NB2308AI2DTR2G

Overview

The NB2308AI2DTR2G is a 3.3 V zero delay clock buffer from the NB2308A family, manufactured by onsemi. It features an internal PLL that locks to a reference clock input and provides eight low-skew outputs organized into two banks of four. The device supports configurable frequency multiplication (2X or 4X) based on feedback selection. Key electrical parameters 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 operates within an industrial temperature range of -40°C to 85°C and is housed in a 16-pin TSSOP package.

Feature Summary

• Zero Delay Buffer with adjustable input-to-output propagation delay via capacitive load on FBK pin
• Configurable frequency multiplication: 2X or 4X depending on feedback source selection
• Low skew performance: Output-to-output skew < 200 ps; Device-to-device skew < 700 ps
• Two banks of four outputs with three-state control via S1/S2 select inputs

Applications

• High-speed clock distribution in multi-chip modules
• System synchronization where precise phase alignment between multiple devices is required
• Clock buffering for processors and memory interfaces requiring low jitter

Procurement Notes

Verify the 'I' suffix indicates Industrial temperature grade (-40°C to 85°C). Confirm the 'DT' suffix corresponds to the TSSOP-16 package and 'R2' denotes Tape & Reel packaging with 2500 units per reel. Ensure compatibility with 3.3 V logic levels and check for RoHS compliance if lead-free status is required.

Selection Notes

Select this part when a 2X or 4X frequency multiplier is needed alongside clock buffering. Choose NB2308AI2 over AI1 if frequency doubling/tripling is required. Verify that the application can accommodate the specific feedback configuration (Bank A or B) to achieve the desired output frequencies. Ensure load capacitance requirements (15 pF for >100 MHz) are met to maintain specified timing parameters.

Part Context

This component belongs to the NB2308A series of 3.3 V zero delay buffers. Variants differ by frequency multiplication capability (x1, x2, x3, x4, x5H), drive strength (standard vs. H), and package type (SOIC-16 vs. TSSOP-16). The AI2 variant specifically offers 2X/4X multiplication options with industrial temperature rating.

Replacement Considerations

NB2308AC2DTR2G (Commercial temp version)

FAQ

How is zero input-to-output delay achieved?

Zero delay is achieved by ensuring the capacitive load on the FBK pin matches the load on the output pins driving it. Adjusting the difference in loading between the FBK pin and CLKA/CLKB pins allows fine-tuning of the propagation delay.

What determines the output frequency configuration?

The output frequency configuration (Reference, 2X, or 4X) is determined by which output pin drives the FBK feedback pin. For the NB2308Ax2/x3 variants, connecting Bank A or Bank B outputs to FBK selects different multiplication factors for the banks.

Can unused outputs be disabled?

Yes, unused outputs can be placed in a three-stated state using the S1 and S2 select inputs. For example, setting S2=0 and S1=0 places all outputs in three-state mode and shuts down the PLL.