Data sheet: AX5PAF4-781.250.pdf

Datasheets
AX5 Datasheet.pdf

PCN Part Status Change
Mult Devices 15/Apr/2019.pdf

Environmental Information
Abracon REACH.pdf

RoHs Status: ROHS3 Compliant

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Specifications

AX5PAF4-781.2500C Tech Specifications
Abracon LLC - AX5PAF4-781.2500C technical specifications, attributes, parameters and parts with similar specifications to Abracon LLC - AX5PAF4-781.2500C

Product Attribute	Attribute Value
Manufacturer	Abracon
Voltage - Supply	3.3V
Type	XO (Standard)
Size / Dimension	0.197" L x 0.126" W (5.00mm x 3.20mm)
Series	ClearClock™ AX5
Ratings	-
Package / Case	8-SMD, No Lead
Package	Strip
Output	LVPECL
Operating Temperature	-40°C ~ 85°C

Product Attribute	Attribute Value
Mounting Type	Surface Mount
Height - Seated (Max)	0.059" (1.50mm)
Function	Enable/Disable
Frequency Stability	±20ppm
Frequency	781.25 MHz
Current - Supply (Max)	110mA
Current - Supply (Disable) (Max)	100mA
Base Resonator	Crystal
Absolute Pull Range (APR)	-

Environmental & Export Classifications

ATTRIBUTE	DESCRIPTION
RoHs Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected
ECCN	EAR99
HTSUS	8542.39.0001

Frequently Asked Questions(FAQ)

How does the AX5PAF4-781.2500C oscillator’s frequency stability of ±20ppm impact phase noise performance in high-speed serial links, and what design considerations arise when using it for 781.25 MHz LVPECL signaling?: A ±20ppm frequency stability implies a worst-case deviation of approximately ±15.6 kHz at 781.25 MHz, which can accumulate over time or across temperature variations. In applications such as PCIe or backplane Ethernet, where clock recovery circuits rely on predictable jitter budgets, this level of stability is generally sufficient but may require careful evaluation under system-level phase noise models. The close proximity to integer multiples of common data rates (e.g., 10 Gbps) increases sensitivity to timing margin degradation, making PCB layout and power integrity critical to minimize additive jitter.

Can the AX5PAF4-781.2500C be used as a replacement for a crystal oscillator with similar frequency in a legacy design without modifying the enable/disable control logic?: Only if the legacy system supports an active-low or active-high enable pin compatible with the AX5PAF4-781.2500C’s logic levels. This oscillator features an explicit Enable/Disable function, meaning it draws significantly less current when disabled (up to 100mA max vs. 110mA active). If the previous design relied on power cycling instead of pin control, additional switching circuitry would be required to replicate the same behavior safely and efficiently.

What are the implications of mounting the AX5PAF4-781.2500C in a high-vibration environment, and how does its 8-SMD, no-lead package contribute to mechanical robustness compared to traditional SMD packages?: The 8-pin SMD, no-lead package enhances solder joint reliability under thermal cycling by minimizing stress concentration points, which improves resistance to fatigue in harsh environments. However, unlike hermetically sealed or metal-can oscillators, this component remains susceptible to microcracks from extreme mechanical shock unless proper PCB reinforcement and conformal coating are applied. For aerospace or industrial systems, supplemental strain relief or alternative packaging should be evaluated.

How does the AX5PAF4-781.2500C’s operating temperature range of -40°C to 85°C compare to commercial-grade oscillators, and what trade-offs exist in selecting it over lower-cost alternatives?: The specified range exceeds typical commercial (-20°C to +70°C) oscillators, aligning with industrial or automotive subgrades. While this enables deployment in broader ambient conditions, it does not guarantee superior long-term aging characteristics or reduced drift—those depend more on internal crystal quality than temperature alone. Cost-sensitive designs may accept slightly higher failure rates in edge cases if environmental testing confirms adequacy, but reliability-critical applications will justify the use of this device for its extended operational envelope.

What is the expected startup time for the AX5PAF4-781.2500C, and how might it affect system initialization sequences requiring rapid clock availability?: Although not explicitly stated in the datasheet, standard crystal-based oscillators like this typically exhibit startup times between 10 ms and 50 ms depending on load capacitance and drive strength. Given its ClearClock™ architecture, which optimizes crystal loading and feedback loop dynamics, startup may lean toward the lower end of this range. Designers should allow at least 30–40 ms after assertion of the enable signal before relying on stable output for downstream logic, ensuring robust system boot-up without race conditions.

How does the supply current draw of the AX5PAF4-781.2500C during operation compare to other 781.25 MHz LVPECL oscillators, and what impact does 110 mA have on power budgeting in multi-channel systems?: At 110 mA maximum, this oscillator consumes more power than some digitally controlled or low-power variants, especially those offering fractional-N or spread-spectrum features. In a multi-port application—such as a 4x SerDes transceiver—four instances could draw nearly 440 mA, necessitating attention to voltage regulator headroom and thermal dissipation. Efficient power sequencing and disabling unused channels via the enable pin become essential for maintaining overall system efficiency and meeting thermal limits.

What precautions must be taken when routing differential LVPECL outputs from the AX5PAF4-781.2500C to maintain signal integrity at 781.25 Mbps?: Differential pairs must be tightly coupled with consistent impedance (typically 100 Ω differential), matched lengths within ±5 mils, and routed away from noisy sources such as switching regulators or digital control lines. Termination resistors near the receiver end are mandatory to prevent reflections; typical values are 50 Ω to VCC/2 (often 2.5 V with 3.3 V supply). Poor termination causes overshoot, undershoot, and increased jitter, degrading link margins at this data rate.

Is there a risk of frequency pulling or modulation effects when enabling/disabling the AX5PAF4-781.2500C rapidly, and how should transient responses be managed?: Rapid transitions on the enable pin can cause temporary instability due to charge redistribution in internal bias networks and crystal settling dynamics. While the oscillator stabilizes quickly post-transition, aggressive toggling (e.g., faster than 10 µs intervals) may result in brief glitches or phase discontinuities. Designers should avoid dynamic enable modulation unless absolutely necessary, and if used, ensure transitions occur only during known safe windows (e.g., reset cycles).

How does the AX5PAF4-781.2500C’s RoHS compliance and MSL 1 rating influence handling and storage in automated assembly lines?: As a fully RoHS3-compliant device with MSL 1 classification, the AX5PAF4-781.2500C can be stored indefinitely at ambient conditions without special precautions and requires no baking prior to reflow. This simplifies inventory management and supports high-volume production workflows where shelf-life concerns are minimal, reducing logistical overhead compared to moisture-sensitive components requiring climate-controlled storage.

What alternatives exist for replacing the AX5PAF4-781.2500C in designs requiring lower power consumption or smaller form factor, and how do they compare in terms of cost-performance trade-offs?: Lower-power alternatives may include CMOS-based VCXOs or MEMS oscillators with integrated drivers, though few offer exact 781.25 MHz frequencies. MEMS devices often reduce power draw to under 50 mA and shrink size further, but introduce different noise profiles and susceptibility to shock. Trade-offs involve balancing jitter performance, startup time, and long-term reliability against power savings and board space—critical decisions that require empirical characterization rather than datasheet assumptions.

Parts with Similar Specifications

The three parts on the right have similar specifications to Abracon LLC AX5PAF4-781.2500C

Product Attribute
Part Number	AX5PAF4-781.2500	AX5PAF4-781.2500T	AX5PAF4-810.0000C	AX5PAF4-780.0000C
Manufacturer	Abracon LLC	Abracon LLC	Abracon LLC	Abracon LLC
Output	-	-	-	-
Voltage - Supply	-	-	-	-
Function	-	-	-	-
Operating Temperature	-	-40°C ~ 85°C	0°C ~ 70°C	-40°C ~ 85°C
Current - Supply (Disable) (Max)	-	-	-	-
Package	-	Tape & Reel (TR)	Tube	Tape & Reel (TR)
Size / Dimension	-	-	-	-
Series	-	-	-	-
Ratings	-	-	-	-
Base Resonator	-	-	-	-
Frequency	-	-	-	-
Type	-	-	-	-
Package / Case	-	196-LFBGA	16-DIP (0.300', 7.62mm)	64-VFQFN Exposed Pad
Mounting Type	-	Surface Mount	Through Hole	Surface Mount
Current - Supply (Max)	-	-	-	-
Frequency Stability	-	-	-	-
Absolute Pull Range (APR)	-	-	-	-
Height - Seated (Max)	-	-	-	-

AX5PAF4-781.2500C Datasheet PDF

Download AX5PAF4-781.2500C pdf datasheets and Abracon LLC documentation for AX5PAF4-781.2500C - Abracon LLC.

Datasheets: AX5 Datasheet.pdf
PCN Part Status Change: Mult Devices 15/Apr/2019.pdf
Environmental Information: Abracon REACH.pdf

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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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