TDK has extended its X2 safety film capacitor portfolio with the B3292xU/V series, adding compact 350 V AC types for interference suppression in demanding industrial and automotive environments in series with the mains.
The series targets engineers who need higher AC voltage capability, AEC‑Q200 compliance, and small footprints for on‑board chargers, EV charging systems, PV inverters, and other grid‑connected electronics.
Key features and benefits
The new B3292xU/V film capacitors are X2‑class safety capacitors designed for EMI suppression “across the line” and for use in series with the mains in single‑phase systems. They are suitable wherever space is tight but elevated AC voltages and robust surge capability are required.
Main electrical and construction features include:
- X2 safety class for interference suppression in across‑the‑line and series‑with‑mains positions
- Rated voltage of 350 V AC for the new compact variants, supporting higher mains and derating margins
- Peak pulse voltage capability up to 2.5 kV in accordance with IEC 60384‑14
- High DC test voltage of 1505 V for 2 s, underlining insulation strength
- Capacitance range for the new compact versions from 47 nF to 1.8 µF with 15 mm and 22.5 mm lead spacing
- Overall B3292xU/V family coverage from 47 nF up to 20 µF with lead spacings from 15 mm to 52.5 mm
For engineers, the combination of higher AC rating and compact dimensions enables more generous design margins in universal input systems, or the option to reduce the number of parallel capacitors for the same effective capacitance and safety performance. Good self‑healing properties support long‑term stability after transient overvoltage events.
The series is specified for severe ambient conditions:
- Maximum operating temperature up to +110 °C
- THB (temperature, humidity, bias) test passed at +85 °C, 85% RH, rated voltage, 1000 h to Grade III, Test Condition B
- AEC‑Q200 compliant versions for automotive use
This robustness is important for equipment mounted in harsh environments such as charging stations, outdoor PV inverters, or under‑hood automotive electronics.
Typical applications
TDK positions the B3292xU/V capacitors as EMI suppression components in AC‑connected power electronics, especially where compact size and automotive qualification are required.
Typical use cases include:
- Capacitive power supplies and compact auxiliary power stages connected directly to the mains
- Energy meters and smart metering equipment with limited PCB area and long service life requirements
- Industrial drives and motor control units where filters must fit into narrow drive housings
- On‑board chargers (OBC) in electric vehicles, particularly in EMI filters in series with the mains input
- EV charging stations and wallboxes (AC side EMI suppression and capacitive dropper circuits)
- PV inverters and other renewable energy inverters with stringent grid‑code EMI limits
In these circuits, X2 capacitors are typically placed between line and neutral or in series with the mains to shape the impedance seen by conducted noise. Higher AC rating and strong THB performance help maintain EMI compliance over the full lifetime, even under elevated temperature and humidity.
Technical highlights
Voltage, capacitance and form factors
The new compact variants of the B3292xU/V series:
- Are rated 350 V AC
- Offer capacitance values from 47 nF to 1.8 µF
- Use lead spacings of 15 mm and 22.5 mm, suitable for tight PCB layouts and high‑density boards
The extended B3292xU/V portfolio as a whole:
- Covers a capacitance range from 47 nF to 20 µF
- Offers lead spacings from 15 mm up to 52.5 mm, enabling scaling to higher capacitance values without changing series
This allows designers to stay within one family across multiple power levels and board form factors, simplifying qualification, sourcing, and EMC tuning.
Environmental robustness and reliability
The B3292xU/V series is designed for demanding operating conditions:
- THB test passed at +85 °C, 85% RH, at rated voltage for 1000 hours (Grade III, Test Condition B)
- Maximum operating temperature of +110 °C, supporting designs with high internal ambient or limited cooling
- AEC‑Q200 compliance, making the series suitable for automotive ECUs, charging systems, and other transportation electronics
The THB performance is particularly important for outdoor installations (EV charging, PV, metering) where moisture and high temperature combine to stress polymer film dielectrics. The specified test conditions give designers a clear benchmark for long‑term stability.
Safety and standards
The capacitors are X2 class safety components for interference suppression:
- Designed for “across the line” and series‑with‑mains positions in AC systems
- Compliant with IEC 60384‑14, including surge testing up to 2.5 kV
- High DC test voltage (1505 V, 2 s) demonstrates insulation and safety margin
Using capacitors with explicit X2 classification simplifies safety approvals for equipment, as the components are tested for operation directly on the mains under typical overvoltage categories.
Design‑in notes for engineers
When selecting X2 capacitors for EMI suppression or capacitive dropper functions, several practical aspects should be considered:
- Voltage derating: Even with a 350 V AC rating, designers should consider the maximum mains tolerance, overvoltage category, and local standards, and apply appropriate derating where necessary according to the manufacturer datasheet.
- Temperature and humidity: Applications in EV charging, PV inverters, or outdoor metering systems should take advantage of the THB Grade III data to evaluate lifetime under local climate profiles.
- Board layout: The 15 mm and 22.5 mm lead spacings of the compact versions enable shorter creepage on the PCB; however, clearance and creepage distances on the board must still meet system‑level safety standards.
- EMC tuning: For EMI filters, starting from TDK’s recommended X2 capacitance values for typical topologies can reduce tuning effort; SPICE models allow iterative optimization of capacitor values and series resistances.
- Automotive use: AEC‑Q200 compliance helps streamline qualification at OEMs and Tier‑1s, but designers should still confirm that the chosen variant meets their specific OEM test profiles and derating policies.
In many designs, combining a compact 350 V AC X2 capacitor with common‑mode chokes and surge protection devices enables a slimline EMI input filter that fits into modern, miniaturized housings without sacrificing safety margin or thermal stability.
Source
This article is based on technical information from an official TDK Electronics press release and related product information pages; engineers should refer to the current TDK datasheet and catalog entries for definitive ratings and ordering details.
