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Texas Instruments SN74CB3Q3125DBQR
- Part No.:
- SN74CB3Q3125DBQR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74CB3Q3125DBQR.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:573
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Product details
Overview
SN74CB3Q3125DBQR from Texas Instruments is a quadruple 1-bit FET bus switch optimized for high-bandwidth signal routing in 2.5V/3.3V systems. It delivers rail-to-rail switching (0V–5V with 3.3V VCC), 3Ω typical ON-state resistance, <0.2 ns propagation delay, and 5V-tolerant I/Os - enabling clean signal gating in USB, optical networking, and PBX backplanes.
For engineers reviewing the SN74CB3Q3125DBQR datasheet, SN74CB3Q3125DBQR pinout, SN74CB3Q3125DBQR application, or SN74CB3Q3125DBQR equivalent, key selection criteria include its 500MHz bandwidth, Ioff-enabled partial-power-down capability, low 4pF OFF-state capacitance, bidirectional operation, and compatibility with TTL/3.3V/5V control logic.
Technical Context
The SN74CB3Q3125DBQR integrates four independent FET switches, each controlled by an active-low OE input. Its internal charge pump elevates gate voltage to maintain flat ron across 0–5V signal swing, supporting true rail-to-rail analog/digital signal pass-through without level-shifting circuitry.
Each channel operates bidirectionally with near-zero propagation delay (0.12–0.2 ns), minimal loading (Cio(OFF) = 4 pF typ), and robust 5V tolerance on I/O pins regardless of VCC state (2.3V–3.6V). Ioff protection prevents backflow during partial power-down, satisfying JESD78 Class II latch-up requirements (>100 mA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3V to 3.6V - enables interoperability with 2.5V and 3.3V logic domains while maintaining full 5V I/O tolerance. |
| ron (Typ) | 3Ω at VCC = 3.3V - ensures minimal insertion loss and signal distortion for high-speed digital and analog signals up to 500MHz. |
| Cio(OFF) | 4 pF typical - reduces capacitive loading on shared buses, preserving signal integrity and timing margins in dense PCB layouts. |
| Propagation Delay | 0.12–0.2 ns - enables sub-nanosecond timing-critical applications such as high-speed interconnect isolation and clock domain bridging. |
| I/O Voltage Range | 0V to 5.5V - supports mixed-voltage signaling (0.8V, 1.2V, 1.5V, 1.8V, 2.5V, 3.3V, 5V) without external level shifters. |
| fOE Max | 20 MHz - allows fast enable/disable cycling for dynamic bus resource allocation in programmable logic and FPGA interfaces. |
| Ioff Protection | Active at VCC = 0V - blocks damaging current flow between powered and unpowered system sections during hot-swap or partial shutdown. |
Pinout & Package
SN74CB3Q3125DBQR uses a 16-pin SSOP (DBQ) package measuring 4.90 mm × 3.90 mm with exposed pad thermal enhancement. Pin 1 is marked via notch or dot; pin numbering follows standard SSOP convention (counterclockwise from top-left corner).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OE, 4 OE, 8 OE, 12 OE | Active-low output enable (4 channels) | Individually controls ON/OFF state per 1-bit switch; tied high via pullup for power-up high-impedance safety. |
| 2A, 3A, 5A, 6A, 10A, 11A, 13A, 14A | Data I/O port A (8 pins) | Bidirectional signal path endpoint; accepts 0–5.5V signals regardless of VCC state. |
| 1B, 4B, 7B, 9B, 15B, 16B | Data I/O port B (6 pins) | Bidirectional signal path endpoint; paired with corresponding A pins (e.g., 1A↔1B); NC pins unused. |
| GND (Pin 8) | Ground reference | Primary return path for switch conduction and supply current; must be low-inductance connection for signal integrity. |
| VCC (Pin 16) | Power supply | Supplies internal charge pump and logic; requires local 0.1 µF bypass capacitor placed adjacent to pin. |
| NC (Pins 1, 9) | No internal connection | Unbonded die pads; must remain unconnected on PCB to avoid parasitic coupling or ESD path disruption. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail analog/digital switching | Supports 0V–5V signal pass-through with 3.3V VCC, eliminating need for external level translators in mixed-voltage systems. |
| Charge-pump-enhanced ron | Maintains flat 3–8 Ω ON-resistance across full input voltage range, ensuring consistent signal attenuation and timing behavior. |
| 5V-tolerant I/Os (powered/unpowered) | Enables safe interface to 5V peripherals even when device is unpowered or operating at 2.5V, critical for hot-plug and legacy compatibility. |
| Ioff partial-power-down mode | Prevents back-current flow between live and dead domains, meeting JESD78 Class II latch-up immunity (>100 mA) for system-level reliability. |
| Low OFF-state capacitance | 4 pF typical isolates inactive channels effectively, minimizing crosstalk and loading on high-speed buses like USB 2.0 or EPON control lines. |
Applications
| USB 2.0 Interface Isolation | Optical Networking Backplane |
|---|---|
|
Use Scenario: Isolating USB D+/D− lines between host controller and peripheral port during enumeration or fault conditions. IC Role / Device Role / Timing Role: Bidirectional signal gate with sub-0.2 ns delay and 5V tolerance, preserving USB 2.0 eye diagram integrity. Use Value: Enables hot-plug-safe port sharing without signal degradation or level-shifter overhead, reducing BOM count and layout complexity. |
Use Scenario: Routing differential clock or data lanes between FPGA transceivers and SFP+ modules in EPON video-over-fiber equipment. IC Role / Device Role / Timing Role: Low-capacitance, rail-to-rail bus switch providing 500MHz bandwidth for 1.25 Gbps serial links. Use Value: Maintains signal fidelity across voltage-domain boundaries (e.g., 2.5V FPGA ↔ 3.3V optics) while supporting partial-power-down during module sleep. |
| PBX Digital Signal Routing | WiMAX Baseband Switching |
|
Use Scenario: Dynamically connecting DSP resources to multiple TDM voice channels in private branch exchange systems. IC Role / Device Role / Timing Role: Four independent 1-bit switches enabling flexible time-slot assignment with nanosecond-level timing precision. Use Value: Delivers deterministic latency and minimal jitter accumulation across 8-channel TDM paths, meeting ITU-T G.703 jitter specs. |
Use Scenario: Enabling/disabling RF front-end calibration paths or antenna diversity switching in WiMAX infrastructure base stations. IC Role / Device Role / Timing Role: High-bandwidth analog switch supporting DC–500MHz operation for IF/RF signal path control. Use Value: Provides low-distortion, low-leakage signal gating for calibration loops without introducing harmonic artifacts or DC offset drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3125DBQR | Higher ron (6Ω typ), no charge pump, 2.5V–5.5V VCC range, lower bandwidth (300MHz). | Lacks rail-to-rail support at 2.5V VCC; less suitable for 0–3.3V signaling with tight timing budgets. | Choose when cost sensitivity outweighs need for sub-0.2 ns delay or ultra-flat ron across voltage range. |
| PI3CH400LE | 4Ω ron, 5V-tolerant, but only 200MHz bandwidth and no Ioff protection; 3.3V-only VCC. | Not rated for partial-power-down operation; unsuitable for hot-swap or mixed-power-domain isolation. | Acceptable for static 3.3V-only routing where bandwidth ≤200MHz and power sequencing is fully controlled. |
Compared with SN74CB3Q3125DBQR, SN74CBT3125DBQR trades bandwidth and ron flatness for wider VCC flexibility, while PI3CH400LE sacrifices Ioff and bandwidth for lower cost - making SN74CB3Q3125DBQR the optimal choice for high-reliability, mixed-voltage, nanosecond-critical signal gating.
Availability
SN74CB3Q3125DBQR is available at Aetrix Electronics and suitable for USB interface isolation, optical networking backplanes, PBX digital signal routing, WiMAX baseband switching, and EPON video-over-fiber systems requiring stable component supply across industrial temperature ranges (–40°C to +85°C).
Supply support for SN74CB3Q3125DBQR 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 high-performance signal conditioning and interface solutions.
The SN74CB3Q3125DBQR belongs to TI's CB3Q family of high-bandwidth FET bus switches, designed specifically for low-distortion, rail-to-rail signal routing in broadband communications, optical networking, and multi-voltage digital systems.
FAQ
What is the maximum signal frequency supported by SN74CB3Q3125DBQR?
SN74CB3Q3125DBQR supports up to 500MHz signal bandwidth, verified by its high-bandwidth data path architecture and low 4pF OFF-state capacitance. This makes SN74CB3Q3125DBQR suitable for USB 2.0, EPON, and other high-speed digital interfaces where signal integrity above 200MHz is required. Performance remains stable across its full 0–5.5V I/O voltage range.
Does SN74CB3Q3125DBQR support partial-power-down operation?
Yes, SN74CB3Q3125DBQR features Ioff circuitry that actively blocks current backflow when VCC = 0V, enabling safe partial-power-down operation. This protects downstream components during hot-swap events or system-level power sequencing - a key requirement validated per JESD78 Class II latch-up testing (>100 mA).
Can SN74CB3Q3125DBQR interface between 2.5V and 5V logic domains?
Yes, SN74CB3Q3125DBQR supports true rail-to-rail switching: with 2.5V VCC, it passes 0–3.3V signals; with 3.3V VCC, it passes 0–5V signals. Its 5V-tolerant I/Os operate correctly whether the device is powered or unpowered, making SN74CB3Q3125DBQR ideal for mixed-voltage board-level interfacing without external level shifters.
What is the typical ON-state resistance of SN74CB3Q3125DBQR and how does it vary?
SN74CB3Q3125DBQR has a typical ON-state resistance (ron) of 3Ω at VCC = 3.3V, with flat characteristics across input voltage (0–5V). At VCC = 2.5V, ron remains low (4–6Ω typ), enabled by its internal charge pump. This flat ron profile ensures consistent signal attenuation and minimal timing skew - a defining feature of SN74CB3Q3125DBQR versus non-charge-pump alternatives.
How is the pinout of SN74CB3Q3125DBQR configured for 16-pin SSOP?
SN74CB3Q3125DBQR uses a 16-pin SSOP (DBQ) package with pins 1 and 9 designated as NC (no internal connection), pin 8 as GND, pin 16 as VCC, and four active-low OE inputs (pins 1, 4, 8, 12). Data I/O pairs are arranged as (2A/1B), (3A/4B), (5A/7B), (6A/9B), (10A/15B), (11A/16B), with remaining pins unused. Pin 1 is identified by package notch or dot marking.
SN74CB3Q3125DBQR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 16-SSOP
SN74CB3Q3125DBQR FAQ
1.How can I place an order for SN74CB3Q3125DBQR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3Q3125DBQR 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 SN74CB3Q3125DBQR reliable?
The price and inventory of SN74CB3Q3125DBQR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3Q3125DBQR is usually 5 days.
3.What payment methods are accepted for SN74CB3Q3125DBQR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3Q3125DBQR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74CB3Q3125DBQR?
SN74CB3Q3125DBQR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3Q3125DBQR 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 SN74CB3Q3125DBQR?
For technical support, including SN74CB3Q3125DBQR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3Q3125DBQR requirements.
6.How does Aetrix verify that SN74CB3Q3125DBQR is sourced from the original manufacturer or authorized distributors?
All SN74CB3Q3125DBQR 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 SN74CB3Q3125DBQR meets industry standards.
7.What is the process for return or replacement of SN74CB3Q3125DBQR?
All SN74CB3Q3125DBQR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3Q3125DBQR, 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 SN74CB3Q3125DBQR part is unused and in its original packaging.
Return procedure for SN74CB3Q3125DBQR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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