Texas Instruments SN74CBTD1G125DBVT

Overview

SN74CBTD1G125 from Texas Instruments is a single-channel FET bus switch with integrated level shifting, designed for bidirectional signal routing between 5-V and 3.3-V logic domains. It features 5-Ω on-state resistance, <0.25 ns propagation delay, TTL-compatible control inputs, and operates from 4.5 V to 5.5 V supply. It is used in voltage-level translation for data buses in embedded controllers and interface bridges.

For engineers reviewing the SN74CBTD1G125 datasheet, SN74CBTD1G125 pinout, SN74CBTD1G125 application, or SN74CBTD1G125 equivalent, key selection criteria include on-resistance stability across temperature, OE-controlled isolation timing (ten ≤ 5.9 ns, tdis ≤ 4.7 ns), ESD robustness (2000-V HBM), latch-up immunity (>100 mA), and SOT-23 (DBV) package compatibility with high-density PCB layouts.

Technical Context

The SN74CBTD1G125 implements a single NMOS transmission gate with an integrated diode to VCC for passive level shifting-enabling 5-V input signals to produce 3.3-V compatible outputs without external biasing. Its OE pin controls conduction state with active-low logic: low enables A↔B continuity; high disconnects both ports.

It operates strictly within 4.5–5.5 V VCC, supports ±128 mA continuous channel current, and maintains sub-7 Ω on-resistance at VI = 2.4 V and II = 15 mA. Input clamp current rating (–50 mA) and thermal impedance (206 °C/W, DBV) are specified for reliability under transient stress and sustained load conditions.

Key Specifications

Pinout & Package

SOT-23 (DBV) 5-pin package: 1.45 mm max height, 2.9 mm × 1.6 mm footprint, gull-wing leads, RoHS-compliant NIPDAU/SN finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTD1G125, SN74LVC1G3157DBVR offers wider supply flexibility but lacks native 5-V-to-3.3-V translation, while 74CBTLV1G125GW,125 provides lower Ron but requires strict 3.3-V operation-neither matches SN74CBTD1G125's specific combination of 5-V-tolerant inputs, integrated diode-based level shifting, and 4.5–5.5 V operation.

Availability

SN74CBTD1G125DBVT is available at Aetrix Electronics and suitable for PCIe Gen1 bridging, industrial serial bus isolation, and USB 1.1 data line buffering requiring stable component supply across extended temperature ranges and long-lifecycle programs.

Supply support for SN74CBTD1G125DBVT 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and industrial-grade qualification.

The SN74CBTD1G125 belongs to TI's 74CBT logic family, engineered for high-speed, low-distortion bus switching in mixed-voltage systems where level translation and fast enable/disable control are critical.

FAQ

What is the maximum continuous current rating for SN74CBTD1G125DBVT?

The SN74CBTD1G125DBVT supports a continuous channel current of 128 mA, verified per absolute maximum ratings in the official datasheet. This rating applies across the full operating temperature range (–40°C to +85°C) and ensures reliable conduction without thermal runaway when used within recommended VCC (4.5–5.5 V) and load conditions. Exceeding this current may degrade on-resistance or trigger latch-up.

Does SN74CBTD1G125DBVT require external pull-up resistors for level shifting?

No, SN74CBTD1G125DBVT does not require external pull-up resistors for 5-V-to-3.3-V level shifting. It integrates a diode to VCC on-chip that passively clamps and shifts input signals-enabling direct connection of 5-V sources to port A while delivering 3.3-V compatible outputs at port B. External components are unnecessary unless driving capacitive loads exceeding 50 pF.

Can SN74CBTD1G125DBVT operate with a 3.3-V supply voltage?

No, SN74CBTD1G125DBVT cannot operate with a 3.3-V supply. Its recommended VCC range is strictly 4.5 V to 5.5 V, and absolute maximum ratings specify –0.5 V to 7 V. Supplying 3.3 V will result in insufficient gate drive for the internal FET, causing high on-resistance (>50 Ω), unreliable switching, and potential functional failure. Use SN74LVC1G3157DBVR instead for 3.3-V-only operation.

What is the thermal resistance (θJA) of SN74CBTD1G125DBVT in its SOT-23 (DBV) package?

The junction-to-ambient thermal resistance (θJA) of SN74CBTD1G125DBVT in the SOT-23 (DBV) package is 206 °C/W, as specified in the Absolute Maximum Ratings table. This value assumes standard JEDEC test board conditions (2-layer board, 1-in² copper pad). Actual thermal performance improves with enhanced PCB copper area or thermal vias, but derating is required above 70°C ambient for sustained 128 mA operation.

Is SN74CBTD1G125DBVT pin-compatible with SN74CBTD1G125DCKT?

Yes, SN74CBTD1G125DBVT and SN74CBTD1G125DCKT share identical pin functions (OE, GND, A, B, VCC) and logic behavior, but they differ in package: DBVT uses SOT-23 (DBV), while DCKT uses SC-70 (DCK). Both are 5-pin, single-switch devices with identical electrical specs. However, their land patterns, thermal impedance (206 vs. 252 °C/W), and mechanical dimensions are not interchangeable without PCB redesign.