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Texas Instruments SN74CBT3125PWG4
- Part No.:
- SN74CBT3125PWG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CBT3125PWG4.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,465
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Product details
Overview
SN74CBT3125PWG4 from Texas Instruments is a quadruple FET bus switch IC with independent 5-Ω bidirectional analog/digital signal paths, TTL-compatible control inputs, and 4.0–5.5 V supply operation-used for high-speed data routing in memory expansion, peripheral multiplexing, and level-translating I/O interfaces.
For engineers reviewing the SN74CBT3125PWG4 datasheet, SN74CBT3125PWG4 pinout, SN74CBT3125PWG4 application, or SN74CBT3125PWG4 equivalent, key selection considerations include on-resistance (5–7 Ω), propagation delay (≤0.35 ns at 4 V), enable/disable timing (≤6 ns), thermal resistance (113°C/W), and TSSOP-14 package compatibility with space-constrained PCB layouts.
Technical Context
This device 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 terminals when OE is low (L), and presents high-impedance isolation when OE is high (H).
It operates as a passive analog switch with no internal logic or level-shifting circuitry-signal integrity depends on external biasing and load capacitance (CL = 50 pF specified). The design supports bidirectional signal flow, requires no power sequencing constraints beyond VCC tie-high for OE during power-up, and exhibits rail-to-rail voltage handling (−0.5 V to 7 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.0–5.5 V - defines compatible logic families (TTL/5-V CMOS) and maximum signal swing. |
| On-State Resistance (ron) | 5–7 Ω (typ) - ensures minimal insertion loss and voltage drop (<320 mV at 64 mA) for analog/digital signals. |
| Propagation Delay (tpd) | ≤0.35 ns at VCC = 4 V - enables sub-nanosecond signal routing critical for high-speed bus arbitration. |
| Enable/Disable Time (ten/tdis) | ≤6 ns / ≤5.1 ns - guarantees fast channel switching for dynamic bus sharing and hot-swap applications. |
| Input Capacitance (Ci) | 3 pF - minimizes loading on upstream drivers and preserves signal edge rates. |
| Off-State Capacitance (Cio) | 4 pF - reduces crosstalk and capacitive feedthrough between isolated channels. |
| Channel Current Rating | 128 mA continuous - supports robust drive capability for buffered address/data lines. |
Pinout & Package
TSSOP-14 (PW) package: 4.4 mm × 5.0 mm body, 0.65 mm pitch, 1.2 mm max height, exposed pad not present, JEDEC MO-153 compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 7, 10 (1OE–4OE) | Output-enable control input | Active-low enable per channel; must be pulled to VCC for power-up high-Z state. |
| 2, 5, 12, 15 (1A–4A) | Port A terminal | Bidirectional signal node connected through FET to corresponding B port when OE = L. |
| 3, 6, 13, 16 (1B–4B) | Port B terminal | Bidirectional signal node; identical electrical behavior to Port A; no polarity preference. |
| 8 (GND) | Ground reference | Return path for all internal FETs and control circuitry; must be low-inductance connection. |
| 14 (VCC) | Power supply | Single 4–5.5 V supply powers all four switches and control logic; no separate analog/digital rails. |
Key Features
| Feature | Design Value |
|---|---|
| 5-Ω low on-resistance | Enables <320 mV voltage drop at 64 mA, preserving signal amplitude across high-speed digital buses. |
| TTL-compatible control inputs | Accepts standard 0.8 V/2.0 V VIH/VIL thresholds without level shifters-simplifies interface with legacy microcontrollers. |
| Sub-nanosecond propagation delay | 0.25–0.35 ns tpd allows use in >1 GHz clock domain routing where timing skew must be minimized. |
| Independent per-channel enable | Supports selective bus segmentation-e.g., enabling only memory address lines while disabling data lines during refresh cycles. |
| Rail-to-rail signal handling | −0.5 V to 7 V VI range permits safe operation with mixed-voltage systems (e.g., 3.3 V logic driving 5 V peripherals). |
Applications
| Memory Expansion Interface | Peripheral Multiplexing |
|---|---|
Use Scenario: Adding external SRAM or Flash to an MCU with limited address/data pins by time-division sharing of bus lines. IC Role / Device Role / Timing Role: Bidirectional analog switch isolating shared address/data lines between MCU and two memory devices. Use Value: Eliminates need for glue logic or complex bus controllers; 5 Ω Ron and 0.35 ns tpd prevent timing violations in 20+ MHz parallel memory access. | Use Scenario: Sharing UART, SPI, or GPIO lines among multiple sensors or actuators on a compact industrial controller PCB. IC Role / Device Role / Timing Role: Channel-selectable signal path router enabling one physical interface to serve multiple peripherals sequentially. Use Value: Reduces connector count and board real estate; 6 ns enable time allows rapid reconfiguration between sensor reads without firmware overhead. |
| Level-Translating I/O Bridge | Hot-Swap Bus Isolation |
Use Scenario: Interfacing 3.3 V FPGA I/O to 5 V legacy peripherals without damaging either side. IC Role / Device Role / Timing Role: Passive voltage-tolerant switch placed between mismatched logic domains, with OE tied to system reset. Use Value: No active translation circuitry required; −0.5 V to 7 V VI rating protects both sides during power sequencing mismatches. | Use Scenario: Safely inserting/removing daughterboards in live backplane systems without disrupting main CPU bus operation. IC Role / Device Role / Timing Role: High-Z isolation gate activated only after mechanical insertion is complete and power stabilized. Use Value: Prevents bus contention and glitch injection; 128 mA current rating handles transient surge currents during plug-in events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384PWR | 8-channel, higher Ron (7–10 Ω), supports 3.3 V only (VCC = 2.3–3.6 V), includes power-down mode. | Targeted at low-voltage embedded systems; unsuitable for 5 V buses or sub-5 Ω requirements. | Select when consolidating more channels into one package and operating strictly at 3.3 V. |
| 74LVC1G3157DP,125 | Single-channel, lower Ron (3–5 Ω), 1.65–5.5 V VCC, smaller X2SON-6 package. | Used for point-of-load signal routing rather than quad-bus management; lacks independent OE per channel. | Choose for ultra-compact single-line isolation where board space is critical and channel independence is unnecessary. |
Compared with SN74CBT3125PWG4, SN74CBTD3384PWR offers greater channel density but sacrifices voltage range and on-resistance performance, while 74LVC1G3157DP,125 provides superior Ron and size efficiency at the cost of scalability and per-channel control granularity.
Availability
SN74CBT3125PWG4 is available at Aetrix Electronics and suitable for memory expansion, peripheral multiplexing, level-translating I/O bridges, and hot-swap bus isolation requiring stable component supply across industrial and embedded production programs.
Supply support for SN74CBT3125PWG4 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74CBT3125PWG4 belongs to TI's CBT (Crossbar Bus Transceiver) logic family-designed specifically for high-speed, low-latency, bidirectional signal routing in memory and peripheral interconnect applications.
FAQ
What is the maximum signal voltage that SN74CBT3125PWG4 can safely pass?
The SN74CBT3125PWG4 supports input voltages from −0.5 V to 7 V, independent of VCC. This rail-to-rail capability allows it to pass signals exceeding the supply rail-such as 5 V signals on a 3.3 V system-without damage or distortion, provided clamp-current limits (±50 mA) are not exceeded.
Does SN74CBT3125PWG4 require external pull-up resistors on its OE pins?
Yes-TI recommends tying each OE pin to VCC via a pull-up resistor to ensure high-impedance state during power-up or power-down. The minimum resistor value depends on the driver's current-sinking capability; typical values range from 1 kΩ to 10 kΩ for standard logic drivers.
Can SN74CBT3125PWG4 be used for analog signal switching, such as audio or sensor signals?
Yes-the SN74CBT3125PWG4 functions as a bidirectional analog switch with flat on-resistance (5–7 Ω) and low off-capacitance (4 pF), making it suitable for low-frequency analog signals like audio, thermistor readings, or potentiometer wiper routing-provided signal amplitudes stay within the −0.5 V to 7 V range and bandwidth remains below ~100 MHz.
What is the thermal resistance (θJA) of SN74CBT3125PWG4 in its TSSOP-14 package?
The SN74CBT3125PWG4 in the PW (TSSOP-14) package has a junction-to-ambient thermal resistance (θJA) of 113°C/W under standard JEDEC test conditions. This value assumes a 2-layer PCB with 1 in² copper pour; actual performance improves with enhanced layout (e.g., thermal vias, larger ground planes).
Is SN74CBT3125PWG4 pin-compatible with other '125-type bus switches like SN74LS125?
No-while SN74CBT3125PWG4 uses the standard '125-type pinout (D, DB, DGV, PW, RGY packages), it is functionally distinct from SN74LS125: the CBT version is a passive FET switch (bidirectional, low Ron), whereas LS125 is a 3-state buffer (unidirectional, active logic). Pin compatibility does not imply functional or electrical interchangeability.
SN74CBT3125PWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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-TSSOP
SN74CBT3125PWG4 FAQ
1.How can I place an order for SN74CBT3125PWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3125PWG4 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 SN74CBT3125PWG4 reliable?
The price and inventory of SN74CBT3125PWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3125PWG4 is usually 5 days.
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Once your SN74CBT3125PWG4 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 SN74CBT3125PWG4?
For technical support, including SN74CBT3125PWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3125PWG4 requirements.
6.How does Aetrix verify that SN74CBT3125PWG4 is sourced from the original manufacturer or authorized distributors?
All SN74CBT3125PWG4 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 SN74CBT3125PWG4 meets industry standards.
7.What is the process for return or replacement of SN74CBT3125PWG4?
All SN74CBT3125PWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3125PWG4, 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 SN74CBT3125PWG4 part is unused and in its original packaging.
Return procedure for SN74CBT3125PWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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