C1206C226Z9VAC-TU

The KEMET C1206C226Z9VAC-TU is a surface-mount multilayer ceramic chip capacitor from the C1206 Series, utilizing Y5V (Class III) dielectric material to achieve 22µF of capacitance within the 1206 (3216 Metric) form factor. This component is part of KEMET’s commercial-grade MLCC portfolio, designed specifically for bypass and decoupling applications where volumetric efficiency takes priority over capacitance stability.

Y5V dielectric is classified by EIA as a Class III ceramic material, offering the highest capacitance density among standard MLCC dielectrics but with significant trade-offs in temperature and voltage stability. Over the operating range of -30°C to +85°C, capacitance can vary by +22% to -82%, and DC bias effects can further reduce effective capacitance by 50% or more at rated voltage. These characteristics make Y5V capacitors unsuitable for precision timing, filtering, or resonant circuits, but well-suited for bulk decoupling where the primary requirement is maximum charge storage in minimum board area.

The component features matte tin-plated terminations over a nickel barrier layer, compatible with standard lead-free reflow soldering profiles. It is fully compliant with RoHS3 and REACH regulations, and carries an MSL 1 rating, eliminating moisture sensitivity concerns during PCB assembly. Manufactured at KEMET’s facility in Mexico, this part is available in both tape & reel (7800 pcs/reel, suffix 7800) and cut tape (suffix TU) packaging formats.

1. Y5V Dielectric Mechanism: The Y5V dielectric is based on barium titanate (BaTiO₃) formulated to maximize dielectric constant (K), typically reaching 8000–15000. This extremely high permittivity enables the 22µF capacitance value in the relatively small 1206 package. However, this high-K formulation comes at the cost of pronounced ferroelectric behavior — the dielectric constant drops sharply with applied DC voltage (DC bias effect) and varies dramatically with temperature.

2. Temperature and Voltage Dependence: Over the -30°C to +85°C range, Y5V capacitance changes by +22% to -82% relative to the 25°C reference value. At the extremes, near -30°C and near +85°C, capacitance drops significantly. When DC bias voltage is applied, the effective capacitance can decrease by 40–60% or more at voltages approaching the 6.3V rating. Designers must account for these combined effects — at -30°C with full DC bias, the actual capacitance may be less than 15% of the nominal 22µF value.

3. Multilayer Stacking Architecture: Internally, the capacitor consists of many alternating layers of Y5V ceramic dielectric and nickel inner electrodes, co-fired into a monolithic structure. Each electrode pair forms a parallel-plate capacitor, and the parallel combination of all layers yields the total capacitance. The outer terminations connect to alternating inner electrode sets through wraparound contacts.

4. Decoupling Function: In power rail decoupling applications, the capacitor acts as a local charge reservoir. When a load transient demands current faster than the power supply can deliver, the stored charge in the capacitor supplies the transient current, maintaining voltage stability. The Y5V capacitor’s role is purely to provide bulk charge storage — its high ESR and ESL compared to Class I/II dielectrics limit its effectiveness at higher frequencies, where X5R/X7R or C0G capacitors are preferred.

Note: MLCCs are non-polarized components; Terminal A and Terminal B are interchangeable. The 1206 package uses wraparound terminations on opposite ends of the ceramic body. No polarity marking exists on the component.

• 3.3V/5V Power Rail Bulk Decoupling: Positioned near power pins of digital ICs to provide local charge storage for load transients. Y5V’s wide tolerance is acceptable because the decoupling function depends on charge reservoir size, not precise capacitance value
• DC-DC Converter Output Filtering: Used at the output of buck regulators in consumer electronics to supplement X5R/X7R capacitors with additional bulk capacitance at low cost
• Consumer Electronics Power Management: Power rail stabilization in cost-sensitive devices such as set-top boxes, digital photo frames, and home appliances where operating temperature remains near 25°C and Y5V performance is acceptable
• Battery-Powered Device Charge Reservoir: Local energy storage for IoT sensors and portable devices operating at 3.3V or lower, where the low operating voltage keeps Y5V DC bias effects manageable
• General-Purpose Noise Filtering: Low-frequency noise suppression on power distribution networks where precise capacitance values and tight temperature stability are not design requirements