Chip Inductor for Automotive (Chip Coil for Automotive) Power Inductor (Wire Wound Type for Choke) # Technical Document: LQH32CH4R7M23L Inductor
Manufacturer : MURATA
Component Type : Multilayer Chip Inductor (Ferrite-based, Shielded Construction)
Series : LQH32C
Last Updated : October 2023
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## 1. Application Scenarios
### 1.1 Typical Use Cases
The LQH32CH4R7M23L is a 4.7 µH (±20%) multilayer shielded power inductor designed for noise suppression and energy storage in compact DC-DC converter circuits. Its primary function is to serve as the main energy storage element in switch-mode power supply (SMPS) output stages, particularly in buck , boost , and buck-boost converter topologies . The component's shielded construction minimizes electromagnetic interference (EMI) radiation, making it suitable for noise-sensitive applications.
### 1.2 Industry Applications
* Consumer Electronics : Used in voltage regulator modules (VRMs) for smartphones, tablets, wearables, and digital cameras. Commonly found in point-of-load (POL) converters powering processors, memory, and display subsystems.
* Telecommunications : Implements DC-DC conversion in networking equipment such as routers, switches, and baseband units, where stable power delivery and low EMI are critical.
* Automotive Electronics : Employed in infotainment systems, advanced driver-assistance systems (ADAS), and body control modules. The component's construction supports operation in environments with moderate temperature fluctuations and vibration.
* Industrial Control Systems : Powers sensors, microcontrollers, and communication interfaces in PLCs, motor drives, and instrumentation where reliable power conversion in confined spaces is required.
### 1.3 Practical Advantages and Limitations
Advantages:
* Space Efficiency : The compact 1210 footprint (3.2mm x 2.5mm) and low profile (2.0mm max. height) enable high-density PCB designs.
* EMI Shielding : The magnetic shield significantly reduces stray magnetic flux, minimizing crosstalk with adjacent circuits and simplifying EMI compliance testing.
* High Reliability : Multilayer construction and robust termination provide good resistance to mechanical stress and thermal cycling.
* Suitable Saturation Current : The `Isat` rating (see Specifications) is optimized for typical mid-power DC-DC converter applications, providing a good balance between size and performance.
Limitations:
* Limited Current Handling : Compared to larger wire-wound or molded inductors, its saturation and RMS current ratings are lower, restricting use to low-to-mid power applications (typically under 3A DC).
* Frequency-Dependent Losses : Core losses increase significantly at high switching frequencies (above ~3 MHz), which can reduce overall converter efficiency.
* Tolerance : The ±20% inductance tolerance is standard but may require feedback loop compensation designed for worst-case values in precision applications.
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## 2. Design Considerations
### 2.1 Common Design Pitfalls and Solutions
* Pitfall 1: Operating Near Saturation Current (`Isat`)
Problem : Exceeding `Isat` causes a sharp drop in inductance, leading to increased peak current, regulator instability, and potential MOSFET failure.
Solution : Select the inductor such that the peak inductor current in the application remains below 70-80% of the rated `Isat` under all operating conditions, including transients.
* Pitfall 2: Ignoring Core Losses at High Frequency
Problem : At switching frequencies above 1-2 MHz, core losses (proportional to ΔB²f) can become dominant, causing excessive component heating and efficiency degradation.
Solution : Calculate total inductor losses (DC copper loss
