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Texas Instruments SN74CB3T3125PWG4
- Part No.:
- SN74CB3T3125PWG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CB3T3125PWG4.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,951
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Product details
Overview
SN74CB3T3125PWG4 from Texas Instruments is a quadruple FET bus switch IC enabling bidirectional, low-latency level translation between 0–5 V signaling domains (e.g., 5-V TTL to 3.3-V LVTTL or 2.5-V CMOS), with 5-Ω typical ON-state resistance, 4.5 pF OFF-state I/O capacitance, and VCC-operating range of 2.3 V to 3.6 V. It serves as a voltage-tracking bus isolator in mixed-voltage digital interconnects.
For engineers reviewing the SN74CB3T3125PWG4 datasheet, SN74CB3T3125PWG4 pinout, SN74CB3T3125PWG4 application, or SN74CB3T3125PWG4 equivalent, key selection criteria include its 5-V-tolerant I/Os under powered-up/down conditions, Ioff partial-power-down support, near-zero propagation delay (<0.25 ns), and TSSOP-14 package compatibility with legacy 3.3-V system designs.
Technical Context
The SN74CB3T3125PWG4 implements four independent 1-bit FET-based analog switches, each controlled by an active-low enable (1OE–4OE). Its MOSFET architecture enables true bidirectional signal flow with no direction pin, while output voltage follows VCC-enabling level-shifting without external biasing. The device operates across 2.3 V–3.6 V VCC and tolerates up to 5.5 V on I/O pins regardless of power state.
Each switch exhibits rail-to-rail conduction when enabled (A↔B path), high-impedance isolation when disabled, and built-in undershoot clamp diodes on all I/O and control inputs. Ioff functionality prevents backflow current during partial power-down, satisfying JESD78 latch-up immunity (>250 mA) and JESD22 ESD robustness (±2000 V HBM, ±1000 V CDM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3 V to 3.6 V - Enables operation in 2.5-V and 3.3-V logic domains without level-shifter circuitry |
| ron (Typ) | 5 Ω - Minimizes voltage drop and timing skew across data paths at ≤128 mA per channel |
| Cio(OFF) | 4.5 pF - Reduces capacitive loading on upstream drivers and preserves signal integrity in high-speed buses |
| tpd (Max) | 0.25 ns at VCC = 3.3 V - Supports >1 GHz data rates with negligible propagation delay impact |
| Ioff (Max) | 10 μA at VCC = 0 V - Ensures safe hot-insertion and partial-power-down isolation in modular systems |
| VI/O Tolerance | 0 V to 5.5 V - Allows direct connection to 5-V buses while powered from 2.5-V or 3.3-V rails |
| ICC (Max) | 20 μA - Enables use in battery-powered portable equipment with ultra-low static power budget |
Pinout & Package
TSSOP-14 (PW) package: 5.00 mm × 4.40 mm body, 0.65 mm lead pitch, surface-mount, RoHS-compliant, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE–4OE | Active-low enable input | Individually controls ON/OFF state of each 1-bit switch; tied to VCC via pullup for power-up safety |
| 1A–4A, 1B–4B | Bidirectional I/O terminal pair | Passes signals in either direction when switch is enabled; high-impedance when disabled |
| VCC | Supply voltage input | Powers internal FET gates and clamp diodes; sets output voltage reference for level translation |
| GND | Ground reference | Common return path for all I/O and control signals; required for proper clamp diode operation |
Key Features
| Feature | Design Value |
|---|---|
| Output voltage tracks VCC | Enables seamless down-translation (e.g., 5-V input → 3.3-V output) without external resistors or regulators |
| 5-V-tolerant I/Os | Permits direct interfacing with legacy 5-V peripherals while operating from 2.5-V/3.3-V supplies, even during power-down |
| Bidirectional zero-delay switching | Eliminates direction-control logic and propagation delay penalties in full-duplex or shared-bus applications |
| Ioff partial-power-down support | Prevents damaging back-current flow when VCC is removed, supporting hot-swap and modular subsystem design |
| Low 4.5-pF OFF-state capacitance | Minimizes signal reflection and crosstalk in high-density PCB layouts with adjacent high-speed traces |
Applications
| USB Interface Isolation | Memory Bus Level Translation |
|---|---|
Use Scenario: Isolating 5-V USB transceiver signals from a 3.3-V microcontroller host in embedded peripheral modules. IC Role / Device Role / Timing Role: Bidirectional bus switch providing 5-V-to-3.3-V level translation on D+/D− lines with sub-nanosecond latency. Use Value: Eliminates need for discrete level-shifters or dual-supply transceivers, reducing BOM count and layout area. | Use Scenario: Interfacing a 5-V FPGA configuration PROM with a 2.5-V SoC memory controller. IC Role / Device Role / Timing Role: Four-channel voltage-translating bus switch enabling reliable address/data transfer across supply domains. Use Value: Maintains signal integrity at >100 MHz clock rates due to 5-Ω ron and 4.5-pF Cio(OFF), avoiding setup/hold violations. |
| PCIe Slot Power Management | Industrial I/O Module Signal Conditioning |
Use Scenario: Enabling hot-plug capability in PCIe add-in cards by isolating 3.3-V auxiliary power domain from 12-V main rail during insertion. IC Role / Device Role / Timing Role: Ioff-enabled bus switch disconnecting control lines during partial power-down sequences. Use Value: Prevents backfeed current into unpowered sections, meeting PCIe CEM specification for safe hot-insertion. | Use Scenario: Routing sensor analog/digital outputs (0–5 V) to a 3.3-V ADC and microcontroller in programmable logic controllers. IC Role / Device Role / Timing Role: Mixed-mode signal interface translating industrial field voltages to MCU-compatible logic levels. Use Value: Supports 0.8 V–5 V signaling without external biasing, simplifying firmware-driven voltage-range configuration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CB3Q3125PWR | Enhanced version with lower ron (3.5 Ω typ), improved ESD rating (±3000 V HBM), and extended temperature range (–40°C to 125°C) | Required for automotive or extended-temperature industrial deployments where SN74CB3T3125PWG4's 85°C max ambient is insufficient | Select when higher reliability, lower loss, or wider thermal margin is critical; not pin-compatible due to different thermal pad design |
| TS3A24159RGTR | Single-supply 2-channel SPDT analog switch with 0.7 Ω ron, but lacks 5-V tolerance and Ioff; requires VCC ≥ VI/O | Suitable only for same-supply-domain signal routing (e.g., 3.3-V to 3.3-V), not cross-voltage translation | Choose only for low-loss intra-rail switching where level-shifting is unnecessary; incompatible for 5-V-tolerant use cases |
Compared with SN74CB3T3125PWG4, SN74CB3Q3125PWR delivers superior performance in harsh environments but requires layout revision, while TS3A24159RGTR offers lower resistance only within single-supply systems-neither provides drop-in replacement capability for mixed-voltage translation.
Availability
SN74CB3T3125PWG4 is available at Aetrix Electronics and suitable for USB interface isolation, memory bus level translation, PCIe slot power management, and industrial I/O module signal conditioning requiring stable component supply across long-lifecycle embedded programs.
Supply support for SN74CB3T3125PWG4 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 designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and consumer applications.
The SN74CB3T3125PWG4 belongs to TI's CB3T bus switch family, engineered specifically for low-latency, bidirectional voltage translation in mixed-signal systems where power efficiency, I/O tolerance, and partial-power-down safety are mandatory.
FAQ
What is the maximum allowable input voltage on the I/O pins of the SN74CB3T3125PWG4?
The SN74CB3T3125PWG4 supports I/O voltages from 0 V to 5.5 V regardless of VCC state-enabling safe interfacing with 5-V buses even when the device is unpowered. This 5-V tolerance is guaranteed per absolute maximum ratings and verified under both powered-up and powered-down conditions, making SN74CB3T3125PWG4 suitable for hot-swap and mixed-voltage backplane applications.
Does the SN74CB3T3125PWG4 require external pull-up resistors on its OE pins?
Yes-TI recommends tying each OE pin (1OE–4OE) to VCC via a pullup resistor to ensure high-impedance state during power-up or power-down transitions. The minimum resistor value depends on the driving source's current-sinking capability; typical values range from 4.7 kΩ to 10 kΩ. This prevents undefined switch states and ensures deterministic isolation before firmware initialization of the SN74CB3T3125PWG4.
Can the SN74CB3T3125PWG4 be used for analog signal switching, such as audio or sensor signals?
No-the SN74CB3T3125PWG4 is specified and characterized exclusively for digital bus switching. Its FET structure lacks rail-to-rail analog linearity, has no guaranteed THD or bandwidth specs, and exhibits voltage-dependent ron that distorts analog waveforms. For analog signal routing, TI recommends dedicated analog switches like the TS5A23157 or TMUX1574; SN74CB3T3125PWG4 must be limited to digital logic-level translation and isolation.
What is the thermal performance of the SN74CB3T3125PWG4 in TSSOP-14 (PW) package?
In the TSSOP-14 (PW) package, the SN74CB3T3125PWG4 has a junction-to-ambient thermal resistance (RθJA) of 123.3°C/W. At maximum recommended ICC (20 μA) and typical ron (5 Ω) with 128 mA channel current, self-heating remains negligible (<0.1°C rise). No heatsink or thermal vias are required for standard operation, though PCB copper pour under the exposed pad (if present) further improves dissipation-though PW package lacks thermal pad unlike RGY.
How does the Ioff feature of the SN74CB3T3125PWG4 protect system-level circuits during partial power-down?
The Ioff feature limits leakage current to ≤10 μA when VCC = 0 V and I/O pins are biased to 0–5.5 V, preventing reverse current flow from powered domains into unpowered sections. This protects upstream drivers and downstream logic from latch-up or damage during staged power sequencing-critical in modular systems like server blades or field-replaceable units where SN74CB3T3125PWG4 isolates active and dormant subsystems.
SN74CB3T3125PWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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:
- 2.3V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-TSSOP
SN74CB3T3125PWG4 FAQ
1.How can I place an order for SN74CB3T3125PWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3T3125PWG4 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 SN74CB3T3125PWG4 reliable?
The price and inventory of SN74CB3T3125PWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3T3125PWG4 is usually 5 days.
3.What payment methods are accepted for SN74CB3T3125PWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3T3125PWG4 transactions.
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4.How is shipping managed for SN74CB3T3125PWG4?
SN74CB3T3125PWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3T3125PWG4 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 SN74CB3T3125PWG4?
For technical support, including SN74CB3T3125PWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3T3125PWG4 requirements.
6.How does Aetrix verify that SN74CB3T3125PWG4 is sourced from the original manufacturer or authorized distributors?
All SN74CB3T3125PWG4 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 SN74CB3T3125PWG4 meets industry standards.
7.What is the process for return or replacement of SN74CB3T3125PWG4?
All SN74CB3T3125PWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3T3125PWG4, 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 SN74CB3T3125PWG4 part is unused and in its original packaging.
Return procedure for SN74CB3T3125PWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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