NB2308AI2HDG

Overview

The NB2308AI2HDG is a 3.3 V zero delay clock buffer manufactured by onsemi, designed for high-speed clock distribution. It features an internal phase-locked loop (PLL) that locks to an input clock on the REF pin, with feedback driven from one of the eight outputs to the FBK pin. The device provides two banks of four single-ended LVCMOS outputs each. Key electrical parameters include an operating supply voltage range of 3.0 V to 3.6 V and an input frequency range of 15 MHz to 133 MHz. It guarantees an output-to-output skew of less than 200 ps within the same bank and less than 400 ps between Bank A and Bank B.

Feature Summary

• Configurable frequency multiplication: Provides 2X reference frequency on Bank A and Reference frequency on Bank B when feedback is sourced from Bank B.
• Low skew performance: Guarantees output-to-output skew under 200 ps within the same bank and under 400 ps between banks.
• Flexible control: Includes two select inputs (S1, S2) to enable three-stating of output banks or bypass mode for direct clock application.
• Zero delay adjustment: Input-to-output propagation delay is adjustable via capacitive load differences on the FBK pin relative to other outputs.

Applications

• High-speed clock distribution in computing systems
• Clock buffering for memory interfaces
• System synchronization requiring low jitter and skew

Procurement Notes

Verify the ordering suffix 'HDG' confirms the SOIC-16 package and industrial/commercial temperature range (-40°C to +85°C). Confirm RoHS compliance and lead-free status as specified in the datasheet. Check current availability status as product lifecycles may change.

Selection Notes

Select this part when a 2X clock multiplier is required for one output bank while maintaining reference frequency on the other. Ensure the feedback path connects from a Bank B output to the FBK pin to achieve the specified 2X/Reference configuration. Verify load capacitance requirements (15 pF for >100 MHz, 30 pF for <100 MHz) to maintain timing specifications.

Part Context

This component belongs to the NB2308A family of 3.3 V zero delay buffers. It shares the same 16-pin package and basic PLL architecture with variants like NB2308AI1, AI3, and AI4, which offer different frequency multiplication ratios such as 1X, 4X, or dual 2X configurations across both banks.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Other members of the NB2308A family (e.g., NB2308AI1, NB2308AI3) share the same package but differ in frequency configuration and should be evaluated based on specific circuit requirements.

FAQ

How is the 2X frequency generated on Bank A?

The NB2308AI2 generates a 2X frequency on Bank A when the feedback pin (FBK) is driven by an output from Bank B. In this configuration, Bank A outputs operate at twice the reference frequency while Bank B outputs operate at the reference frequency.

What is the maximum output-to-output skew between banks?

For the NB2308AI2, the output skew between Bank A and Bank B is guaranteed to be less than 400 ps when all outputs are equally loaded.

Can the outputs be disabled?

Yes, the two select inputs (S1 and S2) allow individual control of the output banks. Setting the appropriate logic levels can place either Bank A, Bank B, or both into a three-state condition.