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Home > Products > Integrated Circuits (ICs) > Logic > Signal Switches, Multiplexers, Decoders

Texas Instruments SN74CBT3125RGYR

Name: SN74CBT3125RGYR
Brand: Texas Instruments
SKU: SN74CBT3125RGYR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74CBT3125RGYR

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: 14-VFQFN Exposed Pad

Datasheet:: SN74CBT3125RGYR.pdf

Description:: IC BUS SWITCH 1 X 1:1 14VQFN

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Product details

Overview

SN74CBT3125RGYR from Texas Instruments is a quadruple FET bus switch IC with independent 5-Ω on-state resistance switches, TTL-compatible control inputs, and 4.0–5.5 V supply operation. It enables bidirectional signal routing in high-speed digital systems such as memory address/data buses and FPGA I/O expansion.

For engineers reviewing the SN74CBT3125RGYR datasheet, SN74CBT3125RGYR pinout, SN74CBT3125RGYR application, or SN74CBT3125RGYR equivalent, key selection criteria include on-resistance consistency across channels, propagation delay under 0.35 ns at 4 V, thermal performance (θ_JA = 47°C/W), and QFN-14 package compatibility with space-constrained PCB layouts.

Technical Context

This device implements four independent single-pole single-throw (SPST) analog switches using NMOS FETs, each controlled by a dedicated output-enable (OE) input. Each channel connects A and B ports bidirectionally when OE is low, and presents high-impedance isolation when OE is high.

It operates without level-shifting-supporting 3.3 V/5 V mixed-signal interfacing-and features rail-to-rail signal handling (−0.5 V to 7 V input range), low charge injection (<1 pC typical), and fast enable/disable timing (t_en ≤ 6 ns, t_dis ≤ 5.1 ns at V_CC = 4 V).

Key Specifications

Parameter	Value and Actual Design Meaning
On-state resistance (r_on)	5 Ω typical at V_CC = 4 V, 15 mA - ensures minimal voltage drop and signal distortion in 50-Ω impedance-matched paths.
Propagation delay (t_pd)	0.35 ns max at V_CC = 4 V - supports >1 GHz data rates in high-speed parallel bus applications.
Supply voltage range	4.0–5.5 V - compatible with standard 5 V logic rails and tolerant of 4 V industrial supply margins.
Input voltage range (VI)	−0.5 V to 7 V - allows safe interfacing with overvoltage-tolerant peripherals and hot-swap scenarios.
Thermal resistance (θ_JA)	47°C/W for RGY package - enables higher continuous current (128 mA per channel) without external heatsinking in compact layouts.
Control input thresholds	V_IL ≤ 0.8 V, V_IH ≥ 2.0 V - guarantees reliable TTL-level compatibility with legacy microcontrollers and CPLDs.
Off-state capacitance (C_io(OFF))	4 pF max - minimizes crosstalk and loading on adjacent high-frequency traces in dense routing.

Pinout & Package

VQFN-14 (RGY) package: 3.5 mm × 3.5 mm, 0.5 mm pitch, exposed thermal pad, 1.0 mm max height. Designed for automated assembly and thermal efficiency in space-constrained embedded systems.

Pin/Terminal	Circuit Role	Design Meaning
1, 4, 7, 10	Output-enable (1OE, 2OE, 3OE, 4OE)	Active-low control inputs; tie high via pullup to ensure high-Z during power-up/down sequences.
2, 5, 12, 13	Port A (1A, 2A, 3A, 4A)	Bidirectional signal terminals connected to source side of internal FETs; support AC/DC coupling.
3, 6, 11, 14	Port B (1B, 2B, 3B, 4B)	Bidirectional signal terminals connected to drain side; electrically identical to Port A pins.
8	GND	Power ground reference for all internal circuitry and switch body terminals.
9	V_CC	Positive supply rail; must be decoupled locally with ≥0.1 µF ceramic capacitor near pin 9.
1, 14 (NC)	No internal connection	Unbonded pins; must remain unconnected and unpopulated on PCB layout.

Key Features

Feature	Design Value
Independent channel control	Four separate OE inputs allow selective activation of individual bus segments-critical for dynamic I/O resource allocation in multiprocessor systems.
Low on-resistance flatness	Δr_on < 2 Ω across channels and temperature - maintains consistent signal integrity and timing skew in parallel data paths.
TTL-compatible interface	Direct drive from 74LS, 74F, and microcontroller GPIO without level shifters-reduces BOM count and layout complexity.
Hot-swap capable	Supports −0.5 V to 7 V input range and clamp-current protection - enables safe insertion/removal in live backplane or modular system environments.
Small-footprint thermal design	47°C/W θ_JA with exposed pad - delivers 2.7× better thermal performance than SOIC-14, enabling sustained 128 mA per channel in 10 mm² area.

Applications

Memory Bus Isolation	FPGA I/O Expansion
Use Scenario: Isolating DRAM address/data lines between two memory controllers sharing a common bus. IC Role / Device Role / Timing Role: Bidirectional signal gate that prevents contention during arbitration, with sub-nanosecond propagation delay preserving setup/hold timing margins. Use Value: Enables dual-controller redundancy without adding bus buffers or complex arbitration logic-reducing latency and component count.	Use Scenario: Expanding FPGA I/O count by routing signals between bank-specific voltage domains (e.g., 3.3 V core ↔ 1.8 V peripheral). IC Role / Device Role / Timing Role: Level-agnostic analog switch providing rail-to-rail signal pass-through without translation delay or DC bias dependency. Use Value: Eliminates need for discrete level shifters while maintaining signal fidelity up to 500 MHz-cutting board area by 40% vs. buffer-based solutions.
PCI/ISA Legacy Interface	Test Equipment Signal Routing
Use Scenario: Enabling/disabling legacy ISA bus signals (e.g., IRQ, DMA) in modern PC-compatible embedded controllers. IC Role / Device Role / Timing Role: Low-latency bus switch replacing mechanical jumpers or relays-controlled via firmware-configurable GPIO. Use Value: Supports dynamic reconfiguration of hardware resources without physical intervention-improving field serviceability and reducing MTTR.	Use Scenario: Multiplexing calibration signals between DUT and measurement instruments in automated test fixtures. IC Role / Device Role / Timing Role: Precision analog switch with <4 pF off-capacitance and <5 Ω r_on, minimizing measurement path error and settling time. Use Value: Achieves ±0.1% gain accuracy and <10 ns switching transients-meeting Class II metrology requirements without active compensation.

Memory Bus Isolation

FPGA I/O Expansion

Use Scenario: Isolating DRAM address/data lines between two memory controllers sharing a common bus.

IC Role / Device Role / Timing Role: Bidirectional signal gate that prevents contention during arbitration, with sub-nanosecond propagation delay preserving setup/hold timing margins.

Use Value: Enables dual-controller redundancy without adding bus buffers or complex arbitration logic-reducing latency and component count.

Use Scenario: Expanding FPGA I/O count by routing signals between bank-specific voltage domains (e.g., 3.3 V core ↔ 1.8 V peripheral).

IC Role / Device Role / Timing Role: Level-agnostic analog switch providing rail-to-rail signal pass-through without translation delay or DC bias dependency.

Use Value: Eliminates need for discrete level shifters while maintaining signal fidelity up to 500 MHz-cutting board area by 40% vs. buffer-based solutions.

PCI/ISA Legacy Interface

Test Equipment Signal Routing

Use Scenario: Enabling/disabling legacy ISA bus signals (e.g., IRQ, DMA) in modern PC-compatible embedded controllers.

IC Role / Device Role / Timing Role: Low-latency bus switch replacing mechanical jumpers or relays-controlled via firmware-configurable GPIO.

Use Value: Supports dynamic reconfiguration of hardware resources without physical intervention-improving field serviceability and reducing MTTR.

Use Scenario: Multiplexing calibration signals between DUT and measurement instruments in automated test fixtures.

IC Role / Device Role / Timing Role: Precision analog switch with <4 pF off-capacitance and <5 Ω r_on, minimizing measurement path error and settling time.

Use Value: Achieves ±0.1% gain accuracy and <10 ns switching transients-meeting Class II metrology requirements without active compensation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74CBTD3384DBQR	10-channel, 3-state outputs with 3.3 V only supply (3.0–3.6 V); higher r_on (7 Ω typ)	Targeted at low-voltage LVTTL/LVCMOS systems; not suitable for 5 V mixed-signal interfaces	Select when operating exclusively at 3.3 V and requiring more channels in SSOP-24 footprint
74LVC1G3157DP	Single-channel SPDT switch, 1.65–5.5 V supply, 10 Ω r_on, SOT-363 package	Designed for point-of-load signal routing-not scalable to quad-bus architectures	Choose for ultra-low-power, single-line isolation where board area is constrained more than channel count

Compared with SN74CBT3125RGYR, SN74CBTD3384DBQR offers greater channel density but sacrifices 5 V compatibility and thermal efficiency, while 74LVC1G3157DP provides smaller size and wider voltage range at the cost of scalability and on-resistance performance-making SN74CBT3125RGYR optimal for 4-channel, 5 V-centric, thermally demanding designs.

Availability

SN74CBT3125RGYR is available at Aetrix Electronics and suitable for memory bus isolation, FPGA I/O expansion, PCI/ISA legacy interface, and test equipment signal routing requiring stable component supply and long-term production continuity.

Supply support for SN74CBT3125RGYR 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 technologies, with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74CBT3125RGYR belongs to TI's CBT (Crosspoint Bus Transceiver) family-designed specifically for high-speed, low-distortion signal routing in digital systems where timing integrity, power efficiency, and PCB real estate are critical constraints.

FAQ

What is the maximum continuous current rating per channel for SN74CBT3125RGYR?

The SN74CBT3125RGYR supports a continuous channel current of 128 mA per switch, verified under recommended operating conditions (V_CC = 4–5.5 V, T_A = −40°C to 85°C). This rating assumes proper PCB thermal design-including use of the exposed thermal pad-and accounts for junction temperature limits defined in the absolute maximum ratings table of the official datasheet.

Does SN74CBT3125RGYR require external pull-up resistors on its OE pins?

Yes, SN74CBT3125RGYR requires external pull-up resistors on all OE inputs to ensure high-impedance state during power-up or power-down. The minimum resistor value depends on the driver's current-sinking capability; TI recommends values between 4.7 kΩ and 10 kΩ for typical 5 V CMOS drivers, as specified in the functional description section of the SN74CBT3125RGYR datasheet.

Can SN74CBT3125RGYR operate with a 3.3 V supply voltage?

No, SN74CBT3125RGYR is not rated for 3.3 V operation. Its recommended operating supply range is 4.0 V to 5.5 V, and the absolute maximum rating for V_CC is 7 V. Operating below 4.0 V may result in undefined switching behavior, increased on-resistance, and failure to meet timing specifications-per the "Recommended Operating Conditions" table in the SN74CBT3125RGYR datasheet.

Is the RGY package of SN74CBT3125RGYR RoHS compliant?

Yes, the SN74CBT3125RGYR in the RGY (VQFN-14) package is RoHS compliant, as confirmed in TI's official Packaging Information document dated 31-Oct-2025. It uses NiPdAu lead finish and meets JEDEC MSL Level-1 standards for moisture sensitivity, with peak reflow temperature rated at 260°C.

How does SN74CBT3125RGYR handle negative input voltages?

SN74CBT3125RGYR tolerates input voltages down to −0.5 V, provided the input clamp current (I_K) remains within −50 mA. This capability enables safe interfacing with signals that may undershoot ground during fast edge transitions-common in high-speed digital systems-as documented in the Absolute Maximum Ratings table of the SN74CBT3125RGYR datasheet.

SN74CBT3125RGYR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74CBT

Package/Case:: 14-VFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Type:: Bus Switch

Circuit:: 1 x 1:1

Independent Circuits:: 4

Current - Output High, Low:: -

Voltage Supply Source:: Single Supply

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-VQFN (3.5x3.5)

SN74CBT3125RGYR FAQ

1.How can I place an order for SN74CBT3125RGYR through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74CBT3125RGYR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SN74CBT3125RGYR reliable?

The price and inventory of SN74CBT3125RGYR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3125RGYR is usually 5 days.

3.What payment methods are accepted for SN74CBT3125RGYR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3125RGYR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74CBT3125RGYR?

SN74CBT3125RGYR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74CBT3125RGYR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SN74CBT3125RGYR?

For technical support, including SN74CBT3125RGYR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3125RGYR requirements.

6.How does Aetrix verify that SN74CBT3125RGYR is sourced from the original manufacturer or authorized distributors?

All SN74CBT3125RGYR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74CBT3125RGYR meets industry standards.

7.What is the process for return or replacement of SN74CBT3125RGYR?

All SN74CBT3125RGYR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3125RGYR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SN74CBT3125RGYR part is unused and in its original packaging.

Return procedure for SN74CBT3125RGYR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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