CB-8OUT-LVDS
High-performance 8-output LVDS clock buffer with additive jitter of 0.1ps for high-speed clock distribution.
Product Overview
Description
This clock buffer accepts a differential LVDS or LVPECL input and provides eight identical LVDS outputs with ultra-low additive jitter of only 0.1ps RMS.
The device is ideal for high-speed ADC/DAC clocking, FPGA clock distribution, and telecommunications equipment where maintaining signal integrity is critical.
With support for frequencies up to 1.5GHz and wide operating temperature range, this buffer meets the demanding requirements of high-performance systems.
Product Series
CB
Primary Application
ADC/DAC clocking
Key Features
- 8 LVDS outputs
- 0.1ps additive jitter
- 1.5GHz max frequency
- 2.5V/3.3V operation
Specifications
| Input Frequency | Up to 1.5GHz |
|---|---|
| Input Type | LVDS or LVPECL |
| Output Type | 8 x LVDS |
| Output Impedance | 100 ohms differential |
| Additive Jitter | 0.1ps RMS typical |
| Supply Voltage | 2.5V or 3.3V |
| Operating Current | 120mA typical |
| Operating Temperature | -40C to +85C |
| Package | QFN 5.0 x 5.0 x 0.9mm |
Applications
ADC/DAC clocking
Data acquisition and conversion
FPGA clock distribution
Electronic system design
Telecom equipment
Electronic system design
High-speed computing
Electronic system design
Test equipment
Electronic system design
FAE Expert Insights
"The CB-8OUT-LVDS is an excellent clock buffer for high-performance applications. I have used this buffer in multiple high-speed ADC and FPGA designs where low jitter is critical. The 0.1ps additive jitter is among the best in the industry and has minimal impact on the source clock quality. The LVDS outputs provide excellent signal integrity even over long PCB traces. I particularly appreciate the flexibility of 2.5V or 3.3V operation, allowing use in various system designs. The 8 outputs can drive multiple ADCs or FPGA banks from a single clock source, simplifying system architecture. For high-speed data converter applications, this buffer ensures sampling clock quality is maintained throughout the system."
Ultra-low jitter clock buffer ideal for high-speed ADC and FPGA applications
— Alex Chen, BeiLuo
Frequently Asked Questions
What is additive jitter and why is it important?
Additive jitter is the additional jitter introduced by the clock buffer: Definition - jitter added to the input clock signal as it passes through the buffer. Measurement - compare output jitter to input jitter, the difference is additive jitter. Importance - cumulative jitter degrades system timing margin. This buffer - 0.1ps additive jitter is extremely low. Impact - minimal degradation of clock quality. Typical values - standard buffers add 0.3-1.0ps, this buffer adds only 0.1ps. For high-speed systems: ADC/DAC sampling clocks - low additive jitter maintains SNR. High-speed serial - low jitter ensures bit error rate specs. FPGA clocks - low jitter preserves timing margin. This buffer's 0.1ps performance is suitable for the most demanding applications.
Choose this buffer for applications where preserving clock quality is critical.
How do I terminate LVDS outputs properly?
LVDS output termination requirements: Termination resistor - 100 ohms differential across the output pair. Placement - place resistor at the receiver end of the trace. Trace routing - route as 100 ohm differential pair. Trace length - keep traces as short as possible, <6 inches recommended. Impedance control - maintain 100 ohm differential impedance. Stub length - minimize stubs at the receiver. This buffer has integrated current sources, so only the 100 ohm termination resistor is needed at the receiver. No additional resistors at the buffer output. For multiple loads: Point-to-point - best signal integrity, one receiver per output. Daisy chain - possible for closely spaced receivers. Star routing - avoid, causes reflections. Follow these guidelines for best signal integrity.
Use 100 ohm differential termination at receiver. Contact us for layout recommendations.
Can I use this buffer with single-ended clock inputs?
This buffer requires differential input: Input type - LVDS or LVPECL differential only. Single-ended - not directly supported. Conversion options: Single-ended to differential converter IC. Transformer coupling - for high frequencies. Resistive network - converts CMOS to LVDS (not recommended for precision). Recommended approach: Use a differential oscillator as the clock source. Most precision oscillators offer LVDS or LVPECL outputs. This ensures best signal integrity from source to destination. If you must use single-ended: Consider CB-CMOS-8OUT for CMOS inputs. Add external single-ended to differential converter. Contact us for application guidance. For best performance, use differential signaling throughout the clock path.
Use differential clock source for best performance. Contact us for single-ended alternatives.
What is the maximum fan-out for each output?
Fan-out recommendations for LVDS outputs: Standard load - one LVDS receiver per output (point-to-point). Multiple loads - daisy chain up to 2-3 closely spaced receivers. Maximum - depends on trace length and receiver input capacitance. Loading effects: Each receiver adds ~3pF input capacitance. Multiple receivers degrade signal edge rates. Reflections occur with improper termination. Best practices: Point-to-point - one receiver per output for best signal integrity. Use multiple outputs - buffer has 8 outputs for distribution. Clock tree - use multiple buffers for large fan-out. Simulation - simulate clock distribution for critical designs. This buffer is designed to drive standard LVDS loads. For driving many loads, consider using multiple buffers in a clock tree architecture.
Use point-to-point for best signal integrity. Contact us for large fan-out solutions.
How do I power the buffer for lowest jitter?
Power supply recommendations for lowest jitter: Voltage selection - 2.5V or 3.3V, choose based on system. Lower voltage - 2.5V may have slightly lower noise. Decoupling - 0.1uF ceramic per power pin, close to device. Bulk capacitance - 1-10uF near the device. Power supply noise - use clean, low-noise supply. LDO regulator - recommended for clock buffer power. Avoid: Switching noise - keep away from switching power supplies. Shared supplies - avoid sharing with noisy digital circuits. Long traces - keep power traces short and wide. Layout tips: Solid ground plane under buffer. Multiple vias for ground connections. Keep decoupling caps within 2mm. Follow evaluation board layout. Good power supply design is essential for achieving the specified 0.1ps additive jitter performance.
Use clean LDO power with adequate decoupling. Contact us for power design recommendations.