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Texas Instruments SN74CBT3125DBRE4
- Part No.:
- SN74CBT3125DBRE4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 14-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74CBT3125DBRE4.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 14SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,026
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Product details
Overview
SN74CBT3125DBRE4 from Texas Instruments is a quadruple FET bus switch IC with independent 1-bit switches, 5-Ω on-state resistance at 4 V, TTL-compatible control inputs, and operation from −40°C to 85°C. It enables bidirectional signal routing in low-voltage data paths such as memory address/data buses and peripheral I/O expansion.
For engineers reviewing the SN74CBT3125DBRE4 datasheet, SN74CBT3125DBRE4 pinout, SN74CBT3125DBRE4 application, or SN74CBT3125DBRE4 equivalent, key selection criteria include on-resistance stability across VCC (4–5.5 V), sub-1 ns propagation delay, high-impedance isolation during power sequencing, and SSOP-14 package compatibility with legacy board layouts.
Technical Context
This device implements four independent single-pole single-throw (SPST) analog switches using NMOS FETs with no internal level-shifting circuitry. Each switch connects its A and B terminals when the corresponding OE input is low (≤0.8 V), and presents >10⁹ Ω off-isolation when OE is high (≥2 V).
It operates without bias on the signal path - both A and B ports support rail-to-rail voltage swing from GND to VCC (4–5.5 V), with no DC blocking or directionality. The control logic uses standard TTL thresholds, eliminating need for external level translators in mixed-voltage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4 V to 5.5 V - supports stable operation across industrial 5-V supply tolerances and brownout conditions. |
| ron (Typ) | 5 Ω at VCC = 4 V, II = 64 mA - ensures minimal voltage drop and signal distortion in 3.3-V/5-V digital bus applications. |
| tpd (Max) | 0.35 ns at VCC = 4 V, CL = 50 pF - enables use in high-speed parallel interfaces up to ~1 GHz effective bandwidth. |
| VIH/VIL | 2 V / 0.8 V - fully compatible with standard TTL logic families without pull-up/pull-down resistors. |
| Off-State Isolation | >10⁹ Ω - prevents leakage-induced crosstalk between inactive bus segments during hot-swap or power-gating events. |
| Supply Current (ICC) | 3 μA max at VCC = 5.5 V - negligible quiescent load for battery-backed or always-on subsystems. |
| ESD Rating | ±2 kV HBM - meets basic handling robustness requirements for assembly and field service environments. |
Pinout & Package
SN74CBT3125DBRE4 is housed in a 14-pin SSOP (Shrink Small-Outline Package) with 0.65 mm lead pitch, 5.3 mm body width, and 1.75 mm maximum height - compatible with automated SMT placement and reflow profiles per JEDEC MO-150.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 7, 10 | OE (Output Enable) | Active-low control for each of four independent switches; tie to VCC via pull-up for power-up high-Z safety. |
| 2, 5, 12, 15 | A Port | Input/output terminal for first side of switch; bidirectional, rail-to-rail capable (GND to VCC). |
| 3, 6, 13, 16 | B Port | Input/output terminal for second side of switch; electrically identical to A port, no directionality. |
| 8 | GND | Power return reference for all switches and control logic; must be low-impedance for signal integrity. |
| 14 | VCC | Positive supply for switch FETs and control circuitry; bypassing with 0.1 μF ceramic near pin is recommended. |
| 11, 14 | NC | No internal connection - left unconnected; not used for thermal or mechanical anchoring. |
Key Features
| Feature | Design Value |
|---|---|
| Independent 1-bit switching | Four isolated SPST paths allow selective enable/disable of individual data lines without affecting others - critical for partial bus gating. |
| 5-Ω typical on-resistance | Minimizes insertion loss and timing skew in parallel bus traces, preserving signal edge rates under 100 mA load. |
| TTL-compatible control | Eliminates need for level shifters when interfacing with legacy microcontrollers, CPLDs, or 5-V logic families. |
| High-impedance power-up state | OE pins default to high-Z when un-driven; pull-up resistor ensures safe disable until system firmware asserts control. |
| Rail-to-rail analog switching | Supports bidirectional transmission of any logic-level signal (0–VCC) without clamping or distortion - usable in mixed-signal I/O buffers. |
Applications
| Memory Address Bus Isolation | Peripheral I/O Multiplexing |
|---|---|
Use Scenario: Isolating CPU address lines from multiple memory banks (SRAM, Flash, ROM) to prevent contention during bank switching. IC Role / Device Role / Timing Role: Bidirectional analog switch enabling/disabling physical connection between processor and selected memory device. Use Value: Prevents address-line shorting and reduces dynamic power by cutting off unused memory segments during idle cycles. | Use Scenario: Sharing GPIO pins between UART, SPI, and I²C peripherals on a microcontroller with limited pin count. IC Role / Device Role / Timing Role: Signal-path selector that routes MCU pins to one interface at a time while maintaining logic-level compatibility. Use Value: Enables flexible hardware reuse without firmware-level protocol arbitration or external level translation. |
| Hot-Swappable Module Interface | Test Access Point Switching |
Use Scenario: Enabling safe insertion/removal of daughterboards carrying FPGA configuration data or sensor arrays in powered-backplane systems. IC Role / Device Role / Timing Role: Power-sequencing-aware bus gate that isolates module signals until VCC and OE are stable. Use Value: Prevents back-driving of host controller I/O during plug-in events, avoiding latch-up or data corruption. | Use Scenario: Routing JTAG or SWD debug signals between multiple ASICs or SoCs on a shared test harness. IC Role / Device Role / Timing Role: Low-latency, low-capacitance signal router controlled by test sequencer to select active DUT. Use Value: Reduces test fixture complexity and eliminates manual jumper changes, improving production test repeatability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384DBR | 8-channel, higher Ron (~7 Ω), supports 3.3-V only VCC (2.3–3.6 V), includes output-enable inversion option. | Designed for low-voltage mobile I/O expansion; not suitable for 5-V legacy systems. | Select when migrating to 3.3-V-only designs requiring higher channel density and tighter layout footprint. |
| 74LVC1G3157DP | Single-channel, 5-V tolerant, Ron = 6 Ω typical, smaller X2SON-6 package, lower ICC (1 μA). | Optimized for point-of-load signal routing rather than multi-bit bus gating; lacks quad integration. | Choose for space-constrained PCBs where only one line needs switching and ultra-low static current is mandatory. |
Compared with SN74CBT3125DBRE4, SN74CBTD3384DBR offers greater channel count but requires full 3.3-V system redesign, while 74LVC1G3157DP trades integration for size and power efficiency - neither provides direct pin-for-pin replacement in existing SSOP-14 layouts.
Availability
SN74CBT3125DBRE4 is available at Aetrix Electronics and suitable for memory bus isolation, peripheral multiplexing, hot-swap interface design, and test access routing requiring stable component supply and long-term industrial availability.
Supply support for SN74CBT3125DBRE4 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 SN74CBT3125DBRE4 belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered for low-latency, low-distortion signal routing in high-speed digital systems where bus contention and power sequencing reliability are critical.
FAQ
What is the maximum continuous current rating per channel of the SN74CBT3125DBRE4?
The SN74CBT3125DBRE4 supports a continuous channel current of 128 mA per switch, verified under absolute maximum ratings. This allows reliable operation driving standard CMOS loads and moderate fan-out without thermal derating at ambient temperatures up to 85°C. Exceeding this limit risks permanent degradation of on-resistance and switching lifetime.
Does the SN74CBT3125DBRE4 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 SN74CBT3125DBRE4 must be tied to VCC through an external pull-up resistor. The minimum value depends on the driver's current-sinking capability; TI recommends values between 4.7 kΩ and 10 kΩ for typical 5-V systems with standard logic drivers.
Can the SN74CBT3125DBRE4 operate with a 3.3-V supply voltage?
No - the SN74CBT3125DBRE4 has a specified minimum VCC of 4 V per recommended operating conditions. Operation below 4 V violates datasheet specifications and may result in undefined switching behavior, increased on-resistance, or failure to recognize TTL logic levels. For 3.3-V systems, consider SN74CBTD3384DBR or 74LVC1G3157DP instead.
Is the SN74CBT3125DBRE4 pin-compatible with other packages in the same family?
Yes - the SN74CBT3125DBRE4 shares the standard '125-type pinout with SOIC (D), SSOP (DB), TSSOP (PW), TVSOP (DGV), and QFN (RGY) variants. All follow identical 1–14 pin numbering and function mapping, allowing direct PCB footprint substitution among these packages without schematic or layout changes.
What is the thermal performance difference between the DB and RGY packages of the SN74CBT3125DBRE4?
The SSOP-14 (DB) package of the SN74CBT3125DBRE4 has a θJA of 96°C/W, while the VQFN-14 (RGY) variant achieves 47°C/W - more than 2× better thermal resistance. This makes the RGY version suitable for higher ambient temperature or higher-current applications where junction temperature rise must remain below 125°C, though it requires different PCB land patterns and reflow profiles.
SN74CBT3125DBRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 14-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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-SSOP
SN74CBT3125DBRE4 FAQ
1.How can I place an order for SN74CBT3125DBRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3125DBRE4 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 SN74CBT3125DBRE4 reliable?
The price and inventory of SN74CBT3125DBRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3125DBRE4 is usually 5 days.
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Once your SN74CBT3125DBRE4 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 SN74CBT3125DBRE4?
For technical support, including SN74CBT3125DBRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3125DBRE4 requirements.
6.How does Aetrix verify that SN74CBT3125DBRE4 is sourced from the original manufacturer or authorized distributors?
All SN74CBT3125DBRE4 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 SN74CBT3125DBRE4 meets industry standards.
7.What is the process for return or replacement of SN74CBT3125DBRE4?
All SN74CBT3125DBRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3125DBRE4, 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 SN74CBT3125DBRE4 part is unused and in its original packaging.
Return procedure for SN74CBT3125DBRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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