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Texas Instruments SN74CBT16861DL
- Part No.:
- SN74CBT16861DL
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 48-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
SN74CBT16861DL.pdf
- Description:
- IC BUS SWITCH 10 X 1:1 48SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,743
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Product details
Overview
SN74CBT16861DL from Texas Instruments is a 20-bit FET bus switch in SSOP-48 package, featuring 5-Ω on-state resistance, TTL-compatible inputs, and dual 10-bit independent switching channels controlled by separate OE pins. It enables low-propagation-delay bidirectional signal routing in high-speed digital backplanes and memory expansion interfaces.
For engineers reviewing the SN74CBT16861DL datasheet, SN74CBT16861DL pinout, SN74CBT16861DL application, or SN74CBT16861DL equivalent, key selection criteria include on-resistance matching across A/B ports, OE-controlled isolation timing (ten ≤ 6.5 ns, tdis ≤ 8 ns), thermal performance (θJA = 63°C/W), and compatibility with 4 V–5.5 V supply systems requiring latch-up immunity >100 mA per JESD 78 Class II.
Technical Context
The SN74CBT16861DL implements two independent 10-bit FET-based analog switches, each with dedicated OE control enabling simultaneous or staggered channel enablement. Its architecture provides true bidirectional signal flow with no internal directionality-signal integrity depends solely on external voltage biasing of A and B ports.
Each switch exhibits flat on-resistance (5 Ω typical at VCC = 4.5 V, II = 30 mA) and minimal charge injection (<0.5 pC), supporting clean TTL-level signal pass-through without level translation. Input clamp current rating (–50 mA) and absolute max VI range (–0.5 V to 7 V) allow robust handling of undershoot/overshoot transients in hot-swap environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5 Ω typical - ensures <0.32 V drop at 64 mA, preserving TTL logic margins across full 20-bit bus |
| Propagation delay (tpd) | 0.25 ns at VCC = 5 V - supports >1 GHz signal bandwidth with sub-nanosecond edge fidelity |
| Enable time (ten) | 1.7 ns min / 6.5 ns max - defines minimum OE assertion-to-output-valid window for synchronous bus gating |
| Disable time (tdis) | 1.5 ns min / 8 ns max - determines maximum hold time before output enters high-Z, critical for bus contention avoidance |
| Supply voltage range | 4 V to 5.5 V - matches standard 5-V TTL and mixed-voltage I/O domains without external regulation |
| Input leakage (II) | ±1 µA max - prevents unintended biasing of floating bus segments during disable state |
| Thermal resistance (θJA) | 63°C/W (SSOP-DL) - enables sustained 128 mA channel current at TA = 85°C with <40°C junction rise |
Pinout & Package
SN74CBT16861DL uses a 48-pin SSOP (DL) package with 0.5-mm pitch, 12.4 mm × 6.1 mm body size, and 1.2-mm max height per JEDEC MO-153. Pin 1 is located at top-left corner with quadrants Q1 orientation in tape.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A1–1A10, 2A1–2A10 | Port A inputs/outputs (Channel Group 1 & 2) | Bidirectional signal terminals for first and second 10-bit data paths; electrically identical, no internal direction logic |
| 1B1–1B10, 2B1–2B10 | Port B inputs/outputs (Channel Group 1 & 2) | Paired counterparts to A-side pins; connection path determined solely by OE state, not pin function |
| 1OE, 2OE | Output-enable controls (active-low) | Independent gating signals: low = connect A↔B; high = high-Z isolation between respective 10-bit groups |
| VCC (Pins 22, 36) | Power supply | Dual VCC pins reduce IR drop and improve noise rejection across wide 20-bit layout; must be decoupled locally |
| GND (Pins 12, 25) | Ground reference | Dual ground pins provide low-inductance return paths for both switch banks, minimizing crosstalk between groups |
| NC (Pins 1, 48) | No internal connection | Unbonded pads; must remain unconnected-no routing or thermal relief required |
Key Features
| Feature | Design Value |
|---|---|
| 5-Ω low on-resistance | Minimizes voltage drop and timing skew across all 20 bits, enabling clean TTL-level signal pass-through up to 100 MHz |
| TTL-compatible input thresholds | VIH = 2 V / VIL = 0.8 V ensures direct interfacing with legacy 5-V microcontrollers and ASICs without level shifters |
| Latch-up immunity >100 mA | Meets JESD 78 Class II, allowing safe operation in noisy industrial backplanes with transient coupling |
| Independent dual OE control | Enables selective activation of 10-bit subsets-e.g., isolate memory address vs. data bus segments independently |
| High-speed switching (tpd = 0.25 ns) | Supports sub-nanosecond edge rates required for DDR memory bus isolation and test access port (TAP) multiplexing |
Applications
| Memory Expansion Interface | PCI/ISA Bus Isolation |
|---|---|
|
Use Scenario: Adding secondary SRAM or Flash memory to a microcontroller with limited address/data pins. IC Role / Device Role / Timing Role: Bidirectional 20-bit bus switch that routes shared address/data lines between MCU and expansion memory under OE control. Use Value: Eliminates need for discrete transceivers or CPLDs; 5-Ω ron preserves setup/hold timing margins at 50-MHz bus speeds. |
Use Scenario: Isolating legacy ISA peripherals from a PCI host bridge during hot-plug events. IC Role / Device Role / Timing Role: High-speed gate controlling bidirectional data flow between PCI and ISA domains, activated only during transaction windows. Use Value: Prevents bus contention during reset or configuration; 6.5 ns ten ensures OE assertion aligns with PCI FRAME# deassertion timing. |
| Test Access Multiplexer | Digital Logic Analyzer Probe Interface |
|
Use Scenario: Sharing JTAG TDI/TDO/TMS/TCK lines among multiple ASICs on a board using boundary scan. IC Role / Device Role / Timing Role: Low-capacitance (5.5 pF Cio(OFF)) analog switch selecting one device's TAP signals onto shared debug bus. Use Value: Maintains signal integrity for 10-MHz+ JTAG clocks; <0.35 ns tpd avoids skew-induced protocol errors. |
Use Scenario: Connecting 20-channel logic analyzer pods to various digital subsystems without permanent soldering. IC Role / Device Role / Timing Role: Reconfigurable signal path selector routing probe points to analyzer inputs under software-controlled OE. Use Value: Enables non-invasive debugging of high-speed buses; 128 mA channel rating supports driving 50-Ω terminated analyzer inputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD16210DLR | 24-bit, 3-state outputs with 3.3-V-only supply (3.0–3.6 V); higher ron (7 Ω typ); no dual OE | Targeted at 3.3-V LVTTL systems; lacks independent group control needed for segmented bus gating | Select when operating exclusively at 3.3 V and full 24-bit width is required; avoid if 5-V compatibility or dual-OE flexibility is needed. |
| SN74CB3Q3257PWR | 4-channel 2:1 multiplexer (8-bit total); 3.3-V supply only; integrated level-shifting; lower capacitance (3 pF) | Optimized for point-to-point signal routing rather than wide-bus switching; no high-current drive capability | Prefer for low-capacitance, level-shifted signal selection in mixed-voltage FPGA I/O; unsuitable for 20-bit parallel bus isolation. |
Compared with SN74CBT16861DL, SN74CBTD16210DLR offers greater bit width but sacrifices 5-V operation and dual-OE control, while SN74CB3Q3257PWR provides superior signal fidelity at 3.3 V but cannot replicate the 20-bit, high-drive, independently gated architecture essential for backplane and memory expansion use cases.
Availability
SN74CBT16861DL is available at Aetrix Electronics and suitable for memory expansion interfaces, PCI/ISA bus isolation, JTAG test access multiplexing, and logic analyzer probe routing requiring stable component supply and long-term industrial lifecycle support.
Supply support for SN74CBT16861DL 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, power efficiency, and system integration.
The SN74CBT16861DL belongs to TI's Widebus™ family of high-speed bus switches, engineered specifically for low-latency, bidirectional signal routing in 5-V digital systems such as industrial controllers, telecom line cards, and test equipment.
FAQ
What is the maximum continuous current rating per channel for the SN74CBT16861DL?
The SN74CBT16861DL supports a continuous channel current of 128 mA per switch path, verified under recommended operating conditions (VCC = 4 V to 5.5 V, TA = –40°C to 85°C). This rating ensures reliable operation when driving terminated transmission lines or multiple TTL inputs without thermal derating in SSOP-DL package.
Does the SN74CBT16861DL require external pull-up or pull-down resistors on its OE pins?
No-SN74CBT16861DL OE inputs are TTL-compatible with defined VIH (≥2 V) and VIL (≤0.8 V) thresholds, and internal circuitry ensures proper logic interpretation without external biasing. However, TI recommends tying unused OE pins directly to VCC or GND per SCBA004 to prevent floating states that could cause partial conduction or increased ICC.
Can the SN74CBT16861DL operate with a 3.3-V supply voltage?
No-the SN74CBT16861DL has a minimum recommended VCC of 4 V per its datasheet; operation below 4 V violates recommended conditions and risks undefined switching behavior, elevated on-resistance (>15 Ω), and failure to meet timing specs (ten/tdis). For 3.3-V systems, consider SN74CB3Q3257PWR or SN74CBTD16210DLR instead.
How does the SN74CBT16861DL handle input voltage excursions beyond VCC or below GND?
The SN74CBT16861DL tolerates input voltages from –0.5 V to 7 V per absolute maximum ratings, with input clamp current rated at –50 mA for negative excursions. This allows safe operation during hot-swap events or signal overshoot/undershoot common in backplane environments, provided clamp current limits are observed to avoid damage.
Is the SN74CBT16861DL pin-compatible with other members of the Widebus™ CBT family?
SN74CBT16861DL shares the same 48-pin SSOP-DL footprint and pinout with SN74CBT16210DL and SN74CBT16212DL, but differs in internal grouping (dual 10-bit vs. single 20-bit or 12-bit + 8-bit). Direct replacement requires verification of OE mapping and functional partitioning-substitution may alter bus segmentation behavior in existing designs.
SN74CBT16861DL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 48-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Bus Switch
- Circuit:
- 10 x 1:1
- Independent Circuits:
- 2
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-SSOP
SN74CBT16861DL FAQ
1.How can I place an order for SN74CBT16861DL through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT16861DL 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 SN74CBT16861DL reliable?
The price and inventory of SN74CBT16861DL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT16861DL is usually 5 days.
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SN74CBT16861DL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT16861DL 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 SN74CBT16861DL?
For technical support, including SN74CBT16861DL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT16861DL requirements.
6.How does Aetrix verify that SN74CBT16861DL is sourced from the original manufacturer or authorized distributors?
All SN74CBT16861DL 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 SN74CBT16861DL meets industry standards.
7.What is the process for return or replacement of SN74CBT16861DL?
All SN74CBT16861DL units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT16861DL, 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 SN74CBT16861DL part is unused and in its original packaging.
Return procedure for SN74CBT16861DL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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