductors together with chip beads, but constraints can often limit the number of products on the mount. In order to reduce the number of inductors, a product that can maintain impedance frequency characteristics over a wide bandwidth is required. At the same time, this device must maintain its characteristics in high-temperature environments and operate at temperatures up to 150°C.
Figure 3: Example of a typical PoC filter configuration
37% reduction in mounting area
Under the same conditions as the general PoC filter configuration example above, TDK's inductors for PoC filters can be realized with one inductor and two chip beads. This reduces the mounting area by 37%.
Table 2: TDK inductors recommended for PoC filter use
Impedance characteristics maintained over a wide bandwidth
Figure 4: Effect of TDK inductors for PoC filter use
TDK inductors for PoC filters
As shown in the diagram (Figure 5) below, TDK offers a wide range of inductors for PoC filters that meet your usage conditions, such as allowable current and filter requirements.(See table below: "TDK inductors for PoC (Power over Coax) filter circuits") The MLJ1608-G series, which is compact and covers a high frequency bandwidth, contributes to a space saving filter design. The ADL series is a product that supports a wide bandwidth, and reduces the overall number of filter coils. The ADL4524VL and ADL8030VA series, which cover an even wider bandwidth, are currently under development. The ADL4532VK and ADL3225VF series are also under development for high current applications.
Figure 5: Types of inductors for PoC filter use
TDK inductors for PoC (Power over Coax) filter circuits
With the increasing speed and sophistication of in-vehicle interfaces, PoC is being promoted in camera systems with SerDes transmission, etc. To separate broadband signals and power in PoC, a wide-band, high-impedance filter using an inductor is required. TDK has a diverse product line-up and can propose filter configurations to suit the current capacity and communication speed of the circuits used.
*Product names in red can be used in 125°C environments.
*The above figures are based on an operating ambient temperature of 105°C. For 125°C environments, the combination may vary, so please contact us for more information.
Table 3: Solution Map
The above PoC filter combinations are examples of TDK products that are used as references by IC manufacturers or filter combinations recommended by TDK. For choosing the best PoC filter combination under other conditions, use the TDK PoC Selection Tool.
www.tdk.com
What is PoC (Power over Coax)?
PoC (Power over Coax) is a transmission system that reduces the number of wires by simultaneously transmitting signals and DC power on a single coaxial cable.
In order to separate the DC power supply from the broadband signals, the system is characterized by the use of a DC-cutting capacitor on the signal line side and a filter inductor on the power supply line to prevent the inflow of broadband signals.
There are a number of communication standards led by IC manufacturers and standardization organizations as shown below, and the appropriate inductor must be selected to match the respective signal transmission speed and power supply.
Table 1: Major SerDes standards supporting PoC
PoC (Power Over Coax) for higher speed and power
Sensing devices such as cameras and radar equipment are becoming increasingly high-capacity, high-functionality, and multifunctional as sensing accuracy improves, requiring higher transmission speeds and more power. As a result, PoC filters are required to support higher transmission speeds, from approximately 1.5 Gbps to 10 Gbps or more, and higher supply power, from 1 W to 5 W.
Figure 2: Camera module for Autonomous-Driving / ADAS
What is an inductor (coil) optimized for PoC filters?
Space is often restricted in automotive camera modules and other products, requiring miniaturization of the product and reduction of the mounting area. A typical filter consists of four inductors together with chip beads, but constraints can often limit the number of products on the mount. In order to reduce the number of inductors, a product that can maintain impedance frequency characteristics over a wide bandwidth is required. At the same time, this device must maintain its characteristics in high-temperature environments and operate at temperatures up to 150°C.
Figure 3: Example of a typical PoC filter configuration
37% reduction in mounting area
Under the same conditions as the general PoC filter configuration example above, TDK's inductors for PoC filters can be realized with one inductor and two chip beads. This reduces the mounting area by 37%.
Table 2: TDK inductors recommended for PoC filter use
Impedance characteristics maintained over a wide bandwidth
Figure 4: Effect of TDK inductors for PoC filter use
TDK inductors for PoC filters
As shown in the diagram (Figure 5) below, TDK offers a wide range of inductors for PoC filters that meet your usage conditions, such as allowable current and filter requirements.(See table below: "TDK inductors for PoC (Power over Coax) filter circuits") The MLJ1608-G series, which is compact and covers a high frequency bandwidth, contributes to a space saving filter design. The ADL series is a product that supports a wide bandwidth, and reduces the overall number of filter coils. The ADL4524VL and ADL8030VA series, which cover an even wider bandwidth, are currently under development. The ADL4532VK and ADL3225VF series are also under development for high current applications.
Figure 5: Types of inductors for PoC filter use
TDK inductors for PoC (Power over Coax) filter circuits
With the increasing speed and sophistication of in-vehicle interfaces, PoC is being promoted in camera systems with SerDes transmission, etc. To separate broadband signals and power in PoC, a wide-band, high-impedance filter using an inductor is required. TDK has a diverse product line-up and can propose filter configurations to suit the current capacity and communication speed of the circuits used.
*Product names in red can be used in 125°C environments.
*The above figures are based on an operating ambient temperature of 105°C. For 125°C environments, the combination may vary, so please contact us for more information.
Table 3: Solution Map
The above PoC filter combinations are examples of TDK products that are used as references by IC manufacturers or filter combinations recommended by TDK. For choosing the best PoC filter combination under other conditions, use the TDK PoC Selection Tool.
www.tdk.com
