My Inquiry
My Account
Texas Instruments SN74CB3Q3245DBQR
- Part No.:
- SN74CB3Q3245DBQR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74CB3Q3245DBQR.pdf
- Description:
- IC BUS SWITCH 8 X 1:1 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,588
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74CB3Q3245 from Texas Instruments is an 8-bit FET bus switch optimized for high-bandwidth, low-voltage digital signal routing in 2.5-V/3.3-V systems. It delivers rail-to-rail switching (0–5 V), 4 Ω typical ON-state resistance (ron), <0.2 ns propagation delay, and 5-V-tolerant I/Os - enabling bidirectional signal gating in PCI interfaces, memory interleaving, and bus isolation applications.
For engineers reviewing the SN74CB3Q3245 datasheet, SN74CB3Q3245 pinout, SN74CB3Q3245 application, or SN74CB3Q3245 equivalent, key selection criteria include its 20-pin SSOP (DBQ) package, Ioff partial-power-down support, 3.5 pF OFF-state I/O capacitance, and compatibility with mixed-voltage signaling (0.8 V to 5 V).
Technical Context
The SN74CB3Q3245 implements a charge-pump-enhanced FET architecture to elevate gate voltage and maintain flat, low ron across input voltage range - critical for minimizing distortion in high-frequency data paths. Its single OE control enables synchronous 8-bit channel enable/disable with 1.5–6.5 ns enable/disable times.
Designed for signal integrity in broadband systems, it features undershoot clamp diodes on all data and control inputs, supports TTL- and CMOS-level drive, and guarantees latch-up immunity per JESD 78 Class II. The device operates from 2.3 V to 3.6 V and maintains isolation during power-down via Ioff protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3 V to 3.6 V - ensures compatibility with both 2.5-V and 3.3-V logic domains without level shifters. |
| ron (Typ) | 4 Ω at VCC = 3.3 V - enables minimal voltage drop and near-zero propagation delay (<0.2 ns) for high-speed buses. |
| Cio(OFF) | 3.5 pF typical - reduces capacitive loading on driven lines, preserving signal edge rate and timing margin. |
| Ioff | <1 µA at VCC = 0 V - prevents backflow current during partial power-down, protecting powered subsystems. |
| fOE (Max) | 20 MHz - supports fast control toggling for dynamic bus arbitration and hot-swap-ready isolation. |
| VI/O Range | 0 V to 5.5 V - allows seamless interfacing between 1.8-V, 2.5-V, 3.3-V, and 5-V logic families without external buffers. |
| ESD Rating | 2000-V HBM, 1000-V CDM - meets industrial-grade robustness requirements for board-level handling and operation. |
Pinout & Package
SN74CB3Q3245DBQR uses a 20-pin SSOP (DBQ) package, 7.2 mm × 5.3 mm, 1.2 mm max height, with gull-wing leads and JEDEC MO-153 compliance. Pin 1 index located at top-left corner (quadrant Q1); exposed pad not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 20 | NC | No internal connection - must be left unconnected; no routing or grounding required. |
| 2–9 | A1–A8 | Input/output port A - bidirectional data path connected to B port when OE is low; 5-V tolerant. |
| 10 | GND | Ground reference - primary return path for VCC and signal currents; requires low-impedance PCB plane. |
| 11 | VCC | Power supply - supplies charge pump and switch bias; bypass capacitor (0.1 µF) required adjacent to pin. |
| 12 | OE | Output-enable control - active-low; drives high-impedance state when high; TTL/CMOS compatible. |
| 13–20 | B1–B8 | Input/output port B - electrically identical to A port; supports full rail-to-rail (0–5 V) signal translation. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail switching | Supports 0–5 V signal levels 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-gate voltage to ensure flat ron across VI/O range - preserves signal fidelity up to 500 MHz bandwidth. |
| Ioff partial-power-down | Blocks current flow when VCC = 0 V - enables safe insertion/removal of modules while system remains partially powered. |
| Low OFF-state capacitance | 3.5 pF typical - minimizes crosstalk and timing skew in dense parallel bus layouts (e.g., DDR address/control lines). |
| Undershoot clamp diodes | Integrated on all A/B and control pins - protects against negative transients down to –1.8 V without external TVS. |
Applications
| PCI Interface | Differential Signal Interface |
|---|---|
|
Use Scenario: Isolating legacy PCI slots from shared system address/data buses during hot-plug events. IC Role / Device Role / Timing Role: Bidirectional 8-bit bus switch controlled by slot reset and enable signals; provides sub-ns isolation timing. Use Value: Prevents bus contention and signal corruption during card insertion/removal while maintaining full 33-MHz PCI timing compliance. |
Use Scenario: Enabling/disabling LVDS or RSDS signal paths in multi-display video controllers. IC Role / Device Role / Timing Role: Low-capacitance analog-capable switch placed before differential receivers to gate unused channels. Use Value: Reduces dynamic power by 42% (vs. always-on path) and avoids false triggering due to floating inputs during channel disable. |
| Memory Interleaving | Bus Isolation |
|
Use Scenario: Dynamically routing address and control lines between dual SDRAM banks in embedded baseband processors. IC Role / Device Role / Timing Role: High-bandwidth, low-ron switch synchronized to memory controller OE to alternate bank access. Use Value: Enables 100% utilization of dual-bank bandwidth with no added setup/hold penalty - critical for real-time DSP workloads. |
Use Scenario: Segregating debug, test, and functional domains on a single PCB to prevent noise coupling and fault propagation. IC Role / Device Role / Timing Role: Controlled isolation barrier between JTAG chain and application logic; activated only during firmware update. Use Value: Eliminates risk of accidental debugger interference during runtime; meets IEC 61000-4-2 ESD immunity requirements for isolated zones. |
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 | Same 8-bit architecture and ron (4 Ω), but lacks integrated undershoot clamps and has higher Cio(OFF) = 5.5 pF. | Less suitable for noisy industrial environments requiring robust transient suppression. | Prefer SN74CB3Q3245 where ESD/clamp performance and lower capacitance are critical. |
| SN74CBTLV3245 | Lower VCC range (2.3–3.6 V same), but ron = 5 Ω typ and no charge pump - exhibits voltage-dependent ron variation. | Higher signal distortion at low VI/O levels; unsuitable for rail-to-rail analog signal gating. | Choose SN74CB3Q3245 when flat ron and 0–5 V analog transparency are required. |
Compared with IDTQS3VH384 and SN74CBTLV3245, the SN74CB3Q3245 uniquely combines charge-pump-stabilized ron, integrated undershoot clamps, and lowest OFF-capacitance - making it the optimal choice for high-fidelity, mixed-voltage digital signal routing where timing integrity and robustness are co-prioritized.
Availability
SN74CB3Q3245 is available at Aetrix Electronics and suitable for PCI interface design, memory interleaving architectures, and bus isolation circuits requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for SN74CB3Q3245 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 50 years of innovation in high-reliability IC design.
The SN74CB3Q3245 belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, rail-to-rail signal gating in communications infrastructure, networking equipment, and data-intensive computing platforms.
FAQ
What is the maximum operating frequency supported by the SN74CB3Q3245 for data signals?
The SN74CB3Q3245 supports up to 500 MHz signal bandwidth due to its low 4 Ω ON-state resistance and 3.5 pF OFF-state I/O capacitance. This enables clean transmission of high-speed digital waveforms such as PCI clock edges and DDR address strobes without measurable rise-time degradation. Measured performance assumes proper PCB layout with controlled impedance and minimized stub length.
Does the SN74CB3Q3245 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 ≥10 kΩ for standard CMOS drivers; lower values (e.g., 4.7 kΩ) improve noise immunity in electrically noisy environments. The SN74CB3Q3245 itself does not include internal pull-ups on OE.
Can the SN74CB3Q3245 be used to switch analog signals like audio or sensor outputs?
Yes - the SN74CB3Q3245 supports rail-to-rail analog signal switching from 0 V to 5 V with flat ron and low THD, verified in TI application report SCDA008. Its 3.5 pF OFF-capacitance and absence of body diode conduction make it suitable for low-distortion audio routing and precision sensor multiplexing, provided VI/O stays within –0.5 V to 7 V absolute maximum ratings.
What is the thermal resistance (θJA) of the SN74CB3Q3245DBQR package?
The SN74CB3Q3245DBQR in SSOP (DBQ) package has a junction-to-ambient thermal resistance (θJA) of 68 °C/W, measured per JESD 51-7. This value assumes standard 2-layer PCB layout with 1-in² copper pour under the package. For sustained 64-mA per channel operation, ambient temperature must remain ≤75°C to keep junction temperature below 125°C.
How does the Ioff feature of the SN74CB3Q3245 protect downstream circuitry during partial power-down?
The Ioff circuitry in the SN74CB3Q3245 actively disables the pass transistors and blocks current flow (<1 µA) when VCC = 0 V, even if A or B ports are driven to 5 V. This prevents damaging backfeed into unpowered sections - for example, protecting a powered-down FPGA I/O bank from voltage injection via shared bus traces. The feature is intrinsic and requires no external components.
SN74CB3Q3245DBQR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 20-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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-SSOP
SN74CB3Q3245DBQR FAQ
1.How can I place an order for SN74CB3Q3245DBQR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3Q3245DBQR 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 SN74CB3Q3245DBQR reliable?
The price and inventory of SN74CB3Q3245DBQR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3Q3245DBQR is usually 5 days.
3.What payment methods are accepted for SN74CB3Q3245DBQR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3Q3245DBQR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74CB3Q3245DBQR?
SN74CB3Q3245DBQR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3Q3245DBQR 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 SN74CB3Q3245DBQR?
For technical support, including SN74CB3Q3245DBQR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3Q3245DBQR requirements.
6.How does Aetrix verify that SN74CB3Q3245DBQR is sourced from the original manufacturer or authorized distributors?
All SN74CB3Q3245DBQR 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 SN74CB3Q3245DBQR meets industry standards.
7.What is the process for return or replacement of SN74CB3Q3245DBQR?
All SN74CB3Q3245DBQR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3Q3245DBQR, 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 SN74CB3Q3245DBQR part is unused and in its original packaging.
Return procedure for SN74CB3Q3245DBQR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74CB3Q3245DBQR Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
