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Texas Instruments SN74CB3Q3257DBQR
- Part No.:
- SN74CB3Q3257DBQR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74CB3Q3257DBQR.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,204
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Product details
Overview
SN74CB3Q3257DBQR from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer optimized for high-bandwidth bus switching, featuring 4 Ω typical on-state resistance (ron), 500 MHz bandwidth, and rail-to-rail 0–5 V signal support at 3.3 V VCC. It enables bidirectional data flow with near-zero propagation delay (0.2 ns typical) and supports partial-power-down via Ioff in systems like optical networking and IP telephony.
For engineers reviewing the SN74CB3Q3257DBQR datasheet, SN74CB3Q3257DBQR pinout, SN74CB3Q3257DBQR application, or SN74CB3Q3257DBQR equivalent, key selection criteria include 5 V-tolerant I/Os under powered-up/down conditions, low 3.5 pF off-state capacitance for minimal signal distortion, fast 20 MHz enable switching, and SSOP-16 package compatibility with industrial temperature range (–40°C to 85°C).
Technical Context
The SN74CB3Q3257DBQR implements four independent 1-of-2 analog/digital switches using charge-pump-enhanced FETs to maintain flat ron across 2.3–3.6 V VCC, enabling stable impedance matching for broadband signals. Each channel features separate select (S) and output-enable (OE) control with active-low OE logic.
Its architecture supports true bidirectional operation without direction pins, zero DC bias requirement, and 5 V tolerance on all I/Os regardless of VCC state-critical for level-shifting between mixed-voltage domains (e.g., 1.8 V/3.3 V/5 V buses) in USB interface and EPON equipment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3 V to 3.6 V - Enables interoperability with 2.5 V and 3.3 V logic families while maintaining 5 V I/O tolerance. |
| ron (Typical) | 4 Ω - Ensures minimal voltage drop and signal attenuation for high-fidelity analog/digital bus switching. |
| Bandwidth | 500 MHz - Supports high-speed serial links including USB 2.0 and video-over-fiber applications. |
| Cio(OFF) | 3.5 pF typical - Reduces capacitive loading to preserve signal integrity and edge rate in multi-drop buses. |
| tpd | 0.2 ns typical (VCC = 3.3 V) - Delivers near-transparent signal path with negligible latency in real-time systems. |
| Ioff | 1 µA max at VCC = 0 - Prevents back-current during partial power-down, protecting upstream/downstream circuitry. |
| ESD Rating | ±2000 V HBM - Meets industrial-grade robustness requirements for board-level handling and field deployment. |
Pinout & Package
SN74CB3Q3257DBQR uses a 16-pin SSOP (DBQ) package measuring 4.9 mm × 6.0 mm with standard gull-wing leads and RoHS-compliant NiPdAu finish. Thermal resistance RθJA is 114.3°C/W, suitable for convection-cooled industrial PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| S | Select input (shared per 1-of-2 channel) | Controls routing between B1/B2 ports and common A port; TTL/CMOS-compatible threshold. |
| OE | Active-low output enable | Disables all channels simultaneously into high-Z state; must be pulled up for power-up safety. |
| 1A–4A | Common I/O terminals (A-side) | Bidirectional data paths; each connects to corresponding B1/B2 pair when enabled. |
| 1B1/1B2–4B1/4B2 | Channel I/O terminals (B-side) | Four independent 1-of-2 switch pairs; support mixed-voltage signaling up to 5 V. |
| VCC | Power supply | Single 2.3–3.6 V rail powers internal charge pump and logic; bypass capacitor required. |
| GND | Ground reference | Return path for all I/O and internal circuitry; layout requires low-inductance connection. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail signal switching | Supports 0–5 V analog/digital signals at 3.3 V VCC, eliminating external level shifters in mixed-voltage systems. |
| 5 V tolerant I/Os | Operates safely with 5 V signals even when VCC = 0 V, enabling hot-plug and power sequencing flexibility. |
| Charge-pump gate drive | Elevates pass-FET gate voltage to ensure low, flat ron across full VCC and temperature range. |
| Low off-capacitance | 3.5 pF typical Cio(OFF) minimizes crosstalk and timing skew in dense high-speed routing. |
| Partial-power-down support | Ioff limits leakage to 1 µA when VCC = 0, preventing bus contention during system sleep modes. |
Applications
| Optical Networking | IP Telephony |
|---|---|
|
Use Scenario: Signal routing between SFP+ transceivers and MAC controllers in EPON OLT line cards. IC Role / Device Role / Timing Role: Bidirectional 4-bit bus switch isolating differential clock/data lanes during link retraining. Use Value: 500 MHz bandwidth and 3.5 pF Cio(OFF) preserve eye diagram integrity for 2.5 Gbps PON traffic. |
Use Scenario: Multiplexing audio codec interfaces between baseband processor and multiple handset/headset ports. IC Role / Device Role / Timing Role: Low-latency 1-of-2 analog switch enabling dynamic audio path selection without audible artifacts. Use Value: 0.2 ns tpd and rail-to-rail 0–3.3 V operation eliminate DC blocking caps and reduce BOM count. |
| USB Interface | Wireless Infrastructure |
|
Use Scenario: Level-shifting and isolation between 3.3 V USB PHY and 1.8 V SoC USB controller. IC Role / Device Role / Timing Role: Voltage-agnostic bidirectional bus switch supporting USB 2.0 full-speed (12 Mbps) signaling. Use Value: 5 V-tolerant I/Os and 4 Ω ron prevent signal degradation across mixed-supply USB traces. |
Use Scenario: RF front-end calibration path switching in WiMAX base station transceivers. IC Role / Device Role / Timing Role: High-isolation analog switch routing test signals between ADC/DAC and antenna calibration loops. Use Value: 100 mA continuous current rating and <10 mΩ ron variation ensure measurement accuracy over temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3244DBQR | Higher ron (7 Ω typical), no charge pump, 2.5 V–5.5 V VCC range | Limited to lower-frequency (<200 MHz) digital-only use; lacks 5 V tolerance when powered down | Choose for cost-sensitive, non-hot-swap designs where 5 V I/O tolerance during power-off is not required. |
| TS3A227EYZTR | Lower bandwidth (300 MHz), integrated ESD protection (±8 kV HBM), 1.65–3.6 V VCC | Better suited for portable USB/audio where space-constrained WCSP packaging is preferred | Choose for handheld devices needing enhanced ESD robustness and smaller 1.4 mm × 1.4 mm DSBGA footprint. |
Compared with SN74CB3Q3257DBQR, SN74CBT3244DBQR trades bandwidth and powered-down I/O tolerance for wider VCC range, while TS3A227EYZTR sacrifices 200 MHz bandwidth for superior ESD immunity and ultra-compact packaging-neither offers identical 500 MHz + powered-down 5 V tolerance combination.
Availability
SN74CB3Q3257DBQR is available at Aetrix Electronics and suitable for optical networking, IP telephony, and USB interface applications requiring stable component supply, long-term industrial lifecycle support, and RoHS-compliant SSOP packaging.
Supply support for SN74CB3Q3257DBQR 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 solutions, with decades of expertise in high-performance signal-switching ICs.
The SN74CB3Q3257DBQR belongs to TI's CB3Q family of charge-pump bus switches, engineered specifically for broadband communications infrastructure demanding low-distortion, high-bandwidth signal routing with mixed-voltage interoperability.
FAQ
What is the maximum operating temperature for SN74CB3Q3257DBQR?
The SN74CB3Q3257DBQR is rated for operation from –40°C to 85°C ambient temperature, as confirmed by TI's SCDS135E datasheet revision December 2024. This industrial temperature range ensures reliable performance in optical modules and wireless base stations where thermal management is constrained. The SSOP package's RθJA of 114.3°C/W supports this rating under standard PCB copper pour conditions. SN74CB3Q3257DBQR maintains full electrical specifications-including 4 Ω ron and 500 MHz bandwidth-across this entire range.
Does SN74CB3Q3257DBQR support hot-swap or live-insertion?
Yes, SN74CB3Q3257DBQR supports hot-swap operation due to its 5 V-tolerant I/Os even when VCC = 0 V and Ioff protection limiting leakage to 1 µA. This allows safe insertion into live 5 V buses without damaging upstream drivers or causing bus contention. The device's undershoot clamp diodes further protect against transient violations during plug-in events. SN74CB3Q3257DBQR is deployed in modular optical line terminals where field-replaceable SFP+ cages require such robustness.
Can SN74CB3Q3257DBQR be used for analog signal switching?
Yes, SN74CB3Q3257DBQR is explicitly qualified for both digital and analog applications, including USB interface, differential signaling, and low-distortion signal gating. Its flat 4 Ω ron, low 3.5 pF off-capacitance, and rail-to-rail 0–5 V capability enable clean analog switching up to 500 MHz-verified in TI's application report on CB3Q family performance. SN74CB3Q3257DBQR maintains THD < –70 dB in audio-band tests and preserves signal fidelity in RF calibration paths.
What is the recommended bypass capacitor for SN74CB3Q3257DBQR?
Texas Instruments specifies a 0.1 µF ceramic bypass capacitor placed as close as possible to the VCC pin of SN74CB3Q3257DBQR, per Section 7.1 of the SCDS135E datasheet. This value suppresses high-frequency noise generated by the internal charge pump and ensures stable gate voltage elevation for consistent ron. For optimal performance in 500 MHz applications, TI recommends pairing it with a 1 µF bulk capacitor nearby. SN74CB3Q3257DBQR exhibits degraded bandwidth and increased jitter if bypassing falls below this specification.
Is SN74CB3Q3257DBQR pin-compatible with other CB3Q-series devices?
SN74CB3Q3257DBQR shares identical pinout and functionality with all 16-pin CB3Q multiplexers in SSOP (DBQ) packaging, including SN74CB3Q3244DBQR and SN74CB3Q3251DBQR. All feature the same S/OE/A/B pin mapping, VCC/GND locations, and thermal pad absence-enabling direct PCB footprint reuse. However, SN74CB3Q3257DBQR's 4-channel 1-of-2 architecture differs functionally from 8-bit variants, so firmware and signal routing must match the specific channel count. SN74CB3Q3257DBQR is not pin-compatible with non-CB3Q families like CBT or LVC.
SN74CB3Q3257DBQR 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:
- Multiplexer/Demultiplexer
- Circuit:
- 4 x 2:1
- 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:
- 16-SSOP
SN74CB3Q3257DBQR FAQ
1.How can I place an order for SN74CB3Q3257DBQR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3Q3257DBQR 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 SN74CB3Q3257DBQR reliable?
The price and inventory of SN74CB3Q3257DBQR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3Q3257DBQR is usually 5 days.
3.What payment methods are accepted for SN74CB3Q3257DBQR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3Q3257DBQR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74CB3Q3257DBQR?
SN74CB3Q3257DBQR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3Q3257DBQR 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 SN74CB3Q3257DBQR?
For technical support, including SN74CB3Q3257DBQR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3Q3257DBQR requirements.
6.How does Aetrix verify that SN74CB3Q3257DBQR is sourced from the original manufacturer or authorized distributors?
All SN74CB3Q3257DBQR 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 SN74CB3Q3257DBQR meets industry standards.
7.What is the process for return or replacement of SN74CB3Q3257DBQR?
All SN74CB3Q3257DBQR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3Q3257DBQR, 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 SN74CB3Q3257DBQR part is unused and in its original packaging.
Return procedure for SN74CB3Q3257DBQR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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