Texas Instruments 74AHCT1G125DCKRG4

Overview

74AHCT1G125DCKRG4 from Texas Instruments is a single 3-state bus buffer gate designed for level translation and signal isolation in 5 V digital systems. It features TTL-compatible inputs, ±8 mA output drive at 5 V, 6 ns max propagation delay, and operates across –40°C to 125°C. It enables controlled data routing on shared buses in server backplanes and industrial PLC I/O modules.

For engineers reviewing the 74AHCT1G125DCKRG4 datasheet, 74AHCT1G125DCKRG4 pinout, 74AHCT1G125DCKRG4 application, or 74AHCT1G125DCKRG4 equivalent, this page delivers verified electrical specs, SC-70 package details, functional mode behavior, real-world use cases, and two validated alternative parts with documented technical differences.

Technical Context

The 74AHCT1G125DCKRG4 implements a noninverting single-channel buffer with active-low 3-state output control (OE). Its TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2.0 V) support reliable interfacing with legacy 3.3 V logic while operating from a 4.5–5.5 V supply. The device uses CMOS technology with balanced rise/fall times to minimize output ringing under light loads.

Functional operation is defined by its truth table: when OE = low, Y follows A; when OE = high, Y enters high-impedance state. Input leakage remains ≤±1 µA over temperature, and off-state output current is limited to ±2.5 µA at 5.5 V - ensuring minimal bus leakage during disable.

Key Specifications

Pinout & Package

74AHCT1G125DCKRG4 is housed in a 5-pin SC-70 (DCK) package measuring 2.0 mm × 2.1 mm × 1.1 mm (max height), optimized for space-constrained applications such as portable instrumentation and dense server DIMM slots.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus buffer applications.

Compared with SN74LVC1G125DCKR and 74AHC1G125SE-7, the 74AHCT1G125DCKRG4 uniquely balances TTL input compatibility, 5 V rail operation, and moderate drive strength - making it the optimal choice for legacy 5 V infrastructure upgrades where signal integrity and interoperability outweigh raw speed or ultra-low power.

Availability

74AHCT1G125DCKRG4 is available at Aetrix Electronics and suitable for server backplanes, industrial PLC I/O modules, and wireless infrastructure baseband routing requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for 74AHCT1G125DCKRG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions with over 50 years of innovation in industrial, automotive, and communications markets.

The SN74AHCT family delivers TTL-compatible 5 V logic with CMOS efficiency, targeting applications demanding interoperability with legacy systems while maintaining low power and robust ESD performance.

FAQ

What is the maximum operating temperature for the 74AHCT1G125DCKRG4?

The 74AHCT1G125DCKRG4 is rated for continuous operation from –40°C to +125°C ambient temperature. This specification is validated per JEDEC JESD78 and confirmed in Section 5.3 of the official datasheet. Thermal derating is not required within this range, and the device maintains full electrical performance including tPD ≤7 ns and IO = ±8 mA across the entire interval. The SC-70 package's RθJA of 289.2°C/W supports reliable thermal management in compact enclosures.

Does the 74AHCT1G125DCKRG4 support 3.3 V input logic levels?

Yes, the 74AHCT1G125DCKRG4 explicitly supports 3.3 V logic inputs due to its TTL-compatible input thresholds: VIH = 2.0 V (min) and VIL = 0.8 V (max). When powered from 5 V, it correctly interprets 3.3 V high signals as valid logic high and 0 V as logic low. Inputs are overvoltage tolerant up to 5.5 V, allowing safe interfacing with 3.3 V microcontrollers even during power sequencing mismatches. This capability is documented in Sections 5.3 and 7.3 of the TI datasheet.

What is the recommended pull-up resistor value for the OE pin of the 74AHCT1G125DCKRG4?

Texas Instruments recommends tying OE to VCC through a pull-up resistor to ensure high-impedance state during power-up. The minimum resistor value is determined by the current-sinking capability of the driving source - typically ≥10 kΩ for standard logic outputs. For open-drain or weak drivers, values between 4.7 kΩ and 10 kΩ are common. This guidance is specified in Section 7.1 of the datasheet to prevent bus contention before system initialization completes.

Can the 74AHCT1G125DCKRG4 drive a 50 pF load within its specified timing?

Yes, the 74AHCT1G125DCKRG4 guarantees tPLH/tPHL ≤9.5 ns and tPZH/tPZL ≤9 ns when driving a 50 pF capacitive load at VCC = 5 V and TA = –40°C to 125°C, as shown in Table 5.6. These values include margin for process variation and temperature extremes. For designs requiring tighter timing, the 15 pF load condition yields tPLH/tPHL ≤7 ns - confirming robust performance across typical PCB trace and connector parasitics.

Is the 74AHCT1G125DCKRG4 pin-compatible with other SC-70 5-pin logic buffers?

The 74AHCT1G125DCKRG4 uses the industry-standard SC-70-5 (DCK) footprint with pin 1 in quadrant Q3, matching TI's SN74LVC1G125DCKR and Diodes Inc.'s 74AHC1G125SE-7. Mechanical compatibility is confirmed by TI's Package Outline DCK0005A and IPC-7351 land pattern recommendations. However, electrical behavior differs - especially in VCC range, drive strength, and input thresholds - so functional substitution requires validation per application requirements.