MC74VHC1GT126D1G

Overview

The MC74VHC1GT126D1G is a single-gate non-inverting 3-state buffer from the VHC logic family, manufactured by onsemi. It operates within a supply voltage range of 2.0 V to 5.5 V and features TTL-level input thresholds. The device provides high noise immunity through a buffered three-stage internal circuit and includes over-voltage tolerant inputs and outputs up to 5.5 V, regardless of the supply voltage. It supports partial power down protection via IOFF and offers source/sink capabilities of 8 mA at 3.0 V. The component is available in compact packages including SC-74A (DBVT suffix) and SC-88A.

Feature Summary

• Single non-inverting 3-state buffer with TTL-level input thresholds for interfacing 5 V circuits to 3 V circuits
• Over-voltage tolerant inputs and outputs up to 5.5 V, providing protection against supply/input/output voltage mismatches
• IOFF feature supports partial power down protection to prevent excessive current draw when VCC = 0 V
• High noise immunity and stable output provided by a buffered three-stage internal circuit structure

Applications

• Interfacing 5 V circuits to 3 V circuits
• Battery backup systems requiring protection against voltage mismatch
• Hot insertion applications involving supply voltage transitions
• General purpose buffering in portable and battery-operated devices

Procurement Notes

Verify the specific package suffix (e.g., DBVT for SC-74A or DFT for SC-88A) matches the required footprint, as the base part number covers multiple physical configurations. Confirm that the GT designation aligns with the need for TTL-level input thresholds rather than CMOS levels found in the G variant. Ensure the -Q suffix is not required if automotive qualification or unique site control changes are necessary for the application.

Selection Notes

Select this component when a single-channel non-inverting buffer with 3-state output control is needed in a minimal footprint. The TTL input threshold makes it suitable for driving from 5 V logic sources into lower voltage domains. Consider the SC-74A or SC-88A packages for space-constrained designs. Verify that the 8 mA drive capability meets the load requirements and that the 2.0 V to 5.5 V operating range covers the system's supply voltage variations.

Part Context

This device belongs to the MC74VHC1G/1GT series of single-gate buffers. It shares functional similarities with the MC74VHC1GT125 but differs in input threshold characteristics; the GT variant uses TTL thresholds while other variants may use CMOS thresholds. It is part of onsemi's VHC (Very High Speed CMOS) line, designed for low power consumption and high-speed operation in compact surface-mount packages.

Replacement Considerations

MC74VHC1GT125DBVT1G: Similar 3-state buffer but with CMOS-level input thresholds instead of TTL.

FAQ

What is the difference between MC74VHC1G126 and MC74VHC1GT126?

The MC74VHC1G126 has CMOS-level input thresholds, while the MC74VHC1GT126 has TTL-level input thresholds, allowing it to interface directly with 5 V logic signals.

How does the IOFF feature work?

The IOFF feature ensures that when the supply voltage (VCC) is zero, the inputs and outputs are disabled to prevent excessive current flow from external voltage sources, supporting partial power down modes.