The PCMF1USB3SZ, PCMF1USB3B/CZ, and PCMF2USB3SZ are Nexperia common-mode EMI filters with integrated ESD protection. They suppress common-mode interference and protect downstream circuitry in high-speed differential interfaces such as USB and HDMI. Their main differences are differential channel count, ESD protection configuration, and differential-mode bandwidth.
Parameter Comparison
| Parameter | PCMF1USB3SZ | PCMF1USB3B/CZ | PCMF2USB3SZ |
| Differential channels / signal lines | 1 / 2 | 1 / 2 | 2 / 4 |
| ESD protection configuration | Unidirectional | Bidirectional | Unidirectional |
| Differential −3 dB cutoff frequency | 6 GHz typ. | 8.1 GHz typ. | 6 GHz typ. |
| Input ESD contact discharge | ±15 kV | ±20 kV | ±15 kV |
| Series resistance per line | 3 Ω typ. | 2.6 Ω typ. | 3 Ω typ. |
| Diode capacitance | 0.25 pF typ. | 0.3 pF typ. | 0.25 pF typ. |
| Input voltage absolute limits | −0.5 to +5 V | −4 to +4 V | −0.5 to +5 V |
| Ambient operating temperature | −40 to +125°C | −40 to +125°C | −40 to +125°C |
| Package and nominal body dimensions | WLCSP5 0.77 × 1.17 mm | WLCSP5 0.77 × 1.17 mm | WLCSP10 1.57 × 1.17 mm |
Application Fit
- PCMF1USB3SZ
The PCMF1USB3SZ handles one differential pair per device. It suits single-channel designs and allows separate placement for pairs located farther apart. In a USB Type-C connector layout, for example, power or ground pins separate some data pairs. Individual single-channel devices allow placement close to each pair while keeping traces direct.
- PCMF1USB3B/CZ
The PCMF1USB3B/CZ suits a single differential pair requiring a bidirectional ESD protection structure. Compared with the PCMF1USB3SZ, it offers a wider differential passband, lower series resistance per line, and a higher input ESD contact discharge rating. It is the option to consider when these electrical characteristics are priorities. “Bidirectional” describes the protection structure, independently of data flow direction.
- PCMF2USB3SZ
The PCMF2USB3SZ integrates two differential channels in one WLCSP10 package. Where two pairs are routed close together, one device provides filtering and ESD protection for both, reducing the number of filter/protection devices from two single-channel parts to one.
Design Considerations
- Identify the Connector Side and the Circuit Side
Connect CH_IN to the external connector side and CH_OUT to the internal circuitry, following the datasheet pin assignments. All three devices have an output-to-ground ESD contact discharge rating of ±2 kV, which differs from the input ratings listed in the comparison table.
- Check Noise Attenuation and Signal Loss Separately
Use the common-mode transmission curve, S21cc, to check attenuation at the interference frequencies identified during EMI testing. Use the differential-mode transmission curve, S21dd, and eye-diagram testing to assess signal quality with the filter installed. These checks address noise suppression and the filter’s effect on the wanted signal, respectively.
- Connect Both Grounds on the Two-Channel Device
On the PCMF2USB3SZ, B1 and B2 are the ground pins for the two channels and are not internally connected. Connect both to PCB ground. Placement should also preserve differential impedance and pair symmetry without introducing unnecessary routing detours.
Product Summary
| Part | Manufacturer | Selection focus | Buy |
| PCMF1USB3SZ | Nexperia | One channel for distributed placement | Buy Now |
| PCMF1USB3B/CZ | Nexperia | Bidirectional ESD and wider differential bandwidth | Buy Now |
| PCMF2USB3SZ | Nexperia | Two channels for closely routed pairs | Buy Now |
Select according to signal voltage, channel count, noise frequencies, and system validation. Visit WIN SOURCE to check current inventory and pricing.
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