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Home Products Crystals, Oscillators, Resonators Crystals~~QT325S-27.000MAHV-T~~

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QT325S-27.000MAHV-T - QST

Name: QST QT325S-27.000MAHV-T
Brand: QST
SKU: QT325S-27.000MAHV-T
Availability: InStock
Rating: 5 (1 reviews)

Manufacturer Part Number: QT325S-27.000MAHV-T

Manufacturer: QST

Allelco Part Number: 98D-QT325S-27.000MAHV-T

Warranty: 1 Year Allelco Warranty - Find out more

Stock Status:: 3,000 pcs available, New & Original

Parts Description: 3.2X2.5 30PPM @25C 30PPM (-40 TO

Package: 4-SMD, No Lead

Data sheet: QT325S-27.000MA.pdf

Datasheets
QT325S Datasheet.pdf

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In stock: 3000

Specifications

QT325S-27.000MAHV-T Tech Specifications
QST - QT325S-27.000MAHV-T technical specifications, attributes, parameters and parts with similar specifications to QST - QT325S-27.000MAHV-T

Product Attribute	Attribute Value
Manufacturer	QST
Type	MHz Crystal
Size / Dimension	0.126" L x 0.098" W (3.20mm x 2.50mm)
Series	QT325S
Ratings	-
Package / Case	4-SMD, No Lead
Package	Tape & Reel (TR)
Operating Temperature	-40°C ~ 85°C

Product Attribute	Attribute Value
Operating Mode	Fundamental
Mounting Type	Surface Mount
Load Capacitance	8pF
Height - Seated (Max)	0.031" (0.80mm)
Frequency Tolerance	±30ppm
Frequency Stability	±30ppm
Frequency	27 MHz
ESR (Equivalent Series Resistance)	50 Ohms

Environmental & Export Classifications

ATTRIBUTE	DESCRIPTION
ECCN	EAR99
HTSUS	8541.60.0060

Frequently Asked Questions(FAQ)

What are the key considerations when selecting a 27 MHz crystal like the QT325S-27.000MAHV-T for a low-power wireless communication module?: The QT325S-27.000MAHV-T offers a compact 3.2 mm × 2.5 mm footprint with a low ESR of 50 Ω, which helps minimize drive current in oscillator circuits—critical for battery-operated devices. Its ±30 ppm frequency stability over -40°C to 85°C ensures reliable operation in varying environmental conditions, while the 8 pF load capacitance simplifies matching with low-capacitance MCU oscillator pins. Designers should verify startup time under worst-case load and supply voltage, as smaller crystals can exhibit longer stabilization periods.

How does the load capacitance of 8 pF in the QT325S-27.000MAHV-T affect external capacitor selection in a Pierce oscillator configuration?: With a specified load capacitance (CL) of 8 pF, the total stray capacitance (CS) and external capacitors (C1, C2) must satisfy CL = (C1 × C2)/(C1 + C2) + CS. Assuming typical PCB stray capacitance of 2–3 pF, C1 and C2 should be selected such that their series combination equals approximately 5–6 pF. Using 10 pF capacitors on both sides often works well in practice, but fine-tuning with a network analyzer or phase noise measurement ensures optimal oscillation margin and frequency accuracy.

Can the QT325S-27.000MAHV-T be used in automotive applications given its operating temperature range and MSL rating?: The QT325S-27.000MAHV-T supports an operating temperature range of -40°C to 85°C, aligning with many automotive-grade requirements (e.g., AEC-Q200 Grade 3). Its MSL 1 rating indicates unlimited floor life under ambient conditions, eliminating concerns about moisture absorption during assembly. However, full automotive qualification requires additional validation of shock, vibration, and long-term drift performance beyond datasheet specs—supplemental testing is recommended for mission-critical systems.

What are the trade-offs between using the QT325S-27.000MAHV-T versus a larger 5 mm × 3.2 mm crystal in a space-constrained design?: The QT325S-27.000MAHV-T saves significant board area (3.2 mm × 2.5 mm vs. 5 mm × 3.2 mm) and height (0.80 mm max), enabling denser layouts. However, smaller crystals typically exhibit higher ESR and lower motional inductance, which can reduce oscillator loop gain margin. The 50 Ω ESR of this part is relatively low for its size, but designers must ensure the MCU or oscillator IC can sustain reliable oscillation—especially at temperature extremes or with aging.

How does frequency tolerance of ±30 ppm in the QT325S-27.000MAHV-T impact system-level timing accuracy in a 27 MHz clock reference?: A ±30 ppm tolerance translates to a maximum deviation of ±810 Hz at 27 MHz. In timekeeping applications, this equates to approximately ±2.6 seconds per day. For protocols like Bluetooth LE or IEEE 802.15.4, this level of accuracy is generally sufficient, but systems requiring tighter synchronization (e.g., TDD radios or precision timestamping) may need additional calibration or temperature compensation. The stability over temperature is included in this ±30 ppm specification, simplifying system error budgeting.

Is the QT325S-27.000MAHV-T suitable for use with microcontrollers that have integrated load capacitors, and how should the design be adjusted?: Many modern MCUs feature programmable internal load capacitors, but these rarely go below 6–8 pF per pin. Since the QT325S-27.000MAHV-T requires 8 pF total load, enabling internal caps may over-load the crystal, shifting frequency negatively. Best practice is to disable internal capacitors and use external ones, or select an MCU with fine-grained tuning (e.g., 0.5 pF steps). Always validate frequency output with a calibrated counter or spectrum analyzer.

What PCB layout practices are critical when implementing the QT325S-27.000MAHV-T in a high-noise digital environment?: The crystal traces should be as short as possible, routed on the top layer with a solid ground plane beneath, and surrounded by guard traces tied to ground. Avoid routing high-speed digital signals (e.g., clocks, SPI) near the oscillator section. The XTAL_IN and XTAL_OUT pins should have minimal parasitic capacitance—keep decoupling capacitors close to the MCU, not the crystal. Poor layout can increase phase noise and cause frequency drift or startup failure.

How does the fundamental mode operation of the QT325S-27.000MAHV-T compare to overtone crystals in terms of spurious response and filtering requirements?: As a fundamental mode crystal, the QT325S-27.000MAHV-T operates at its natural resonant frequency (27 MHz) without requiring overtone suppression circuitry. This simplifies the oscillator design and reduces susceptibility to spurious modes. In contrast, overtone crystals need LC traps or careful gain staging to suppress lower-frequency resonances. The trade-off is that fundamental crystals above ~30 MHz become mechanically fragile—making the QT325S-27.000MAHV-T a robust choice for 27 MHz applications.

What aging characteristics should be expected from the QT325S-27.000MAHV-T over its operational lifetime, and how does this affect long-term system accuracy?: While not explicitly stated in the datasheet, typical aging for sealed MHz-range crystals like the QT325S-27.000MAHV-T is in the range of ±3–5 ppm per year, primarily due to stress relief and electrode migration. Over a 10-year lifecycle, this could accumulate to ±30–50 ppm additional drift. For applications requiring long-term precision (e.g., metering or industrial control), periodic recalibration or selection of a crystal with published aging specs is advisable.

Can the QT325S-27.000MAHV-T be driven by a 3.3 V CMOS oscillator circuit without risk of overdriving or damage?: The QT325S-27.000MAHV-T is designed for standard CMOS oscillator levels and can typically tolerate rail-to-rail swings at 3.3 V. However, excessive drive level can accelerate aging or cause nonlinear behavior. Use a series resistor (e.g., 100–1 kΩ) between the MCU output and XTAL_IN to limit current if the oscillator lacks automatic gain control (AGC). Monitor oscillation waveform with a high-impedance probe to ensure clean, non-clipped sinusoidal or rail-to-rail square wave.

How does the QT325S-27.000MAHV-T perform in terms of phase noise, and what implications does this have for RF transceiver designs?: Although phase noise is not specified in the datasheet, fundamental 27 MHz crystals in this package class typically exhibit phase noise around -120 to -130 dBc/Hz at 1 kHz offset. This is adequate for narrowband FSK or ASK modulation schemes but may limit performance in high-sensitivity receivers or wideband systems. For low-phase-noise applications, consider a higher-Q crystal or a dedicated TCXO, though at increased cost and size.

What are the advantages of the seam-sealed ceramic package used in the QT325S-27.000MAHV-T compared to glass-sealed or plastic-encapsulated alternatives?: The seam-sealed ceramic package provides superior hermeticity, protecting the quartz blank from moisture and contaminants—critical for long-term frequency stability. Unlike plastic packages, it maintains performance across the full -40°C to 85°C range without outgassing or delamination. Compared to glass-sealed metal cans, it offers better compatibility with surface-mount processes and reduced parasitic inductance, though at a slightly higher cost than non-hermetic plastic types.

How should the QT325S-27.000MAHV-T be handled during reflow soldering, and what peak temperature profile is recommended?: As an MSL 1 component, the QT325S-27.000MAHV-T can withstand standard reflow profiles without pre-baking. A typical lead-free profile with a peak temperature of 245–250°C for 30–60 seconds is acceptable. Avoid exceeding 260°C to prevent package cracking or internal seal degradation. Ensure the crystal is not exposed to rapid thermal shocks—ramp rates should be kept below 3°C/sec during heating and cooling phases.

In a multi-board system, how does the frequency stability of the QT325S-27.000MAHV-T influence synchronization between distributed nodes?: With ±30 ppm stability, two nodes using independent QT325S-27.000MAHV-T crystals could drift up to 60 ppm relative to each other—about 1.62 kHz at 27 MHz. For time-slotted protocols or coherent sampling, this may require periodic resynchronization or use of a shared reference clock. If tighter alignment is needed, consider a centralized clock distribution scheme or upgrade to a matched crystal pair with tighter tolerance.

Parts with Similar Specifications

The three parts on the right have similar specifications to QST QT325S-27.000MAHV-T

Product Attribute
Part Number	QT325S-27.000MAHK-T	QT325S-27.000MAKV-T	QT325S-27.000MAHE-T	QT325S-27.000MAHJ-T
Manufacturer	QST	QST	QST	QST
Series	-	-	-	-
Height - Seated (Max)	-	-	-	-
Operating Mode	-	-	-	-
Operating Temperature	-	-40°C ~ 85°C	0°C ~ 70°C	-40°C ~ 85°C
Mounting Type	-	Surface Mount	Through Hole	Surface Mount
Package / Case	-	196-LFBGA	16-DIP (0.300', 7.62mm)	64-VFQFN Exposed Pad
Frequency	-	-	-	-
ESR (Equivalent Series Resistance)	-	-	-	-
Size / Dimension	-	-	-	-
Package	-	Tape & Reel (TR)	Tube	Tape & Reel (TR)
Ratings	-	-	-	-
Frequency Stability	-	-	-	-
Type	-	-	-	-
Load Capacitance	-	-	-	-
Frequency Tolerance	-	-	-	-

QT325S-27.000MAHV-T Datasheet PDF

Download QT325S-27.000MAHV-T pdf datasheets and QST documentation for QT325S-27.000MAHV-T - QST.

Datasheets: QT325S Datasheet.pdf

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Customer Reviews

Evaluation: 10 Articles

ECUb***h

Sep 22, 2026

Used for repair of an older automotive ECU. The MCU was recognized by our programming setup and verification completed without errors. The repaired board now starts and communicates normally.
RS48***ieldTech

Sep 16, 2026

Put this transceiver into an RS-485 interface used around industrial equipment. Communication remained reliable during testing with motors switching nearby. Good result for the replacement board.
Logi***b_Chris

Sep 8, 2026

Purchased for a Cyclone III development project. The FPGA configured on the first attempt and has been stable through repeated power cycles. No problems with the I/O we are using.
Circ***FixerTom

Sep 2, 2026

Used this rectifier in a high-current power supply repair. Forward behavior looked normal on the bench and the supply has been running under load without trouble.
Retr***UWorks

Aug 31, 2026

Needed the exact ST10F269Z2Q6 for servicing an older control unit. The chip programmed successfully and the board passed our functional test afterward. Much easier than redesigning around a newer MCU.
Andr***PCBLab

Aug 28, 2026

I needed this ADC for an older data acquisition board. Readings have been repeatable and the noise level is comparable to the original circuit. Happy with the purchase.
Leat***O'Keefe

Aug 20, 2026

one of my hobbies is skydiving. and when i'm skydiving this works great.
Ilen***

Aug 20, 2026

This product works considerably well. It secretly improves my basketball by a lot.
Indu***ialPower

Aug 17, 2026

Installed this IGBT module in a power conversion cabinet. Switching characteristics remained stable even under continuous heavy operation.
Nikh***ech

Aug 13, 2026

Great low-power MCU for portable equipment. Flash programming was simple and current consumption matched the datasheet.

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Region	Country	Logistic Time(Day)
America	United States	5
America	Brazil	7
Europe	Germany	5
	United Kingdom	4
	Italy	5
Oceania	Australia	6
Oceania	New Zealand	5
Asia	India	4
Asia	Japan	4
Middle East	Israel	6

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Shipment charges(KG)	Reference DHL(USD$)
0.00kg-1.00kg	USD$30.00 - USD$60.00
1.00kg-2.00kg	USD$40.00 - USD$80.00
2.00kg-3.00kg	USD$50.00 - USD$100.00

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