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Texas Instruments SN74CB3Q3257PWG4
- Part No.:
- SN74CB3Q3257PWG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CB3Q3257PWG4.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,118
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Product details
Overview
SN74CB3Q3257PWG4 from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer bus switch optimized for high-bandwidth signal routing. It delivers rail-to-rail switching (0–5V with 3.3V VCC), 4Ω typical on-state resistance, <0.32ns propagation delay at 3.3V, and 5V-tolerant I/Os during powered-up or powered-down states - enabling robust signal integrity in USB interface and optical networking applications.
For engineers reviewing the SN74CB3Q3257PWG4 datasheet, SN74CB3Q3257PWG4 pinout, SN74CB3Q3257PWG4 application, or SN74CB3Q3257PWG4 equivalent, key selection criteria include its 2.3–3.6V supply range, bidirectional low-distortion data flow, Ioff partial-power-down support, and TSSOP-16 package compatibility with high-density PCB layouts.
Technical Context
The SN74CB3Q3257PWG4 integrates four independent 1-of-2 analog/digital switches, each controlled by a dedicated select (S) input and shared output-enable (OE) pin. Its charge-pump gate drive elevates pass-transistor gate voltage to maintain flat ron across input voltage range, enabling consistent 500MHz bandwidth and minimal signal distortion.
Each channel supports bidirectional operation with near-zero propagation delay, 3.5pF typical OFF-state I/O capacitance, and undershoot clamp diodes on all control/data terminals. The device operates across –40°C to 105°C and meets JESD 78 Class II latch-up immunity (>100mA) and JESD 22 ESD ratings (2000V HBM, 1000V CDM).
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) | 4Ω at 2.5V/3.3V - ensures minimal voltage drop and signal attenuation in high-speed data paths |
| tpd (Max) | 0.32ns at VCC = 3.3V - supports sub-nanosecond timing budgets in DDR, USB, and serial link interfaces |
| Cio(OFF) | 3.5pF typical (B port) - reduces capacitive loading to preserve signal rise/fall times and impedance matching |
| fOE (Max) | 20MHz - defines maximum toggle rate for OE-controlled channel enable/disable sequencing |
| Ioff Support | Yes - prevents backflow current during partial power-down, critical for hot-swap and mixed-voltage system reliability |
| Operating Temp | –40°C to 105°C - qualified for industrial and telecom infrastructure environments |
Pinout & Package
TSSOP-16 (PW) package: 5mm × 6.4mm body, 0.65mm lead pitch, exposed thermal pad (not electrically connected), RoHS-compliant NiPdAu finish, MSL Level-1 (260°C reflow unlimited).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| S | Select input (global) | Controls path selection across all four channels: S=L routes A→B1; S=H routes A→B2 |
| OE | Output enable (active-low) | Disables all channels when high; enables bidirectional conduction when low |
| 1A–4A | Common I/O ports | Bidirectional data terminals for channel 1–4; connect to shared bus or controller |
| 1B1/1B2–4B1/4B2 | Channel I/O pairs | Two independent I/O paths per channel; B1/B2 are selectable destinations/sources |
| VCC | Power supply | Supplies internal charge pump and logic; must be bypassed with 0.1µF capacitor near pin |
| GND | Ground reference | Return path for all signals and internal circuitry; requires low-impedance PCB plane connection |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail analog switching | Supports 0–5V signal swing with 3.3V VCC - eliminates level-shifting in mixed-voltage USB 2.0 and PCIe Gen1 interconnects |
| 5V-tolerant I/Os | Operates safely with 5V signals regardless of VCC state (powered up/down) - simplifies hot-plug and legacy interface integration |
| Low and flat ron | 4Ω typical, <8Ω max over full voltage/temp range - maintains signal fidelity and minimizes insertion loss in RF/analog paths |
| Bidirectional zero-delay path | No internal logic or buffering - preserves edge integrity for clock distribution and differential signaling |
| Ioff partial-power-down | Isolates powered-down sections from live buses - prevents current leakage and system-level fault propagation |
Applications
| USB 2.0 Interface Switching | Optical Networking Signal Gating |
|---|---|
Use Scenario: Routing high-speed USB D+/D− signals between host controller and dual peripheral ports in IP phones or PBX systems. IC Role / Device Role / Timing Role: Bidirectional analog switch providing low-capacitance, low-ron path with no added propagation delay to preserve USB 2.0 eye diagram integrity. Use Value: Enables seamless port sharing without signal degradation, meeting USB 2.0 480Mbps timing margins and ESD robustness requirements. | Use Scenario: Isolating differential video-over-fiber or EPON control lines during module hot-swap or fault recovery sequences. IC Role / Device Role / Timing Role: High-bandwidth analog gate that maintains impedance continuity and minimizes reflections on 100Ω differential traces. Use Value: Prevents signal corruption during reconfiguration, supporting uninterrupted optical link operation and reducing bit-error-rate in 1.25Gbps links. |
| Industrial Bus Isolation | Differential Signal Multiplexing |
Use Scenario: Segregating CAN or RS-485 bus segments in factory automation controllers to prevent ground-loop interference and fault propagation. IC Role / Device Role / Timing Role: Low-leakage, high-isolation switch enabling galvanic separation while preserving signal amplitude and edge rate. Use Value: Achieves >10⁹Ω off-state isolation and <3.5pF capacitance - critical for noise immunity in noisy industrial environments. | Use Scenario: Multiplexing LVDS or RSDS clock/data pairs between FPGA I/O banks and multiple display or sensor interfaces in embedded vision systems. IC Role / Device Role / Timing Role: Matched-pair analog switch ensuring skew <10ps between differential legs and maintaining common-mode rejection. Use Value: Delivers sub-0.32ns tpd matching and <0.5Ω ron mismatch - preserves differential timing integrity for 100+MHz pixel clocks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3257PWR | Higher ron (7Ω typ), no charge pump, 2.5V–5.5V VCC range, lower bandwidth (≤200MHz) | Limited to lower-speed digital-only applications; lacks 5V-tolerance during power-down | Choose for cost-sensitive, non-hot-swap designs where 5V I/O tolerance and sub-ns timing are not required |
| TS3A226AEYFFR | Single-supply 1.65–3.6V operation, 0.7Ω ron, 300MHz bandwidth, no Ioff, smaller WCSP-16 package | Not suitable for mixed-voltage or hot-swap systems; lacks 5V I/O tolerance and industrial temp rating | Prefer for space-constrained portable devices needing ultra-low ron but operating only within 1.8V/3.3V domains |
Compared with SN74CBT3257PWR and TS3A226AEYFFR, the SN74CB3Q3257PWG4 uniquely combines 5V I/O tolerance during power-down, 4Ω ron, 500MHz bandwidth, and –40°C to 105°C qualification - making it the only option for robust, high-speed, mixed-voltage industrial and telecom switching.
Availability
SN74CB3Q3257PWG4 is available at Aetrix Electronics and suitable for USB interface design, optical networking equipment, industrial bus isolation, and differential signal multiplexing requiring stable component supply and long-term production continuity.
Supply support for SN74CB3Q3257PWG4 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-reliability components.
The SN74CB3Q3257 belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, rail-to-rail analog/digital signal routing in broadband communications, optical infrastructure, and industrial control systems.
FAQ
What is the maximum signal frequency supported by the SN74CB3Q3257PWG4?
The SN74CB3Q3257PWG4 supports up to 500MHz signal bandwidth due to its low 4Ω typical on-state resistance and 3.5pF OFF-state I/O capacitance. This performance is validated under 3.3V VCC operation with matched 50Ω source/load conditions and is suitable for USB 2.0, EPON, and LVDS applications where signal integrity is critical. Bandwidth may decrease with higher trace capacitance or mismatched impedances.
Does the SN74CB3Q3257PWG4 support hot-swap or partial-power-down operation?
Yes, the SN74CB3Q3257PWG4 includes Ioff circuitry that actively isolates I/O ports when VCC = 0V, preventing damaging current backflow during hot-swap or partial-power-down events. This feature is confirmed in Section 5.5 Electrical Characteristics (Ioff = 1µA max) and Section 6.4 Device Functional Modes, making SN74CB3Q3257PWG4 suitable for systems requiring live insertion/removal of modules.
Can the SN74CB3Q3257PWG4 operate with 2.5V and 3.3V supplies simultaneously?
No - the SN74CB3Q3257PWG4 has a single VCC pin and operates from one supply voltage between 2.3V and 3.6V. However, its 5V-tolerant I/Os allow interfacing with 2.5V, 3.3V, or 5V signal sources/sinks regardless of VCC level. For example, with VCC = 2.5V, it supports 0–3.3V signaling; with VCC = 3.3V, it supports 0–5V signaling - eliminating need for external level shifters.
What is the function of the S and OE pins on the SN74CB3Q3257PWG4?
The S (Select) pin determines which B-port (B1 or B2) connects to the A-port for each of the four channels: S = low selects B1, S = high selects B2. The OE (Output Enable) pin is active-low and globally enables or disables all channels - when OE = low, selected paths conduct bidirectionally; when OE = high, all A–B paths enter high-impedance state. Both pins accept TTL/CMOS-compatible logic levels per Section 5.3 Recommended Operating Conditions.
Is the SN74CB3Q3257PWG4 pin-compatible with other packages in the same family?
Yes - the SN74CB3Q3257PWG4 (TSSOP-16) shares identical pinout and functionality with SN74CB3Q3257DBQR (SSOP-16), SN74CB3Q3257DGVR (TVSOP-16), and SN74CB3Q3257RGYR (VQFN-16), as confirmed in Figure 4-1 and Table 4-1 of the datasheet. All variants use the same 16-pin assignment, allowing direct PCB footprint interchangeability where package height and thermal requirements permit.
SN74CB3Q3257PWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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-TSSOP
SN74CB3Q3257PWG4 FAQ
1.How can I place an order for SN74CB3Q3257PWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3Q3257PWG4 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 SN74CB3Q3257PWG4 reliable?
The price and inventory of SN74CB3Q3257PWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3Q3257PWG4 is usually 5 days.
3.What payment methods are accepted for SN74CB3Q3257PWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3Q3257PWG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74CB3Q3257PWG4?
SN74CB3Q3257PWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3Q3257PWG4 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 SN74CB3Q3257PWG4?
For technical support, including SN74CB3Q3257PWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3Q3257PWG4 requirements.
6.How does Aetrix verify that SN74CB3Q3257PWG4 is sourced from the original manufacturer or authorized distributors?
All SN74CB3Q3257PWG4 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 SN74CB3Q3257PWG4 meets industry standards.
7.What is the process for return or replacement of SN74CB3Q3257PWG4?
All SN74CB3Q3257PWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3Q3257PWG4, 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 SN74CB3Q3257PWG4 part is unused and in its original packaging.
Return procedure for SN74CB3Q3257PWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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