The Knowles Syfer 2211YA255P60DKTSYX represents a precision Class 1 ceramic capacitor engineered for safety-critical and automotive-qualified applications. This FlexiCap™ series component delivers 5.6 pF capacitance with an exceptionally tight ±0.5pF absolute tolerance, paired with a 250VAC voltage rating that addresses Y-capacitor suppression requirements in power line filtering and EMI mitigation circuits.
Built on C0G (NP0, Class 1B) dielectric technology, this capacitor exhibits zero temperature coefficient across its -55°C to 125°C operating range, maintaining capacitance stability within ±30 ppm/°C. This temperature-stable characteristic proves particularly valuable in precision timing circuits, RF filtering stages, and sensor interface applications where capacitance drift directly impacts measurement accuracy or signal integrity. The C0G dielectric also provides superior voltage linearity and Q factor compared to Class 2 alternatives, with typical dissipation factors below 0.1% at 1 MHz.
The 250VAC rating combined with X1/Y2 safety approvals positions this component for line-to-line and line-to-ground filtering in mains-connected equipment. X1 classification allows operation across 250VAC phase-to-phase connections without additional derating, while Y2 certification supports reinforced insulation requirements with basic insulation voltage ratings. These dual certifications enable streamlined compliance with IEC 60950, IEC 62368, and related safety standards common in industrial controls, appliance inverters, and automotive onboard charging systems.
AEC-Q200 qualification extends this component's applicability to automotive electronics operating under extended temperature cycling, mechanical shock, and humidity exposure conditions defined by Automotive Electronics Council standards. The soft termination feature specifically addresses reliability concerns in boardflex-sensitive applications, where traditional rigid solder joints may crack under PCB bending or thermal expansion. This flexible termination layer accommodates substrate movement without compromising electrical connection, reducing field failure rates in under-hood automotive environments and portable industrial equipment.
Compliance with DC Annex H and Humidity 3B Annex I requirements demonstrates validated performance under sustained high-voltage DC bias and humidity exposure, addressing common failure modes in safety capacitor applications. The component's 2211 (5728 Metric) surface mount package measures 0.224" × 0.110" (5.70mm × 2.80mm), providing a balance between voltage isolation requirements and board space efficiency in compact power supply layouts.
The combination of low capacitance, tight tolerance, and high voltage rating makes this component suitable for precision EMI filter designs where exact cutoff frequencies must be maintained, voltage divider networks in high-voltage sensing circuits, and DC blocking applications in automotive communication interfaces. MLCC construction ensures long-term reliability compared to film alternatives at this capacitance level, while maintaining compatibility with standard reflow soldering profiles up to MSL 1 classification limits.
Replacing Knowles Syfer 2211YA255P60DKTSYX When a Safety-Rated 5.6 pF MLCC Becomes Hard to Source
Finding an equivalent for Knowles Syfer 2211YA255P60DKTSYX is not a simple capacitance-and-package match. This component is a safety-certified, high-voltage, C0G/NP0 surface-mount ceramic capacitor with soft termination, automotive qualification, and X1/Y2 ratings. A replacement must be checked against electrical behavior, creepage and clearance requirements, board-flex reliability, safety agency recognition, and assembly compatibility.
Potential replacement and comparison candidates include:
| Manufacturer | Candidate Part Number | Replacement Position |
|---|---|---|
| Knowles Syfer | 2211YA255P60DKTSYX | Original / direct reference part |
| KEMET | CAS21C5R6DARAC7800 | Safety-rated SMD MLCC candidate |
| Vishay | VJ2220A5R6DXUSTX1 | Safety-certified SMD MLCC candidate |
| Johanson Dielectrics | 502R29W5R6CV4E | High-voltage safety capacitor candidate |
| Murata | GA352DR7GF5R6KW01L | Safety-certified ceramic capacitor candidate |
The closest substitute is one that preserves the 5.6 pF capacitance, C0G/NP0 dielectric stability, 250 VAC safety-related rating, and surface-mount assembly format. However, agency rating details, package footprint differences, and termination design often determine whether a part is a true drop-in replacement or only a redesign candidate.
What Knowles Syfer 2211YA255P60DKTSYX Requires from an Equivalent Capacitor
Knowles Syfer 2211YA255P60DKTSYX is a FlexiCap™ series ceramic capacitor designed for safety, automotive, and board-flex-sensitive applications. Its main electrical value is 5.6 pF with ±0.5 pF tolerance, using C0G/NP0 dielectric material. This dielectric choice gives low capacitance drift with temperature, voltage, and time, which matters in EMI filtering, high-frequency coupling, line-to-ground suppression, and precision RF-related safety networks.
Key replacement-relevant characteristics include:
| Parameter | Knowles Syfer 2211YA255P60DKTSYX | Why It Matters for Replacement |
|---|---|---|
| Capacitance | 5.6 pF | Affects impedance, filtering frequency, signal loading, and leakage path behavior |
| Tolerance | ±0.5 pF | More precise than common ±5% or ±10% alternatives at low capacitance values |
| Voltage Rating | 250 VAC | Replacement must match the AC safety use case, not only DC voltage rating |
| Dielectric | C0G/NP0 | Needed where capacitance stability and low loss are required |
| Safety Ratings | X1, Y2 | Determines suitability across-line or line-to-earth safety applications |
| Automotive Rating | AEC-Q200 | Relevant for automotive electronics and harsh-environment qualification |
| Package | 2211 / 5728 metric | Footprint compatibility must be verified against pad geometry |
| Termination | Soft termination / FlexiCap™ | Reduces cracking risk under board flex and thermal-mechanical stress |
| Operating Temperature | -55°C to +125°C | Replacement must maintain rating over the application temperature range |
| Packaging | Tape & Reel | Supports automated SMT assembly |
The combination of X1/Y2 safety rating, C0G/NP0 dielectric, AEC-Q200 qualification, and soft termination narrows the replacement field. A standard 5.6 pF MLCC in the same approximate size may be electrically close at low voltage, but it may not be acceptable for safety-certified circuits. Conversely, a safety capacitor with the right rating but a larger footprint or looser tolerance may require layout or circuit validation.
Typical applications include automotive EMI suppression, safety isolation filtering, high-voltage signal coupling, line-to-ground noise control, and circuits exposed to board bending. In these use cases, the replacement decision should consider both normal electrical performance and abnormal-condition behavior required by safety standards.
Candidate Replacements for Knowles Syfer 2211YA255P60DKTSYX and How They Fit the Original Design
The table below compares candidate replacement parts from an engineering suitability perspective. These parts should be treated as candidates that require datasheet, safety approval, footprint, and qualification confirmation before release into production.
| Manufacturer | Part Number | Key Specifications | Product Features | Typical Applications | Why It Can Replace the Original Part | Main Differences or Limitations | Recommended Usage |
|---|---|---|---|---|---|---|---|
| Knowles Syfer | 2211YA255P60DKTSYX | 5.6 pF, ±0.5 pF, 250 VAC, C0G/NP0, 2211 package, X1/Y2, AEC-Q200 | FlexiCap™ soft termination, high-voltage safety rating, humidity and DC Annex compliance, tape and reel | Automotive EMI filtering, safety-related line filtering, board-flex-sensitive assemblies | Baseline component with matching electrical, mechanical, safety, and qualification profile | Availability, lead time, or sourcing constraints may drive replacement evaluation | Preferred option when no redesign or requalification is desired |
| KEMET | CAS21C5R6DARAC7800 | 5.6 pF class, safety-rated SMD MLCC, C0G-type dielectric option, AC safety application family | Safety-certified surface-mount ceramic capacitor family, automotive-oriented options depending on suffix | AC mains filtering, EMI suppression, industrial and automotive control electronics | Similar low-capacitance safety MLCC function; suitable when safety agency rating and capacitance match the original requirement | Footprint, agency rating class, termination construction, and tolerance must be checked against the Knowles Syfer part | Good candidate where a safety-rated SMD MLCC is required and layout validation is possible |
| Vishay | VJ2220A5R6DXUSTX1 | 5.6 pF class, 2220-size safety-certified MLCC family, C0G/NP0-type option depending on ordering code | Safety-certified MLCC construction, robust ceramic capacitor platform | EMI suppression, safety filtering, power electronics interfaces | Can support similar safety capacitor roles where 5.6 pF and safety approval are required | 2220 body may differ from 2211 footprint; tolerance and termination flexibility may not match FlexiCap™ | Suitable for redesigns or layouts that can accept footprint adjustment |
| Johanson Dielectrics | 502R29W5R6CV4E | 5.6 pF class, high-voltage ceramic safety capacitor candidate | High-voltage ceramic construction, safety-capacitor product family | Line-to-ground filtering, RF noise shunting, industrial equipment | Useful where high-voltage ceramic safety behavior and low capacitance are needed | Package style, agency approvals, and SMT footprint may differ; not automatically a drop-in part | Best for new design validation or controlled PCB layout revisions |
| Murata | GA352DR7GF5R6KW01L | 5.6 pF class, safety-certified ceramic capacitor family candidate | Established ceramic capacitor manufacturing, safety-oriented series options | Consumer, industrial, and power-interface EMI control | May provide a compatible safety capacitor function if voltage, rating, and dielectric requirements align | Capacitance tolerance, dielectric code, package size, and certification details require direct datasheet verification | Appropriate when supply chain diversity is needed and electrical margins allow validation testing |
When evaluating KEMET CAS21C5R6DARAC7800, Vishay VJ2220A5R6DXUSTX1, Johanson Dielectrics 502R29W5R6CV4E, and Murata GA352DR7GF5R6KW01L, the first screening step should not be price. It should be whether the part carries the required X/Y safety approval for the intended circuit location. A capacitor used from line to protective earth has different approval expectations than a capacitor used only in a low-energy EMI path.
The second check is mechanical. Knowles Syfer 2211YA255P60DKTSYX uses a 2211 / 5728 metric footprint with soft termination. If the replacement uses 2220 or another nearby package, pad overlap may appear acceptable, but solder fillet geometry, creepage distance, assembly yield, and flex cracking risk may change.
The third check is capacitance precision. At 5.6 pF, a tolerance difference of ±0.5 pF versus ±5% or ±10% may alter high-frequency impedance or tuning behavior. In simple EMI bypass applications this may be acceptable; in impedance-sensitive circuits it may require measurement.
Engineering Trade-Offs When Comparing Knowles Syfer 2211YA255P60DKTSYX Replacement Options
A replacement decision should balance safety certification, electrical performance, mechanical fit, qualification status, and procurement risk. The following comparison focuses on practical substitution decisions rather than only nominal datasheet values.
| Evaluation Factor | Knowles Syfer 2211YA255P60DKTSYX | KEMET CAS21C5R6DARAC7800 | Vishay VJ2220A5R6DXUSTX1 | Johanson Dielectrics 502R29W5R6CV4E | Murata GA352DR7GF5R6KW01L |
|---|---|---|---|---|---|
| Electrical Compatibility | Baseline 5.6 pF, ±0.5 pF, C0G/NP0, 250 VAC | Potentially close if capacitance, tolerance, dielectric, and AC rating match | Good candidate if C0G/NP0 and safety rating align | Suitable for low-capacitance high-voltage filtering if rating is confirmed | Suitable if dielectric and rated voltage meet the original circuit requirement |
| Safety Rating Fit | X1/Y2 stated for the original part | Must confirm X1/Y2 or equivalent approval for exact order code | Must confirm exact safety class and agency file | Must verify exact safety approval and use category | Must verify safety class for the exact part number |
| Mechanical Compatibility | 2211 / 5728 metric reference footprint | May be close, but package drawing must be compared | 2220-style body may require pad/layout review | Package may differ depending on series construction | Package compatibility must be checked against PCB land pattern |
| Board-Flex Reliability | Soft termination / FlexiCap™ supports flex-sensitive designs | Depends on termination option | Depends on termination system and ceramic body size | Must be assessed for board strain environment | Depends on series and termination construction |
| Capacitance Stability | C0G/NP0 gives stable behavior over temperature and voltage | Acceptable if C0G-type dielectric is confirmed | Acceptable if C0G/NP0 option is used | Depends on dielectric option | Depends on dielectric code and operating bias |
| Automotive Suitability | AEC-Q200 stated | Check automotive qualification for exact suffix | Check AEC-Q200 availability for exact part | Automotive use may require additional validation | Check automotive qualification and PPAP availability if needed |
| Assembly Impact | Tape and reel SMT assembly compatible | Likely SMT-compatible; reel format should be confirmed | SMT-compatible but footprint may differ | May require assembly profile and land-pattern review | SMT-compatible if package and reel options align |
| Reliability Considerations | Designed for safety, humidity, high voltage, and flex environments | Strong candidate if safety and termination features align | Larger body may offer spacing benefits but may increase flex sensitivity | High-voltage focus can be beneficial, but mechanical behavior must be tested | Strong supplier base; exact qualification must match the application |
| Cost and Availability | May be constrained by stock or lead time | Useful for second-source strategy if approved | Useful where Vishay supply chain is preferred | Useful for specialized high-voltage sourcing | Useful for multi-source purchasing strategy |
| Best Fit Scenario | Direct replacement or continued production without redesign | Alternate source after datasheet and approval match | Redesign or layout-tolerant replacement | New validation path for high-voltage filtering | Supply-chain diversification with controlled qualification |
| Main Limitation | Single-source or availability exposure | Exact equivalence depends on suffix-level data | Possible footprint and termination mismatch | Not automatically drop-in | Exact safety and dielectric details must be verified |
For a direct replacement path, Knowles Syfer 2211YA255P60DKTSYX remains the benchmark because it combines the required 5.6 pF value, C0G/NP0 dielectric, 250 VAC rating, X1/Y2 safety classification, AEC-Q200 qualification, and soft termination in the specified 2211 package.
For a second-source path, KEMET CAS21C5R6DARAC7800 is typically the first type of candidate to examine because it belongs to a safety-rated SMD MLCC category. The main work is suffix verification: tolerance, dielectric, voltage rating, agency certification, and termination construction must all be confirmed.
Vishay VJ2220A5R6DXUSTX1 may be attractive where a safety-certified MLCC platform is acceptable and the PCB can tolerate a footprint review. It is less suitable as a blind drop-in substitute if the original 2211 land pattern and FlexiCap™ behavior are required.
Johanson Dielectrics 502R29W5R6CV4E is more appropriate when the design priority is high-voltage ceramic safety behavior and the project can support qualification testing. It should be treated as a candidate for controlled redesign rather than a direct equivalent without mechanical confirmation.
Murata GA352DR7GF5R6KW01L can support sourcing diversification if the exact part meets the needed safety class, dielectric stability, and package requirements. It is most suitable where supplier approval, agency documentation, and layout verification can be completed before production release.
For replacement part availability, cross-reference support, and quotations, obtain pricing through the professional electronic components website IC-Components.com or email Info@IC-Components.com.
