Texas Instruments SN74ABT125DB

Overview

SN74ABT125DB from Texas Instruments is a quadruple bus buffer gate with 3-state outputs, designed for bidirectional data bus isolation in 5-V TTL-compatible systems. It delivers –32-mA high-drive IOH and 64-mA IOL, supports –40°C to 85°C operation, and features high-impedance state during power up/down for glitch-free insertion into live buses-used in backplane interface logic and memory address buffering.

For engineers reviewing the SN74ABT125DB datasheet, SN74ABT125DB pinout, SN74ABT125DB application, or SN74ABT125DB equivalent, key selection criteria include 3-state output timing (tPZH ≤ 6 ns), input clamp protection (>200 V machine model), latch-up immunity (>500 mA), and DB-package thermal resistance (158°C/W) for industrial board-level reliability.

Technical Context

This BiCMOS device implements four independent noninverting buffers, each controlled by a dedicated active-low output-enable (OE) input. Each channel transitions between low-impedance drive and high-impedance state without bus contention, with guaranteed VOL ≤ 0.55 V at IOL = 64 mA and VOH ≥ 2.0 V at IOH = –32 mA under 4.5–5.5 V supply.

Power sequencing is supported via intrinsic high-Z behavior when VCC is below 2.1 V; above that threshold, OE must be pulled high (e.g., via resistor to VCC) to ensure disable. Input transition rate is specified at ≤10 ns/V, and propagation delays range from 1 ns (min) to 6.2 ns (max) across temperature and voltage.

Key Specifications

Pinout & Package

The SN74ABT125DB uses a 14-pin Shrink Small-Outline (DB) package with 0.65-mm lead pitch and exposed pad-less construction. Pin 7 is GND, pin 14 is VCC, and all four channels are arranged symmetrically with dedicated OE, A (input), and Y (output) terminals per channel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125APW and SN74ABT244N, the SN74ABT125DB uniquely balances 5-V TTL compatibility, 4-channel density, surface-mount DB footprint, and industrial temperature range-making it optimal for space-constrained, mixed-voltage backplane interfaces where pin count and thermal performance are critical.

Availability

SN74ABT125DB is available at Aetrix Electronics and suitable for memory subsystem design, industrial backplane interconnect, and legacy bus interface applications requiring stable component supply and long-term industrial temperature support.

Supply support for SN74ABT125DB 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 founded in 1930, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The ABT logic family-including SN74ABT125DB-is engineered for high-speed, high-drive 5-V bus interfacing with enhanced noise immunity and power sequencing safety in mission-critical industrial control systems.

FAQ

What is the maximum output current rating for SN74ABT125DB?

The SN74ABT125DB supports –32 mA sourcing (IOH) and 64 mA sinking (IOL) per output under recommended operating conditions (VCC = 4.5–5.5 V). These values are tested and guaranteed across temperature, enabling direct drive of multiple TTL loads without external buffers. Exceeding these limits risks exceeding absolute maximum ratings and may degrade timing or cause thermal shutdown.

Does SN74ABT125DB support hot-plug operation?

Yes, the SN74ABT125DB enters a guaranteed high-impedance state when VCC is between 0 and 2.1 V, preventing bus contention during power-up or power-down sequences. For reliable hot-plug behavior above 2.1 V, OE must be tied to VCC via a pullup resistor-minimum value determined by the driver's current-sinking capability-to maintain disable until system control logic asserts readiness.

What is the thermal resistance (θJA) of the SN74ABT125DB package?

The SN74ABT125DB uses a 14-pin Shrink Small-Outline (DB) package with a specified junction-to-ambient thermal resistance (θJA) of 158°C/W. This value assumes standard JEDEC test conditions (single-layer board, no copper pour). Actual thermal performance improves with PCB copper area and airflow; designers should verify junction temperature using IC power dissipation and ambient conditions before final layout.

Can SN74ABT125DB operate with a 3.3-V supply?

No, the SN74ABT125DB is specified only for 4.5–5.5 V operation. Its input thresholds (VIH = 2 V, VIL = 0.8 V) and output drive strength are optimized for 5-V TTL compatibility. Applying 3.3 V violates recommended operating conditions and may result in undefined logic states, excessive ICC, or premature device failure. For 3.3-V systems, consider the SN74LVC125A series instead.

How does the SN74ABT125DB handle input transitions to prevent glitches?

The SN74ABT125DB specifies a maximum input transition rate of 10 ns/V to limit di/dt-induced noise and ensure reliable switching. Its BiCMOS EPIC-II^B process provides inherent hysteresis (Vhys = 100 mV), reducing susceptibility to slow-rising or noisy inputs. Unused inputs must be externally terminated to VCC or GND-not left floating-to avoid oscillation, increased ICC, or false output toggling.