IN Brief:
- TDK has added a 1.25 µH component to its MLJ1608-G automotive power over coax inductor series.
- Impedance is 1.7 to two times higher than the previous 0.56 µH product between 100 MHz and 700 MHz.
- The AEC-Q200 compliant component is rated at 350 mA at 105°C and 200 mA at 125°C.
TDK has expanded its MLJ1608-G multilayer inductor series with a 1.25 µH component for automotive power over coax circuits, increasing impedance while keeping a 1.6 × 0.8 × 0.8 mm package.
The MLJ1608WGC1R2MTD25 entered mass production in October and is AEC-Q200 compliant. TDK reports impedance 1.7 to two times higher than its previous component across the 100 MHz to 700 MHz range, while the series maintains useful impedance characteristics at frequencies reaching 2 GHz.
TDK compares the new design at approximately 1.2 µH with an earlier 0.56 µH product, while the production part itself is specified at 1.25 µH ±20% when measured at 25 MHz. Typical DC resistance is 0.81 Ω, with a maximum of 1.20 Ω.
Power over coax combines DC supply and high speed data on a single coaxial cable between an automotive camera and its electronic control unit. Using one cable instead of separate power and signal connections can reduce harness count, connector requirements and packaging volume where several cameras are distributed around a vehicle.
The shared conductor requires a bias network at each end of the link. DC power has to pass towards the camera while the high frequency data signal is kept out of the vehicle power network, so inductors are placed in the power branch to present high impedance to the communications signal without blocking the DC supply.
A real inductor does not behave like an ideal inductance across the entire frequency range because winding or electrode structure, resistance and parasitic capacitance all influence its response. Raising nominal inductance can increase impedance through part of the required band, but self resonance and parasitic effects eventually limit how far that benefit extends.
PoC filters therefore use several components with different values rather than one large inductor. Each part contributes impedance over a particular section of the communications band, allowing the overall network to isolate the power path without introducing an unwanted resonance or excessive loss into the data channel.
TDK attributes the MLJ1608-G response to its multilayer material and internal structure. The new component raises nominal inductance without moving beyond the 1608 package, giving designers more impedance through the lower and middle portion of the PoC spectrum without consuming additional PCB area inside a compact camera module.
Current handling remains part of the compromise because the same component carries the camera’s DC supply. TDK rates the new part at a maximum of 350 mA at 105°C and 200 mA at 125°C. The lower current rating at the higher temperature limits self heating and keeps the component within its specified thermal range.
The MLJ1608-G series operates from -55°C to 125°C, covering the temperature range expected around vehicle mounted camera electronics. Exterior, windscreen and body mounted modules can face solar loading, winter ambient conditions and heat from nearby electronics while still carrying both power and data through the same link.
Camera bandwidth is also increasing as resolution and frame rates rise. Faster serializer and deserializer links extend the frequency range that the PoC network has to accommodate, leaving less tolerance for insufficient impedance, unwanted resonances or leakage of radio frequency energy into the power branch.
The inductor does not improve image processing or camera resolution directly; it preserves separation between the power feed and communications path. If the bias network presents too little impedance at data frequencies, signal energy can escape into the supply network, reducing signal integrity and spreading unwanted RF energy through the surrounding wiring.
TDK offers multilayer, thin film and wire wound inductors for PoC because each construction balances inductance, current capacity, package size and high frequency response differently. The 1.25 µH MLJ1608-G adds a higher impedance option within the existing compact footprint, extending the choices available when camera designers build a broadband bias network around limited board space.
