Texas Instruments SN74ALVC125PWRE4

Overview

SN74ALVC125PWRE4 from Texas Instruments is a quadruple bus buffer gate with 3-state outputs, designed for 1.65-V to 3.6-V VCC operation. It provides four independent non-inverting buffers with active-low output-enable control, ±24-mA drive strength at 3.3 V, 2.8-ns max propagation delay, and operates across –40°C to 85°C. It serves as a level-translating signal isolator in digital interface backplanes and memory address/data buses.

For engineers reviewing the SN74ALVC125PWRE4 datasheet, SN74ALVC125PWRE4 pinout, SN74ALVC125PWRE4 application, or SN74ALVC125PWRE4 equivalent, key selection criteria include 3-state output timing (ten/tdis), supply voltage range compatibility (1.65–3.6 V), output drive capability (±24 mA @ 3 V), thermal impedance (θJA = 113°C/W), and TSSOP-14 package footprint constraints.

Technical Context

This device implements four independent CMOS buffer stages, each with a dedicated active-low output-enable (OE) input controlling high-impedance state entry. Output logic follows positive-logic truth table: when OE = L, Y = A; when OE = H, Y = Z (high-Z). No internal latch-up protection circuitry is integrated beyond JESD17-compliant robustness (>250 mA).

Input thresholds scale with VCC (VIH = 0.65×VCC min at 1.65 V; 2.0 V min at 3.6 V); output VOH/VOL specs are load-dependent (e.g., VOH ≥ 2.0 V at IOH = –24 mA, VCC = 3.0 V). Power dissipation per gate is 19 pF typical at 3.3 V, 10 MHz, with ICC ≤ 10 µA in static operation.

Key Specifications

Pinout & Package

TSSOP-14 (PW) package: 4.4 mm × 5.0 mm body, 0.65 mm pitch, 1.2 mm max height, exposed pad not present, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125APWR and 74AVC125TTR, SN74ALVC125PWRE4 uniquely delivers 3.6-V absolute maximum supply rating, ±24-mA drive at 3 V, and guaranteed 2.8-ns tpd - making it optimal for mixed-voltage industrial backplanes requiring robustness and timing margin.

Availability

SN74ALVC125PWRE4 is available at Aetrix Electronics and suitable for memory subsystems, FPGA I/O expansion, hot-pluggable backplanes, and low-power sensor hub designs requiring stable component supply across extended temperature ranges.

Supply support for SN74ALVC125PWRE4 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 decades of expertise in high-reliability logic families.

The ALVC (Advanced Low-Voltage CMOS) product line targets high-speed, low-voltage digital interface applications requiring wide VCC range, strong drive, and industrial temperature operation - specifically optimized for voltage translation and bus isolation in mixed-supply systems.

FAQ

What is the recommended power-up sequence for SN74ALVC125PWRE4 to avoid bus contention?

TI recommends tying all OE pins to VCC through a pullup resistor (value determined by driver sink capability) to ensure outputs remain in high-impedance state during power ramp. This prevents unintended signal assertion before system initialization. The SN74ALVC125PWRE4 does not require strict VCC sequencing relative to other rails, as its 1.65–3.6 V range accommodates staggered supply ramps common in multi-rail systems.

Can SN74ALVC125PWRE4 safely interface between 1.8-V and 3.3-V logic domains without external level-shifting components?

Yes. SN74ALVC125PWRE4 supports 1.65–3.6 V VCC and has input thresholds that scale with VCC (VIH ≥ 0.65×VCC). When powered at 3.3 V, it reliably accepts 1.8-V inputs as valid logic high; when powered at 1.8 V, its outputs swing to ~1.6 V, sufficient to drive 1.8-V CMOS inputs. Thus, SN74ALVC125PWRE4 functions as a bidirectional level translator in many configurations without added components.

What is the maximum capacitive load SN74ALVC125PWRE4 can drive while maintaining 2.8-ns propagation delay?

The 2.8-ns max tpd is specified at CL = 50 pF (per TI SCES110H, VCC = 3.3 V, TA = 25°C). Driving loads >50 pF increases propagation delay nonlinearly - e.g., at 100 pF, tpd degrades to ~4.3 ns. For SN74ALVC125PWRE4, maintain total net capacitance ≤50 pF (including trace, via, and receiver input) to guarantee datasheet timing performance in high-speed applications.

Does SN74ALVC125PWRE4 require external current-limiting resistors on its outputs when driving LEDs or other DC loads?

No - SN74ALVC125PWRE4 is not intended for direct LED driving. Its outputs are designed for logic-level signaling, not sustained DC current. While it can source/sink ±24 mA peak, continuous DC loading risks exceeding SOA limits and accelerating wear-out. For LED indicators, use a series resistor calculated for target current and forward voltage; for higher-power loads, add a discrete MOSFET or driver IC. SN74ALVC125PWRE4 should only drive logic inputs or terminated transmission lines.

How does the thermal performance of SN74ALVC125PWRE4 compare to SOIC-packaged variants like SN74ALVC125DR?

SN74ALVC125PWRE4 (TSSOP-14) has θJA = 113°C/W, versus 86°C/W for SN74ALVC125D (SOIC-14). This means the TSSOP version heats up ~31% more per watt under identical board conditions. To maintain reliability at full drive (e.g., 4×24 mA), reduce ambient temperature, improve airflow, or limit simultaneous active buffers. Derate power linearly above 65°C ambient; SN74ALVC125PWRE4 remains fully specified to 85°C only when PCB copper area and layout follow TI's TSSOP thermal guidelines.