NB2308AC4DTG

Overview

The NB2308AC4DTG is a commercial-grade, 3.3 V zero delay clock buffer manufactured by onsemi. It features an internal PLL that locks to a reference clock input and distributes high-speed signals across eight outputs organized into two banks of four. The device supports multiple frequency configurations, including 1x, 2x, and 4x multiplication depending on the feedback path selection. Key electrical specifications include a maximum operating frequency of 133.3 MHz, supply voltage range of 3.0 V to 3.6 V, and output-to-output skew less than 200 ps. It utilizes advanced 0.35 µm CMOS technology and is housed in a 16-pin TSSOP package.

Feature Summary

• Zero-delay buffering with adjustable input-to-output propagation delay via capacitive load on the FBK pin.
• Multiple configuration options allowing for 1x, 2x, or 4x frequency multiplication based on feedback source.
• Low-skew performance with output-to-output skew < 200 ps and device-to-device skew < 700 ps.
• Two independent banks of four outputs each, controllable via select inputs for three-stating or direct bypass.

Applications

• High-speed clock distribution networks requiring low jitter and skew.
• System synchronization where precise timing alignment between multiple components is critical.
• Frequency multiplication applications generating 2x or 4x clock rates from a single reference.

Procurement Notes

Verify the specific suffix 'DTG' corresponds to the TSSOP-16 package with lead-free (Pb-Free) construction and commercial temperature range (0°C to 70°C). Confirm availability status as the base NB2308A series may have end-of-life notifications; check current distributor stock levels for this specific variant before finalizing procurement plans.

Selection Notes

Select the NB2308AC4DTG when a 2x frequency multiplier is required for all outputs in a commercial temperature environment. Ensure the application load capacitance matches the datasheet requirements (15 pF for frequencies above 100 MHz) to maintain specified rise/fall times and skew parameters. Compare against NB2308AC1DTG if a 1x buffer is sufficient, or NB2308AC3DTG for 4x/2x bank-specific configurations.

Part Context

This component belongs to the NB2308A family of zero-delay buffers from onsemi. The 'C' indicates the commercial temperature grade, '4' specifies the 2x frequency multiplication configuration for all outputs, 'D' denotes the SOIC/TSSOP style package, 'T' identifies the TSSOP-16 form factor, and 'G' signifies Pb-Free compliance. Other variants in the family offer different multiplication ratios or industrial temperature ranges.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the verified source material. Designers should consult onsemi documentation for cross-reference recommendations or verify pin-compatible alternatives from other manufacturers such as Cypress Semiconductor (e.g., CY2305 series) after confirming electrical parameter compatibility.

FAQ

How is the zero-delay characteristic achieved?

Zero input-to-output delay is achieved by connecting the feedback pin (FBK) to one of the outputs. The relative loading capacitance between the FBK pin and the other outputs adjusts the internal delay to match the input-to-output propagation time.

What is the function of the S1 and S2 select inputs?

The S1 and S2 inputs control the operation mode. Setting them to logic high enables the PLL mode. Setting both to logic low three-states all outputs. Setting S1 high and S2 low bypasses the PLL, applying the reference clock directly to the outputs.

Can Bank B be independently controlled?

Yes, Bank B can be three-stated while Bank A remains active, or vice versa, using the select inputs. This allows for flexible clock gating and system testing without affecting the entire device.