Texas Instruments SN74CBT3125DGVR

Overview

SN74CBT3125DGVR from Texas Instruments is a quadruple FET bus switch IC with independent 5-Ω analog switches, TTL-compatible control inputs, and 4.0–5.5 V supply operation. It enables bidirectional signal routing in data buses, memory expansion interfaces, and level-shifting applications where low on-resistance and fast switching are critical.

For engineers reviewing the SN74CBT3125DGVR datasheet, SN74CBT3125DGVR pinout, SN74CBT3125DGVR application, or SN74CBT3125DGVR equivalent, key selection considerations include on-state resistance (5–7 Ω), propagation delay (0.25–0.35 ns), enable/disable timing (1.6–6 ns), thermal performance (θ_JA = 127°C/W), and TVSOP-14 package compatibility with high-density PCB layouts.

Technical Context

The SN74CBT3125DGVR implements four independent single-pole single-throw (SPST) FET switches, each controlled by a dedicated output-enable (OE) input. Each switch connects its A and B ports when OE is low (L), and presents high-impedance isolation when OE is high (H).

It operates as a passive analog switch - not a logic gate - with rail-to-rail signal handling, no internal level translation, and no DC bias requirements on switched signals. The device uses NMOS pass transistors with integrated charge pumps to ensure full turn-on across the 4–5.5 V V_CC range.

Key Specifications

Pinout & Package

SN74CBT3125DGVR is housed in a 14-pin Thin Very Small Outline Package (TVSOP), measuring 4.9 mm × 3.9 mm × 1.2 mm (max height), with 0.65 mm lead pitch and gull-wing leads. It features exposed pad-less construction and JEDEC MO-194 compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3125DGVR, SN74CBTD3384DGVR offers double the channel count but sacrifices 5-V compatibility and adds 2 Ω r_on, while 74LVC1G3157GW trades integration for miniaturization and wider voltage flexibility - neither provides identical 4-channel + 5-V + 5-Ω performance in TVSOP-14.

Availability

SN74CBT3125DGVR is available at Aetrix Electronics and suitable for memory expansion interfaces, hot-swappable peripheral buses, level-shifted data multiplexing, and test access port isolation requiring stable component supply across industrial temperature ranges (−40°C to 85°C).

Supply support for SN74CBT3125DGVR 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 digital signal technologies, with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74CBT3125DGVR belongs to TI's CBT (CrossBar Technology) family of high-speed FET bus switches, engineered for low-latency, low-distortion signal routing in 5-V digital systems where timing predictability and bus integrity are critical.

FAQ

What is the maximum continuous current per channel for SN74CBT3125DGVR?

The SN74CBT3125DGVR supports up to 128 mA continuous channel current per switch, as specified in its absolute maximum ratings. This rating applies under steady-state conditions with proper PCB thermal design; actual usable current depends on ambient temperature, trace width, and copper area - for example, at 85°C ambient and 127°C/W θ_JA, sustained 64 mA operation remains within safe junction limits. The SN74CBT3125DGVR datasheet confirms this value on page 2 under "Absolute Maximum Ratings".

Does SN74CBT3125DGVR require external pull-up resistors on its OE pins?

Yes - to ensure high-impedance state during power-up or power-down, each OE pin of the SN74CBT3125DGVR must be tied to V_CC through an external pull-up resistor. The minimum resistance value depends on the current-sinking capability of the driving source; TI recommends verifying driver strength against the 15 mA max I_OH spec. This requirement is explicitly stated in the "Description" section of the SN74CBT3125DGVR datasheet (page 1).

Can SN74CBT3125DGVR be used for analog signal switching, such as audio or sensor signals?

Yes - the SN74CBT3125DGVR is a bidirectional analog switch with rail-to-rail signal handling and no internal DC bias, making it suitable for low-frequency analog signals like audio, thermistor readings, or PWM control lines. Its 5 Ω r_on introduces negligible attenuation below 10 MHz, and 4 pF off-capacitance limits crosstalk. However, it lacks built-in ESD protection beyond HBM, so external clamping may be needed for exposed analog inputs. This analog capability is confirmed by the "Function Table" and "Electrical Characteristics" sections of the SN74CBT3125DGVR datasheet.

What is the thermal resistance (θ_JA) of SN74CBT3125DGVR, and how does it affect layout?

The SN74CBT3125DGVR has a junction-to-ambient thermal resistance (θ_JA) of 127°C/W, as measured per JESD 51-7. This relatively high value means the TVSOP-14 package relies heavily on PCB copper area for heat dissipation - designers should use ≥2 cm² of 2-oz copper connected to GND and V_CC pins via multiple thermal vias. Without adequate copper, even modest 100 mW total power dissipation can exceed 125°C junction temperature. This specification appears in the "Absolute Maximum Ratings" table on page 2 of the SN74CBT3125DGVR datasheet.

Is SN74CBT3125DGVR pin-compatible with other packages in the same family, such as SN74CBT3125DBR?

Yes - the SN74CBT3125DGVR shares identical pinout with SN74CBT3125DBR (SSOP-14), SN74CBT3125DR (SOIC-14), and SN74CBT3125PWR (TSSOP-14), as confirmed by the "Standard '125-Type Pinout" diagram on page 1 of the SN74CBT3125DGVR datasheet. All use the same 14-pin arrangement: OE/A/B assignments and NC locations match exactly. However, physical dimensions and solder profiles differ - TVSOP requires tighter stencil apertures and reflow profiling than SOIC or SSOP.