SII Begins Mass Production of the World’s Smallest (1.0 × 0.8 × 0.32mm) Tuning-Fork Crystal Resonator “SC-10S”

Seiko Instruments Inc. (President: Yoichi Endo; Headquarters: Chiba City, Chiba Prefecture; hereinafter “SII”) will begin mass production of the “SC-10S” (32.768kHz), the world’s smallest* tuning-fork crystal resonator measuring 1.0 × 0.8mm, starting in April 2026.
*Based on SII research as of November 2025.

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[Background of Development]
SII has already been mass-producing the “SC-12S” (32.768kHz), one of the world’s smallest tuning-fork crystal resonators at 1.2 × 1.0mm. As wearable devices such as smart rings and smartwatches, as well as IoT devices, continue to become smaller, the electronic components built into these devices are increasingly required to support high-density mounting, low power consumption, and high performance. To meet these needs, SII leveraged its proprietary photolithography technology to develop and mass-produce the world’s smallest tuning-fork crystal resonator, the “SC-10S,” which achieves a 33% reduction in mounting area compared to existing models (1.0 × 0.8 × 0.32mm).

[Main Features]
1. World’s Smallest Size
Using SII’s proprietary photolithography technology, which forms fine patterns on quartz wafers, the SC-10S achieves high-precision processing at the world’s smallest size for a 32.768kHz tuning-fork crystal resonator: 1.0 × 0.8 × 0.32mm.

2. Low ESR (90 kΩ max.)
Miniaturization typically leads to an increase in ESR (Equivalent Series Resistance). However, through SII’s proprietary design and manufacturing technologies, the SC-10S maintains a low ESR of 90kΩ max., equivalent to that of existing models.

3. High Shock Resistance and Frequency Stability
The SC-10S ensures excellent frequency stability even in environments subjected to shock or vibration, delivering highly reliable operation.

[Main specifications]
Item		Specification
Dimensions		1.0 x 0.8 x 0.32mm
Nominal Frequency		32.768kHz
Frequency Tolerance		±20×10-6
Turnover Temperature		+25±5°C
Parabolic Coefficient		(-0.036±10%)×10-6/°C2
Load Capacitance		4pF, 6pF, 7pF, 9pF, 12.5pF
Motional Resistance (ESR)		90kΩ max.
Absolute Maximum Drive Level		0.3μW max.
Recommended Drive Level		0.1μW typ.
Shunt Capacitance		1.1pF
Frequency Ageing		±5×10-6/year
Operating Temperature Range		-40 to +85°C
Storage Temperature Range		-55 to +125°C

[Main Applications]
Smart rings, smartwatches, smart tags, hearing aid
Communication modules such as Bluetooth and LPWA
Clock frequency source for RTCs (Real-Time Clocks)
Sub-clock for various microcontrollers

[Production Schedule]
Sample Shipments Begin: December 2025
Mass Production Start: April 2026

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