There are various packaging forms for ESD static protection tubes, which can be mainly divided into the following three categories based on size, number of channels, and application requirements:
1、 Ultra small package (suitable for high-density PCB design)
DFN0603-2L (0201)
Size: 0.6mm × 0.3mm × 0.3mm
Features: Currently one of the smallest packages, used for portable devices with extremely limited space (such as TWS earphones, smartwatches).
DFN1006-2L (0402)
Size: 1.0mm × 0.6mm × 0.5mm
Features: Balanced size and protection capability, commonly found in USB 2.0, audio interfaces, etc.
SOD-882 (0603)
Size: 1.2mm × 0.8mm × 0.6mm
Features: Low capacitance (can be as low as 0.05pF), suitable for high-speed signals such as USB 3.0.
2、 Universal packaging (mainstream applications)
SOD-323
Size: Approximately 1.7mm x 1.2mm
Features: Low cost, easy to solder, widely used for low-frequency signal protection such as GPIO and button circuits.
SOD-523 (0603)
Size: 1.2mm × 0.8mm × 0.6mm
Features: Compatible with standard SMT processes, suitable for consumer electronics power ports.
SOT-23
Size: 3.0mm × 1.3mm × 1.0mm
Features: Supports single/bidirectional protection, mostly used for analog signals or low-voltage digital interfaces (such as I ² C).
3、 Multi channel integrated packaging (complex interface protection)
SOT-23-6L
Features: Integrated 4-6 protection channels, suitable for multi line interfaces (such as SIM card slots, SD card slots).
SOIC-8/SOIC-16
Features: Supports 8-16 high-density protection channels, used for multi pin interfaces such as Ethernet ports and HDMI.
DFN2510-10L
Size: 2.5mm × 1.0mm × 0.6mm
Features: 10 channel integration, balancing compactness and high protection level (such as industrial control equipment).
Key considerations for selection
Signal type: High speed interface (USB 3.1, HDMI 2.0) requires a capacitance of<0.5pF (such as DFN1006); Low frequency signals can be relaxed to 30pF (such as SOD-323).
Space limitation: DFN0603 or SOD-882 are preferred for ultra small devices; SOT-23 is optional for general scenarios.
Protection level: The larger the package size, the larger the chip area, and the stronger the ability to withstand current (such as SOIC-16 having stronger protection than SOD-323).
Tip: The actual selection needs to be comprehensively evaluated based on parameters such as working voltage (VRMM), clamp voltage (VC), junction capacitance (CJ), etc. For example, the USB 3.1 interface requires the selection of DFN packaged devices with VC ≤ 8V and CJ<0.3pF to ensure signal integrity.
