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Texas Instruments SN74CB3T1G125DCKR
- Part No.:
- SN74CB3T1G125DCKR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 5-TSSOP, SC-70-5, SOT-353
- Datasheet:
-
SN74CB3T1G125DCKR.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 SC70-5
- Quantity:
- Payment:
- Shipping:
Inventory:10,654
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Product details
Overview
SN74CB3T1G125 from Texas Instruments is a single-bit 5-V-tolerant FET bus switch optimized for level translation and bidirectional signal isolation in mixed-voltage systems. It operates from 2.3 V to 3.6 V, delivers typ. 5 Ω ON-state resistance, supports 0–5 V signaling with 3.3-V VCC, and enables sub-0.25 ns propagation delay in USB interface and bus isolation applications.
For engineers reviewing the SN74CB3T1G125 datasheet, SN74CB3T1G125 pinout, SN74CB3T1G125 application, or SN74CB3T1G125 equivalent, key selection criteria include 5-V I/O tolerance with 2.5/3.3-V supply, Ioff partial-power-down support, low 5 pF OFF-state capacitance, and SC-70 (DCK) 5-pin package compatibility for space-constrained portable designs.
Technical Context
The SN74CB3T1G125 implements a single-channel FET-based transmission gate architecture with gate drive referenced to VCC, enabling voltage translation that tracks supply level. Its control logic uses TTL-compatible OE input (VIH = 2 V min at VCC ≥ 2.7 V) to enable/disable bidirectional conduction between A and B ports.
It integrates undershoot clamp diodes on all I/Os, supports Ioff protection during partial power-down, and maintains high-impedance isolation when powered off - critical for hot-swap and multi-rail system interoperability. The device meets JESD 17 latch-up immunity (>250 mA) and JESD 22 ESD ratings (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 across 2.5-V and 3.3-V logic domains without external level shifters. |
| ron (Typ) | 5 Ω - minimizes voltage drop and signal distortion under ±128 mA load, supporting clean high-speed data pass-through. |
| tpd (Max) | 0.25 ns at VCC = 3.3 V - ensures near-zero latency for timing-critical interfaces like USB 2.0 data lines. |
| Cio(OFF) (Typ) | 5 pF - reduces capacitive loading on upstream drivers and preserves signal integrity in high-frequency buses. |
| Ioff (Max) | 20 µA at VCC = 0 - prevents backflow current during system power sequencing, protecting unpowered rails. |
| IO Voltage Range | 0 V to 5.5 V - allows direct connection to 5-V peripherals (e.g., legacy USB transceivers) while powered from 3.3-V or 2.5-V supplies. |
| ESD Rating | 2000-V HBM, 1000-V CDM - meets industrial handling requirements without additional board-level protection. |
Pinout & Package
SN74CB3T1G125 is packaged in SC-70 (DCK), a 5-pin surface-mount package measuring 2.15 mm × 1.40 mm × 1.10 mm max height, optimized for high-density PCB layouts in portable electronics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | A port | Bidirectional data terminal connected to source-side logic (e.g., microcontroller GPIO); supports 0–5 V signaling regardless of VCC. |
| 2 | OE (Output Enable) | Active-low TTL/CMOS-compatible control input; must be pulled high via resistor during power-up to ensure default high-Z state. |
| 3 | GND | Ground reference for internal FET biasing and ESD protection network; requires low-inductance connection to system ground plane. |
| 4 | B port | Bidirectional data terminal connected to sink-side logic (e.g., USB PHY); mirrors A port voltage when enabled, isolated when OE = high. |
| 5 | VCC | Supply input for internal gate drive and level-shifting circuitry; sets output voltage translation reference and determines VIH/VIL thresholds. |
Key Features
| Feature | Design Value |
|---|---|
| 5-V-tolerant I/Os with 2.5/3.3-V supply | Enables direct interfacing between 5-V legacy peripherals and modern low-voltage SoCs without external translators. |
| Ioff partial-power-down protection | Blocks current flow between A/B ports when VCC = 0, preventing damage during hot-plug or rail sequencing events. |
| Sub-0.25 ns propagation delay | Maintains signal timing integrity in >100 MHz digital buses (e.g., USB D+/D−, memory address/data lines). |
| 5 pF OFF-state I/O capacitance | Minimizes loading on driving sources, preserving rise/fall times and reducing crosstalk in dense routing environments. |
| Mixed-mode signal operation | Supports simultaneous 0.8 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V, and 5 V logic levels on same port - ideal for heterogeneous FPGA I/O banks. |
Applications
| USB 2.0 Data Line Isolation | Low-Power Microcontroller I/O Expansion |
|---|---|
Use Scenario: Isolating D+ and D− lines between a 3.3-V host MCU and a 5-V USB peripheral during enumeration and data transfer. IC Role / Device Role / Timing Role: Bidirectional bus switch providing 5-V-tolerant signal pass-through with <0.25 ns delay and no level-shifter latency. Use Value: Eliminates need for dual-supply translators, reduces BOM count, and maintains USB 2.0 full-speed timing margins. | Use Scenario: Expanding GPIO count of an ultra-low-power ARM Cortex-M0+ MCU operating at 2.5 V while connecting to 3.3-V sensors and 5-V actuators. IC Role / Device Role / Timing Role: Voltage-translating bus switch enabling mixed-voltage I/O sharing without contention or shoot-through risk. Use Value: Enables single-chip sensor hub design with zero additional power supply rails and <5 µA quiescent current per channel. |
| FPGA I/O Bank Level Translation | Hot-Swappable Module Interface |
Use Scenario: Interfacing a Xilinx Artix-7 FPGA bank (1.8 V or 2.5 V) to external 3.3-V or 5-V communication ICs (e.g., RS-485 transceivers, CAN controllers). IC Role / Device Role / Timing Role: Directionless signal bridge with VCC-tracked output voltage and 5 pF OFF-capacitance to preserve signal edge rates. Use Value: Avoids timing skew from discrete translator ICs and simplifies PCB layout by removing separate VREF routing. | Use Scenario: Providing safe, isolated data path between a mainboard (3.3-V powered) and hot-pluggable daughter cards (5-V powered or unpowered). IC Role / Device Role / Timing Role: Ioff-enabled bus switch ensuring no current backfeed into mainboard during card insertion/removal. Use Value: Meets IEC 61000-4-2 Level 4 ESD robustness and eliminates need for mechanical interlocks or power sequencing controllers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT1G125DCKR | No 5-V tolerance; max VI/O = VCC + 0.5 V; higher ron (7 Ω typ); no Ioff support. | Suitable only for same-supply-domain isolation (e.g., 3.3-V-to-3.3-V), not mixed-voltage or hot-swap use cases. | Select when cost is primary constraint and 5-V tolerance/Ioff are unnecessary. |
| TS3A24157RGTR | 2-channel SPDT; 5-V tolerant; 0.9 Ω ron; supports 1.65–3.6 V VCC; includes enable polarity inversion option. | Offers dual-channel integration and lower ron but larger 16-pin QFN package; lacks SC-70 footprint compatibility. | Select when dual-switch functionality or sub-1 Ω ron justifies larger footprint and higher unit cost. |
Compared with SN74CBT1G125DCKR, the SN74CB3T1G125 provides essential 5-V I/O tolerance and Ioff for mixed-rail systems; versus TS3A24157RGTR, it offers identical 5-V tolerance in a smaller SC-70 package but with single-channel limitation and slightly higher ron.
Availability
SN74CB3T1G125 is available at Aetrix Electronics and suitable for USB interface isolation, low-power portable equipment, and FPGA I/O expansion requiring stable component supply and long-term production continuity.
Supply support for SN74CB3T1G125 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, energy efficiency, and system-level integration.
The SN74CB3T1G125 belongs to TI's CB3T family of low-voltage FET bus switches, designed specifically for voltage translation and signal isolation in battery-powered and mixed-supply digital systems.
FAQ
What is the maximum allowable input voltage on the A or B pins of the SN74CB3T1G125?
The SN74CB3T1G125 supports a data I/O voltage range of –0.5 V to 7 V per absolute maximum ratings, with recommended operation up to 5.5 V. When VCC is 3.3 V, the device reliably translates 5-V inputs to ~3.3-V outputs, making it suitable for interfacing 5-V peripherals without external clamping or translation circuitry. This rating applies regardless of OE state.
Does the SN74CB3T1G125 require external pull-up resistors on the OE pin?
Yes - to ensure a defined high-impedance state during power-up or power-down, OE should be tied to VCC through a pull-up resistor. TI recommends a minimum value determined by the driver's current-sinking capability; typical values range from 10 kΩ to 100 kΩ. Without this, undefined switching behavior or momentary short-circuits may occur during supply ramp.
Can the SN74CB3T1G125 be used for bidirectional level shifting between 1.8-V and 3.3-V logic domains?
No - the SN74CB3T1G125 does not support 1.8-V VCC operation; its specified VCC range is 2.3 V to 3.6 V. While its I/Os accept 0–5 V signals, the output voltage level follows VCC (≈VCC), so a 1.8-V domain cannot be driven directly. For 1.8-V ↔ 3.3-V translation, TI recommends the TXS0102 or similar auto-direction-sensing translators.
What is the thermal resistance (θJA) of the SN74CB3T1G125 in the DCK package?
The SN74CB3T1G125 in SC-70 (DCK) package has a junction-to-ambient thermal resistance (θJA) of 252°C/W, as specified in the Absolute Maximum Ratings table. This value assumes standard JEDEC test conditions (single-layer copper, 1-in² pad); actual performance improves with enhanced PCB copper area or thermal vias.
Is the SN74CB3T1G125 compatible with lead-free reflow processes?
Yes - the SN74CB3T1G125DCKR is RoHS-compliant with NIPDAU/SN lead finish and rated for MSL Level-1 (unlimited floor life) at peak reflow temperatures up to 260°C, fully compatible with standard lead-free soldering profiles per IPC/JEDEC J-STD-020.
SN74CB3T1G125DCKR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 5-TSSOP, SC-70-5, SOT-353
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Bus Switch
- Circuit:
- 1 x 1:1
- Independent Circuits:
- 1
- 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:
- SC-70-5
SN74CB3T1G125DCKR FAQ
1.How can I place an order for SN74CB3T1G125DCKR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3T1G125DCKR 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 SN74CB3T1G125DCKR reliable?
The price and inventory of SN74CB3T1G125DCKR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3T1G125DCKR is usually 5 days.
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4.How is shipping managed for SN74CB3T1G125DCKR?
SN74CB3T1G125DCKR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3T1G125DCKR 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 SN74CB3T1G125DCKR?
For technical support, including SN74CB3T1G125DCKR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3T1G125DCKR requirements.
6.How does Aetrix verify that SN74CB3T1G125DCKR is sourced from the original manufacturer or authorized distributors?
All SN74CB3T1G125DCKR 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 SN74CB3T1G125DCKR meets industry standards.
7.What is the process for return or replacement of SN74CB3T1G125DCKR?
All SN74CB3T1G125DCKR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3T1G125DCKR, 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 SN74CB3T1G125DCKR part is unused and in its original packaging.
Return procedure for SN74CB3T1G125DCKR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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