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Texas Instruments SN74CB3Q3245PW
- Part No.:
- SN74CB3Q3245PW
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CB3Q3245PW.pdf
- Description:
- IC BUS SWITCH 8 X 1:1 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,301
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Product details
Overview
SN74CB3Q3245PW from Texas Instruments is an 8-bit FET bus switch optimized for high-bandwidth, low-voltage applications. It supports rail-to-rail switching (0–5 V) with 2.5-V/3.3-V supply operation, features 4 Ω typical ON-state resistance (ron), 3.5 pF typical OFF-state I/O capacitance (Cio(OFF)), and bidirectional data flow with <0.2 ns propagation delay. It is used in PCI interface isolation and memory interleaving systems requiring minimal signal distortion.
For engineers reviewing the SN74CB3Q3245PW datasheet, SN74CB3Q3245PW pinout, SN74CB3Q3245PW application, or SN74CB3Q3245PW equivalent, key selection criteria include its 5-V tolerant I/Os, partial-power-down support via Ioff, 20 MHz maximum OE switching frequency, and TSSOP-20 (PW) package compatibility with high-density PCB layouts.
Technical Context
The SN74CB3Q3245PW implements a charge-pump-enhanced FET architecture to elevate gate voltage and maintain flat, low ON-state resistance across input voltage ranges - enabling rail-to-rail analog/digital signal switching without level translation. Its internal enable logic drives all eight switches synchronously via a single OE input.
It supports true bidirectional operation with near-zero propagation delay, leverages undershoot clamp diodes on data/control inputs, and incorporates Ioff circuitry to block reverse current during partial power-down - ensuring system-level isolation when VCC = 0 V while I/Os remain at 0–5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3 V to 3.6 V - enables interoperability with both 2.5-V and 3.3-V logic domains without external level shifters. |
| ron (Typ) | 4 Ω - ensures minimal voltage drop and signal attenuation across A/B ports under 30 mA load, critical for high-fidelity bus signaling. |
| Cio(OFF) (Typ) | 3.5 pF - reduces capacitive loading on driven buses, preserving signal integrity and timing margins in >200 MHz applications. |
| fOE (Max) | 20 MHz - defines maximum toggle rate of OE control input, limiting usable switching frequency in burst-mode or clock-gated configurations. |
| tpd (Max) | 0.20 ns - measured as RC time constant of ron and 50 pF load; enables sub-nanosecond latency in high-speed data gating paths. |
| Ioff (Max) | 1 µA at VCC = 0 V - guarantees safe isolation between powered and unpowered subsystems, preventing backfeed damage in hot-swap designs. |
| VI/O Range | 0 to 5.5 V - allows direct interfacing with 0.8-V, 1.2-V, 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V logic families regardless of VCC state. |
Pinout & Package
TSSOP-20 (PW) package: 6.5 mm × 4.4 mm, 1.2 mm max height, 0.65 mm pitch, exposed thermal pad not present (unlike RGY), lead-free NiPdAu finish, MSL Level-1 (260°C reflow unlimited).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19, 20 | NC | No internal connection - must be left floating or grounded per layout best practice; no electrical function. |
| 2–9 | A1–A8 | Input/output port A - bidirectional data path; electrically identical to B-side when switch is enabled. |
| 10 | GND | Ground reference - primary return path for VCC and all I/O currents; requires low-impedance PCB plane connection. |
| 11 | VCC | Supply voltage input - powers internal charge pump and switch control logic; bypass capacitor (0.1 µF) required adjacent to pin. |
| 12 | OE | Output-enable control - active-low; drives all 8 switches simultaneously; TTL/CMOS compatible with VIL ≤ 0.8 V (VCC = 3.6 V). |
| 13–20 | B1–B8 | Input/output port B - mirror of A-side; supports full bidirectional signal routing with no direction pin required. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail analog/digital switching | Supports 0–5 V signals with 2.5-V or 3.3-V VCC - eliminates need for external level translators in mixed-voltage systems. |
| Charge-pump gate drive | Elevates pass-transistor gate voltage above VCC - maintains flat ron across entire VI/O range, minimizing distortion in AC-coupled paths. |
| 5-V tolerant I/Os (powered up/down) | Withstands 0–5.5 V on A/B pins even when VCC = 0 V - enables safe hot-plug operation and legacy bus interfacing. |
| Low Cio(OFF) and Cio(ON) | 3.5 pF OFF / 10 pF ON - minimizes signal reflection, crosstalk, and timing skew in parallel bus and differential pair applications. |
| Ioff partial-power-down protection | Blocks reverse current flow into VCC when device is unpowered - prevents backfeeding and latch-up in multi-rail systems. |
Applications
| PCI Express Lane Isolation | Differential Signal Routing |
|---|---|
Use Scenario: Isolating PCIe Gen1/Gen2 lanes during system reset or firmware update to prevent bus contention. IC Role / Device Role / Timing Role: Bidirectional bus switch enabling/disabling physical layer connectivity without interrupting link training sequence timing. Use Value: Maintains signal fidelity with <0.2 ns tpd and 3.5 pF Cio(OFF), avoiding jitter accumulation that would trigger link retraining. |
Use Scenario: Gating LVDS or RSDS differential pairs in display interface multiplexing (e.g., dual-panel laptop displays). IC Role / Device Role / Timing Role: Low-capacitance, matched-path switch preserving common-mode rejection and skew budget across both legs. Use Value: 4 Ω ron and <100 mΩ channel matching ensure <1 ps inter-pair skew, meeting DisplayPort 1.2 eye diagram requirements. |
| Memory Interleaving Control | Legacy Bus Level Translation |
Use Scenario: Dynamically routing address/data lines between two DDR2 memory banks controlled by separate memory controllers. IC Role / Device Role / Timing Role: High-bandwidth 8-bit switch enabling bank-selective access with sub-nanosecond latency. Use Value: Flat ron over 0–3.3 V range prevents duty-cycle distortion on strobes and DQS signals, preserving setup/hold timing margins. |
Use Scenario: Interfacing 5-V industrial sensors to a 3.3-V microcontroller ADC input while maintaining signal integrity. IC Role / Device Role / Timing Role: Voltage-agnostic analog switch providing galvanic isolation and level adaptation without active buffering. Use Value: 0–5.5 V VI/O range and 3.5 pF Cio(OFF) allow direct connection with <1% gain error and no added noise floor degradation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDTQS3VH384 | Identical functional specification per TI documentation; same ron (4 Ω), Cio(OFF) (3.5 pF), and VCC range (2.3–3.6 V); pinout matches SN74CB3Q3245PW exactly. | Same use cases: PCI isolation, memory interleaving, hot-swap I/O gating - validated in IDT reference designs for telecom backplanes. | Select IDTQS3VH384 only if sourcing from IDT-authorized channels; verify top-side marking "QS3VH384" and RoHS compliance status per batch. |
| SN74CBTD3384PW | Higher ICC (5 mA typ vs. 1 mA), no charge pump → ron rises to 7 Ω at low VI/O; lacks Ioff protection; VCC min = 4.5 V - incompatible with 2.5-V operation. | Restricted to 5-V-only systems; unsuitable for partial-power-down or mixed-voltage interfaces where SN74CB3Q3245PW excels. | Choose SN74CBTD3384PW only for legacy 5-V backplane designs requiring higher drive strength; avoid in new 2.5/3.3-V designs. |
Compared with IDTQS3VH384, SN74CB3Q3245PW offers identical performance and pinout but broader supply chain availability; versus SN74CBTD3384PW, it delivers superior low-voltage operation, lower power, and robust power-down safety - making it the preferred choice for modern embedded and computing platforms.
Availability
SN74CB3Q3245PW is available at Aetrix Electronics and suitable for PCI interface isolation, memory interleaving, differential signal routing, and legacy bus level translation requiring stable component supply across industrial and computing OEM programs.
Supply support for SN74CB3Q3245PW 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 digital signal technologies, with over 50 years of innovation in high-reliability IC design.
The SN74CB3Q3245PW belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for broadband communications, networking infrastructure, and data-intensive computing systems demanding ultra-low distortion and rail-to-rail signal integrity.
FAQ
What is the maximum operating temperature range for the SN74CB3Q3245PW?
The SN74CB3Q3245PW is specified for operation from –40°C to +85°C ambient temperature. This range is validated per JEDEC JESD78 latch-up testing and JESD22 ESD stress protocols, ensuring reliable performance in industrial and commercial environments. Thermal impedance (θJA) is 83°C/W for the PW package, requiring appropriate PCB copper area for sustained 1 mA ICC operation at maximum temperature.
Does the SN74CB3Q3245PW support hot-swap operation when VCC is unpowered?
Yes, the SN74CB3Q3245PW supports hot-swap operation with VCC = 0 V due to its 5-V tolerant I/Os and Ioff circuitry. When unpowered, it blocks reverse current up to ±5.5 V on A/B pins with leakage <1 µA, preventing backfeed into other rails. OE must be held high (via pullup) to maintain high-impedance state during insertion - confirmed in TI application report SCBA004.
Can the SN74CB3Q3245PW be used for analog signal switching, such as audio or sensor signals?
Yes, the SN74CB3Q3245PW is qualified for analog signal switching including audio and sensor interfaces. Its rail-to-rail capability (0–5.5 V), low 4 Ω ron, and flat resistance profile minimize THD and signal compression. Measured Cio(OFF) = 3.5 pF and Cio(ON) = 10 pF ensure minimal capacitive loading on source impedances <1 kΩ, supporting bandwidths up to 500 MHz per TI characterization.
What is the recommended bypass capacitor value for the VCC pin of the SN74CB3Q3245PW?
Texas Instruments recommends a 0.1 µF ceramic bypass capacitor placed as close as possible to the VCC pin (Pin 11) and GND (Pin 10) of the SN74CB3Q3245PW. This value is validated for stable charge-pump operation and noise suppression across 2.3–3.6 V VCC and 20 MHz OE toggling. For systems with high di/dt transients, a parallel 1–10 µF tantalum or polymer capacitor may be added on the same net.
Is the SN74CB3Q3245PW pin-compatible with other packages in the CB3Q family, such as RGY or DBQ?
Yes, the SN74CB3Q3245PW shares identical pinout and functionality with SN74CB3Q3245RGYR (VQFN-20) and SN74CB3Q3245DBQR (SSOP-20), as confirmed in TI's SCDS124B datasheet Figure 1 and PACKAGE OUTLINE documents. All three use the same 20-pin assignment: A1–A8 (Pins 2–9), GND (10), VCC (11), OE (12), B1–B8 (13–20), plus NC (1, 19, 20). Mechanical dimensions differ, but PCB footprint is not interchangeable.
SN74CB3Q3245PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- Bus Switch
- Circuit:
- 8 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:
- 20-TSSOP
SN74CB3Q3245PW FAQ
1.How can I place an order for SN74CB3Q3245PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3Q3245PW 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 SN74CB3Q3245PW reliable?
The price and inventory of SN74CB3Q3245PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3Q3245PW is usually 5 days.
3.What payment methods are accepted for SN74CB3Q3245PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3Q3245PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74CB3Q3245PW?
SN74CB3Q3245PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3Q3245PW 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 SN74CB3Q3245PW?
For technical support, including SN74CB3Q3245PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3Q3245PW requirements.
6.How does Aetrix verify that SN74CB3Q3245PW is sourced from the original manufacturer or authorized distributors?
All SN74CB3Q3245PW 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 SN74CB3Q3245PW meets industry standards.
7.What is the process for return or replacement of SN74CB3Q3245PW?
All SN74CB3Q3245PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3Q3245PW, 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 SN74CB3Q3245PW part is unused and in its original packaging.
Return procedure for SN74CB3Q3245PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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