Quartz crystals are critical components used in electronic systems to provide precise timing and frequency control. In applications such as microcontrollers, communication modules, IoT devices and embedded electronics, a stable crystal oscillator ensures reliable system operation and accurate clock signals.
The Kingtronics QKT SMD Quartz Crystal series provides high-reliability SMD quartz crystal oscillators designed for modern PCB manufacturing. With compact packages and frequency ranges from 32.768 kHz to 54 MHz, the QKT series supports both low-power RTC timing circuits and high-frequency digital systems.
This article compares three key models:
- QKT-3215SMD
- QKT-3225SMD
- QKT-2016SMD
What Is an SMD Quartz Crystal?
An SMD quartz crystal is a frequency control component that uses the piezoelectric effect of quartz to generate a stable oscillation signal. When integrated into oscillator circuits within a microcontroller or processor, the crystal provides the reference clock required for digital timing operations.
Compared with traditional through-hole crystals, surface-mount quartz crystals provide several advantages including compact PCB layout, improved manufacturing efficiency, high frequency stability and reliable performance across wide operating temperature ranges.
QKT SMD Quartz Crystal Product Comparison
The Kingtronics QKT series includes multiple SMD crystal packages designed for different circuit requirements. Engineers typically select the crystal based on frequency range, PCB space and oscillator performance requirements.
| Image | Model | Package Size | Frequency Range | Key Application |
|---|---|---|---|---|
|
QKT-3215SMD | 3.2 × 1.5 mm | 32.768 kHz | RTC clocks, low-power IoT devices |
|
QKT-3225SMD | 3.2 × 2.5 mm | 12 MHz – 54 MHz | Microcontrollers and communication modules |
|
QKT-2016SMD | 2.0 × 1.6 mm | 20 MHz – 54 MHz | Compact embedded electronics |
QKT-3215SMD – 32.768 kHz RTC Crystal
The QKT-3215SMD is a 32.768 kHz tuning fork crystal commonly used in real-time clock (RTC) circuits. Its ultra-low drive power and stable frequency tolerance make it ideal for low-power electronic designs.
Typical applications include wearable electronics, smart meters, IoT devices and battery-powered embedded systems that require accurate timekeeping.
QKT-3225SMD – High Frequency AT-Cut Crystal
The QKT-3225SMD is a high-frequency AT-cut quartz crystal oscillator supporting frequencies between 12 MHz and 54 MHz. AT-cut crystals provide excellent frequency stability and temperature performance for digital circuits.
Typical applications include microcontrollers, wireless communication modules, industrial automation equipment and consumer electronics.
QKT-2016SMD – Compact High Frequency Crystal
The QKT-2016SMD is designed for compact electronics requiring high-frequency crystal performance in a small footprint. With a package size of 2.0 × 1.6 mm, it is suitable for space-limited PCB designs such as wearable electronics and wireless modules.
Its low aging characteristics and resistance to vibration make it suitable for portable devices and embedded control systems.
Typical Applications of SMD Quartz Crystals
SMD quartz crystals are widely used in electronic systems requiring precise clock signals, including microcontrollers, embedded processors, IoT devices, industrial automation systems, consumer electronics and wireless communication modules.
Selecting the correct crystal oscillator ensures stable timing performance and long-term reliability of electronic circuits.
How to Select the Right SMD Quartz Crystal
When engineers select an SMD quartz crystal, several parameters must be evaluated to ensure stable oscillator performance.
Frequency Range
The operating frequency determines the type of crystal required. For example, 32.768 kHz crystals are widely used in RTC circuits, while 12 MHz to 54 MHz crystals are common in microcontrollers and communication modules.
Load Capacitance
Load capacitance (CL) affects oscillation stability. Incorrect capacitance values may cause frequency deviation or unstable oscillator startup.
ESR (Equivalent Series Resistance)
ESR influences oscillator startup reliability. Lower ESR typically improves oscillator stability, especially in low-power embedded systems.
Package Size
PCB layout constraints must also be considered. Compact packages such as 2016 SMD crystals are suitable for wearable devices and IoT modules, while 3225 packages provide improved stability for higher frequency circuits.
Why Quartz Crystals Are Used in Microcontrollers
Most digital systems require a stable clock source. In microcontroller circuits, a quartz crystal oscillator provides the reference clock that controls instruction timing, communication protocols and data processing.
Compared with RC oscillators, quartz crystals provide higher frequency accuracy, lower temperature drift, better long-term stability and more reliable timing performance.
