components used in ADAS1 and AD2 systems need to be extremely reliable. With this in mind, TDK developed the CLT32 series of inductors for power management units and set new benchmarks in reliability, miniaturization and electrical parameters.
In ADAS and AD systems, high-performance processors are required with ultra-high processing speed and processing power to evaluate data from different sensors, control actuators, and Display information on displays. These processors are supplied with no more than 1 V, but require double-digit currents. PMICs (Power Management ICs) are used as power supplies to provide the required high currents by combining with multi-phase outputs. The key element in stabilizing these currents is the power Inductor at the output. Figure 1 shows a typical topology of an 8-phase PMIC unit used to power a processor.
Figure 1: Operation of an 8-phase PMIC unit with 8 CLT32 power inductors used to power the processor.
1 Advanced driver assistance systems
2 Autonomous driving
New TDK Inductors Meet the Toughest Requirements
Inductors used in PMICs in the automotive industry must meet very high electrical and mechanical requirements, including:
compact form factor
Large saturation current
Ultra low RDC
Low power consumption
suitable for high frequencies
Can be used in high ambient temperature
To meet all the above requirements, TDK’s new CLT32 series of power inductors uses innovative design principles. This involves solid copper coils moulded from a special ferromagnetic plastic composite. Since the coil core and housing are formed at the same time, this provides a huge advantage.
Figure 2: Sectional view of the new design: The ferromagnetic plastic composite forms both the coil core and the housing.
Another advantage of this innovative design is the absence of internal wiring, as the ends of the coils have been designed as terminals, as shown in Figure 2. This design principle brings two significant advantages for automotive applications: greatly improved reliability and ultra-low RDC values.
Pioneer in miniaturization and high electrical performance
Through an innovative design concept, the CLT32 series inductors are only 3.2 x 2.5 mm2 in size and 2.5 mm in height, requiring less than a quarter of the installation space of competing products. A key factor is that multiple power inductors of this series can be used simultaneously in a PMIC topology, which can significantly reduce PCB board size.
In addition to size, the new series has significantly better electrical performance than the competition. For example, the high frequency AC current losses of the CLT32 series are significantly lower compared to thin film or metal composite technologies, as shown in Figure 3.
Figure 3: The power loss of the metal composite inductor at 2 A ripple current is 0.28 W, while the value of the new TDK inductor is only 0.18 W.
The CLT32 family of inductors also outperforms other technologies in terms of efficiency and saturation current drift over temperature, with inductance values ranging from 17 nH to 440 nH, rated operating currents from 10 A to 45 A, and saturation currents up to 60 A. up to 165°C, which is ideal for automotive applications. In addition, with a wide frequency range up to 10 MHz, this rugged inductor is also ideal for GaN semiconductor applications.
Figure 4: Measuring just 3.2 x 2.5 mm2 and 2.5 mm high, the CLT32 series of power inductors have excellent electrical characteristics and are a new benchmark in miniaturization.