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Texas Instruments LMK61E0-156M25SIAR
- Part No.:
- LMK61E0-156M25SIAR
- Manufacturer:
- Texas Instruments
- Category:
- Oscillators
- Package:
- 6-SMD Module
- Datasheet:
-
LMK61E0-156M25SIAR.pdf
- Description:
- SILIC OSC XO 156.2500MHZ LVPECL
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LMK61E0-156M25SIAR from Texas Instruments is an ultra-low-jitter LVPECL oscillator generating a fixed 156.25 MHz reference clock with ±25 ppm total frequency tolerance, 90 fs RMS phase jitter (typical), and robust –70 dBc PSRR. It operates from a single 3.3 V supply in industrial temperature range (–40°C to +85°C) and serves as a high-stability timing source for FPGA and processor clocking in telecom infrastructure.
For engineers reviewing the LMK61E0-156M25SIAR datasheet, LMK61E0-156M25SIAR pinout, LMK61E0-156M25SIAR application, or LMK61E0-156M25SIAR equivalent, key selection criteria include differential LVPECL output compatibility, sub-100-fs jitter performance at 156.25 MHz, factory-programmed frequency stability, and 7 mm × 5 mm QFM package integration into high-speed serial link timing chains.
Technical Context
The LMK61E0-156M25SIAR integrates a high-performance PLL-based oscillator core with internal power conditioning to suppress supply noise, enabling clean clock generation without external filtering. Its LVPECL output stage delivers 700–1200 mV differential swing up to 1 GHz with 120–200 ps rise/fall times and 45–55% duty cycle.
It features an LVCMOS OE input with internal pull-up, allowing deterministic output enable/disable control with 50 µs response time. The device is pre-programmed for 156.25 MHz LVPECL operation and supports no external configuration - eliminating startup delay variability and simplifying system-level timing validation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Frequency | 156.25 MHz - factory-programmed, exact value required for Ethernet PHY, PCIe Gen2/3, and SONET/SDH line-rate synchronization. |
| Jitter (RMS) | 90 fs typical (12 kHz–20 MHz integration band) - enables <0.1 UI jitter margin in 10G+ serial links and meets stringent SerDes eye-opening requirements. |
| Output Format | LVPECL - provides fast edge rates and high noise immunity for point-to-point clock distribution over controlled-impedance traces. |
| Frequency Tolerance | ±25 ppm - includes initial calibration, temperature drift (–40°C to +85°C), supply variation, solder reflow, and 5-year aging - ensures long-term system timing compliance. |
| Supply Voltage | 3.3 V ±5% - compatible with standard logic rails and simplifies power delivery network design versus dual-supply oscillators. |
| PSRR | –70 dBc at 50 kHz–1 MHz ripple - rejects switching noise from adjacent DC/DC converters without additional LDO filtering. |
| Package | 6-pin QFM (7.0 mm × 5.0 mm) - industry-standard 7050 footprint enabling drop-in replacement of legacy XOs and compatibility with automated SMT assembly. |
Pinout & Package
LMK61E0-156M25SIAR uses a 6-pin QFM (SIA) package measuring 7.0 mm × 5.0 mm with exposed thermal pad. Pin 1 is marked by dot; pins are numbered counter-clockwise from top-left in top view.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | LVCMOS Input | Output Enable with internal pull-up; drives outputs to high-impedance when low - enables dynamic clock gating without external logic. |
| 2 (NC) | No Connect | Unbonded pin; must remain unconnected per TI specification - avoids unintended coupling or EMI paths. |
| 3 (GND) | Ground Reference | Primary analog ground return; requires ≥3 thermal vias to inner ground plane for thermal dissipation and low-impedance return path. |
| 4 (OUTN) | Differential Output | Inverted LVPECL output; paired with OUTP to form 100-Ω differential transmission line interface - minimizes common-mode noise. |
| 5 (OUTP) | Differential Output | Non-inverted LVPECL output; forms complementary pair with OUTN - enables AC-coupled termination to 100 Ω or 50 Ω per leg. |
| 6 (VDD) | Analog Power Supply | 3.3 V analog rail; requires local 10 µF / 1 µF / 0.1 µF decoupling - critical for maintaining sub-100-fs jitter performance. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low jitter | 90 fs RMS typical at 156.25 MHz - directly reduces bit error rate in high-speed serial receivers and improves ADC sampling accuracy. |
| High PSRR | –70 dBc supply noise rejection - eliminates need for dedicated low-noise LDO, reducing BOM count and board area. |
| Factory-programmed frequency | Exact 156.25 MHz LVPECL output - removes external programming components and configuration firmware overhead. |
| Industrial temperature range | –40°C to +85°C operation - supports deployment in base station radios, network switches, and industrial controllers without derating. |
| Pin-compatible packaging | 7 mm × 5 mm QFM matches industry-standard 7050 XO footprint - enables direct mechanical and layout replacement of legacy oscillators. |
Applications
| 10G Ethernet Line Cards | FPGA-Based Test Equipment |
|---|---|
Use Scenario: High-density 10GBASE-R switch fabric requiring synchronous clocking across multiple PHYs and MACs. IC Role / Device Role / Timing Role: Primary reference oscillator providing 156.25 MHz LVPECL clock to Ethernet PHYs and SerDes blocks. Use Value: Sub-100-fs jitter ensures >25 dB SNR margin in 10G NRZ signaling and maintains IEEE 802.3ae jitter compliance across temperature and voltage. |
Use Scenario: Modular PXI or AXI-based signal generator with programmable sample clocks up to 1 GSPS. IC Role / Device Role / Timing Role: Low-phase-noise master clock source for high-resolution DACs and real-time digital upconverters. Use Value: –165 dBc/Hz phase noise floor at 10 MHz offset enables <–95 dBc spurious-free dynamic range in RF synthesis applications. |
| Optical Transport Network (OTN) BBU | PCIe Gen3 Server Backplanes |
Use Scenario: Baseband unit in CPRI/eCPRI fronthaul systems requiring precise 156.25 MHz clock alignment between radio and baseband units. IC Role / Device Role / Timing Role: Stratum-3-equivalent timing reference for JESD204B converter interfaces and FPGA-based DSP cores. Use Value: ±25 ppm total stability over life ensures sustained frame synchronization and eliminates periodic resync events in distributed timing architectures. |
Use Scenario: Clocking for PCIe Gen3 root complex and endpoint devices on enterprise server motherboards. IC Role / Device Role / Timing Role: Differential LVPECL clock source meeting PCIe Gen3 jitter budget (≤1.0 ps RMS) at 100 MHz fundamental with 156.25 MHz derived clocks. Use Value: 90 fs RMS jitter at 156.25 MHz translates to <0.5 ps RMS at 100 MHz after divider-based scaling - exceeds PCIe Gen3 spec by 2× margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar oscillator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMK61E2-156M25SIAR | Same 156.25 MHz LVPECL output but ±50 ppm total frequency tolerance and higher current draw (208 mA vs. 208 mA typ, same spec). | Targeted at cost-sensitive industrial designs where tighter aging and temperature specs are not required. | Select LMK61E2-156M25SIAR only if ±50 ppm stability suffices and lower qualification cost is prioritized over long-term timing margin. |
| Si510-156M25-AG | 156.25 MHz LVPECL output with ±20 ppm stability, 100 fs RMS jitter, and 5 mm × 3.2 mm package - smaller footprint but non-pin-compatible. | Suitable for space-constrained client-side equipment where board redesign is acceptable. | Choose Si510-156M25-AG only when footprint reduction outweighs the need for mechanical interchangeability with 7050 packages. |
Compared with LMK61E0-156M25SIAR, LMK61E2-156M25SIAR trades ±25 ppm stability for broader qualification scope and identical pinout, while Si510-156M25-AG offers tighter initial tolerance and smaller size at the cost of PCB redesign and different thermal profile.
Availability
LMK61E0-156M25SIAR is available at Aetrix Electronics and suitable for 10G Ethernet line cards, FPGA-based test equipment, optical transport network BBUs, and PCIe Gen3 server backplanes requiring stable component supply and guaranteed long-term availability.
Supply support for LMK61E0-156M25SIAR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and high-performance timing solutions for industrial, automotive, and communications markets.
The LMK61XX family was designed to replace quartz-based oscillators in high-speed digital systems, delivering ultra-low jitter, integrated power conditioning, and factory-programmed frequencies without external configuration.
FAQ
What output format does the LMK61E0-156M25SIAR support?
The LMK61E0-156M25SIAR is factory-programmed exclusively for LVPECL output. It does not support LVDS or HCSL modes - those are implemented in other variants like LMK61A2-156M25SIAR (LVDS) or LMK61I2-100M00SIAR (HCSL). The LVPECL interface delivers 700–1200 mV differential swing with 120–200 ps edge rates, optimized for high-speed point-to-point clock distribution.
Does the LMK61E0-156M25SIAR require external configuration or programming?
No, the LMK61E0-156M25SIAR is fully factory-programmed for 156.25 MHz LVPECL operation and requires no external configuration. There are no I²C, SPI, or pin-strapping interfaces - all functionality is hard-coded during manufacturing. This eliminates boot-time configuration delays and firmware dependencies in mission-critical timing applications.
What is the maximum operating temperature for the LMK61E0-156M25SIAR?
The LMK61E0-156M25SIAR is rated for industrial temperature operation from –40°C to +85°C ambient. Its junction temperature limit is 115°C, supported by thermal design guidelines specifying ≥3 thermal vias under the exposed pad and proper PCB copper area - ensuring reliable operation in base station radios and network switches.
How does the OE pin function on the LMK61E0-156M25SIAR?
The OE (Output Enable) pin on the LMK61E0-156M25SIAR is an LVCMOS input with internal pull-up. When held high or floating, the LVPECL outputs (OUTP/OUTN) are active. When driven low, both outputs enter high-impedance state within 50 µs - enabling hardware-controlled clock gating for power management without signal contention.
Is the LMK61E0-156M25SIAR pin-compatible with standard 7050 crystal oscillators?
Yes, the LMK61E0-156M25SIAR uses a 6-pin QFM package measuring 7.0 mm × 5.0 mm - identical in footprint and pin arrangement to industry-standard 7050 XO modules. Pin 1 (OE) replaces the traditional ST/FS pin found on many XOs, but the physical layout allows direct mechanical replacement without PCB redesign.
LMK61E0-156M25SIAR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- LMK61XX
- Package/Case:
- 6-SMD Module
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Base Resonator:
- Silicon
- Type:
- XO (Standard)
- Frequency:
- 156.25 MHz
- Function:
- Enable/Disable
- Output:
- LVPECL
- Voltage - Supply:
- 3.3V
- Frequency Stability:
- ±25ppm
- Absolute Pull Range (APR):
- -
- Operating Temperature:
- -40°C ~ 85°C
- Spread Spectrum Bandwidth:
- -
- Current - Supply (Max):
- 208mA
- Ratings:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-QFM (7x5)
- Size / Dimension:
- 0.276" L x 0.197" W (7.00mm x 5.00mm)
- Height - Seated (Max):
- 0.045" (1.15mm)
LMK61E0-156M25SIAR FAQ
1.How can I place an order for LMK61E0-156M25SIAR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMK61E0-156M25SIAR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LMK61E0-156M25SIAR reliable?
The price and inventory of LMK61E0-156M25SIAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMK61E0-156M25SIAR is usually 5 days.
3.What payment methods are accepted for LMK61E0-156M25SIAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMK61E0-156M25SIAR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMK61E0-156M25SIAR?
LMK61E0-156M25SIAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMK61E0-156M25SIAR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LMK61E0-156M25SIAR?
For technical support, including LMK61E0-156M25SIAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMK61E0-156M25SIAR requirements.
6.How does Aetrix verify that LMK61E0-156M25SIAR is sourced from the original manufacturer or authorized distributors?
All LMK61E0-156M25SIAR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LMK61E0-156M25SIAR meets industry standards.
7.What is the process for return or replacement of LMK61E0-156M25SIAR?
All LMK61E0-156M25SIAR units undergo pre-shipment inspection (PSI). If there is an issue with LMK61E0-156M25SIAR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LMK61E0-156M25SIAR part is unused and in its original packaging.
Return procedure for LMK61E0-156M25SIAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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