Texas Instruments SN74LVC125ADR

Overview

SN74LVC125ADR from Texas Instruments is a quadruple 3-state bus buffer gate operating from 1.65V to 3.6V, featuring independent output-enable (OE) inputs per channel, 4.8ns max propagation delay at 3.3V, and 5.5V-tolerant inputs - enabling level translation in mixed-voltage 3.3V/5V systems such as telecom baseband units and optical networking interfaces.

For engineers reviewing the SN74LVC125ADR datasheet, SN74LVC125ADR pinout, SN74LVC125ADR application, or SN74LVC125ADR equivalent, this device supports high-speed bidirectional bus isolation, low-power logic interfacing, and robust ESD protection (±2000V HBM), with design-critical parameters including tpd, VOH/VOL drive strength, and thermal resistance (RθJA = 127.8°C/W in SOIC-14).

Technical Context

The SN74LVC125ADR implements four independent CMOS buffer channels, each with noninverting logic and active-low 3-state control. Each OE input directly gates its corresponding A→Y path, allowing per-channel bus arbitration without shared enable logic.

Its 5.5V-tolerant inputs and rail-to-rail output swing (VOH ≥ VCC–0.2V, VOL ≤ 0.3V at 3.3V) support interoperability between legacy 5V peripherals and modern 3.3V controllers, while latch-up immunity (>250mA per JESD17) ensures reliability in noisy telecom environments.

Key Specifications

Pinout & Package

SN74LVC125ADR uses the SOIC-14 (D) package: 8.6mm × 6.0mm body, 14-pin gull-wing leadframe, RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C peak reflow), and -40°C to +125°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125ADR, the SSOP and TSSOP alternatives offer smaller footprints but require stricter thermal management due to higher RθJA values - making the SOIC-14 version optimal for thermally demanding telecom base station applications where layout area is less critical than reliability.

Availability

SN74LVC125ADR is available at Aetrix Electronics and suitable for telecom baseband units, optical networking interfaces, and wireless infrastructure RRUs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVC125ADR 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 connectivity solutions for industrial, automotive, and communications markets.

The SN74LVC125ADR belongs to TI's LVC logic family - designed specifically for low-voltage, high-speed, mixed-signal interfacing in telecom infrastructure, where voltage translation, noise immunity, and thermal robustness are critical.

FAQ

What is the maximum clock frequency supported by SN74LVC125ADR?

The SN74LVC125ADR does not operate as a clocked device but as a combinational buffer. Its 4.8ns max propagation delay at 3.3V supports data toggle rates exceeding 200MHz on well-terminated lines. For reliable operation, ensure setup/hold times are met relative to system timing margins - the SN74LVC125ADR itself imposes no internal clock limit.

Can SN74LVC125ADR safely interface a 5V microcontroller with a 3.3V FPGA?

Yes. The SN74LVC125ADR accepts input voltages up to 5.5V regardless of VCC (1.65V–3.6V), making it ideal for translating 5V logic levels to 3.3V domains. When powered at 3.3V, its outputs swing rail-to-rail, ensuring compatible VOH/VOL thresholds for the FPGA - no external resistors or translators needed.

Does SN74LVC125ADR require external pull-up resistors on OE pins?

Yes - to guarantee high-impedance state during power-up/power-down, each OE pin should be tied to VCC via a pull-up resistor. The minimum value depends on the driver's current-sourcing capability; TI recommends starting with 10kΩ and verifying behavior under worst-case VCC ramp rates in your system.

What is the thermal performance of SN74LVC125ADR in SOIC-14 package?

The SN74LVC125ADR in SOIC-14 has a junction-to-ambient thermal resistance (RθJA) of 127.8°C/W. Above 70°C ambient, power dissipation must be linearly derated at 8mW/°C. At 100mW total dissipation, junction temperature rises ~12.8°C above ambient - confirming suitability for sealed telecom enclosures up to 85°C ambient.

Is SN74LVC125ADR pin-compatible with older 74LS125 or 74HC125 devices?

No. While functionally similar as quad 3-state buffers, the SN74LVC125ADR uses a different pinout than 74LS125 (which has shared OE) and differs electrically from 74HC125 (higher VCC max, 5.5V-tolerant inputs). Direct replacement requires PCB redesign - always verify pin mapping and voltage compatibility before substitution.