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Texas Instruments TCA9517DR
- Part No.:
- TCA9517DR
- Manufacturer:
- Texas Instruments
- Category:
- Translators, Level Shifters
- Package:
- Datasheet:
-
TCA9517DR.pdf
- Description:
- IC TRANSLTR BIDIRECTIONAL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:19,940
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Product details
Overview
TCA9517DR from Texas Instruments is a bidirectional I²C/SMBus bus repeater with integrated level-shifting capability, enabling voltage translation between 0.9 V–5.5 V (A-side) and 2.7 V–5.5 V (B-side). It buffers both SDA and SCL lines, supports standard- and fast-mode I²C (up to 400 kHz), features active-high enable control, and maintains high-impedance I/Os when unpowered - used in server backplanes and industrial I²C expansion systems.
For engineers reviewing the TCA9517DR datasheet, TCA9517DR pinout, TCA9517DR application, or TCA9517DR equivalent, this page delivers verified electrical parameters, validated A/B-side supply domain behavior, confirmed open-drain I²C interface timing, and real-world design constraints for mixed-voltage I²C topologies including star and series repeater configurations.
Technical Context
The TCA9517DR implements asymmetric bidirectional buffering: A-side drivers operate from 0.9 V to 5.5 V with hard-ground low output (VOL ≤ 0.2 V at 6 mA) and 0.3×VCCA input threshold; B-side drivers operate from 2.7 V to 5.5 V with buffered-low output (~0.5 V) and require ≥70 mV below VOL to recognize a valid low. This prevents lockup when cascading B-side ports.
All I/Os are 5.5-V tolerant regardless of power state, and the EN pin is internally pulled up to VCCB. The device supports clock stretching but requires careful pull-up resistor sizing on the B-side to ensure VILC ≤ 0.4 V for reliable contention detection - critical for multi-master and long-trace I²C deployments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| A-side supply range | 0.9 V to 5.5 V - enables direct interface with ultra-low-voltage logic (e.g., 0.9 V I/O domains) |
| B-side supply range | 2.7 V to 5.5 V - compatible with standard 3.3 V/5 V I²C slaves and masters |
| Propagation delay (A→B) | 25–230 ns - determines maximum achievable I²C clock frequency in repeater chains |
| Propagation delay (B→A) | 80–250 ns - impacts acknowledge timing and clock stretching handoff integrity |
| VOL (A-side, 6 mA) | ≤ 0.2 V - ensures robust low-level recognition by sub-1 V logic receivers |
| VOL (B-side, 6 mA) | 0.45–0.6 V - defines buffered-low offset requiring VILC ≤ 0.4 V for valid low detection |
| Input capacitance (EN) | 6–10 pF - minimal loading on enable control line; supports clean digital switching |
Pinout & Package
Package: SOIC-8 (4.90 mm × 3.91 mm) - industry-standard footprint compatible with automated assembly and thermal management per RθJA = 133.6°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VCCA | A-side supply reference | Sets 0.3×VCCA input threshold; powers A-side comparators only - not main logic supply |
| 2 - SCLA | A-side serial clock I/O | Open-drain, 5.5-V tolerant; requires external pull-up to VCCA |
| 3 - SDAA | A-side serial data I/O | Open-drain, 5.5-V tolerant; requires external pull-up to VCCA |
| 4 - GND | Signal ground reference | Common return for all internal circuitry; must be low-impedance connection |
| 5 - EN | Active-high enable input | Internally pulled up to VCCB; must be asserted only during bus idle to prevent protocol corruption |
| 6 - SDAB | B-side serial data I/O | Open-drain, 5.5-V tolerant; requires external pull-up to VCCB |
| 7 - SCLB | B-side serial clock I/O | Open-drain, 5.5-V tolerant; requires external pull-up to VCCB |
| 8 - VCCB | Main supply and B-side reference | Powers internal logic, B-side drivers, and EN pull-up; defines VIL/VIH thresholds for B-side I/Os |
Key Features
| Feature | Design Value |
|---|---|
| Asymmetric A/B-side driver architecture | Prevents B-side-to-B-side connection lockup via buffered-low output (0.5 V) and strict VILC ≤ 0.4 V requirement |
| 5.5-V tolerant I/Os with zero-power operation | Enables hot-plug and partial-power-down scenarios without damaging connected devices or degrading signal integrity |
| Configurable bus segmentation | Supports star topology (multiple A-sides tied together) and series topology (A-to-B chaining) - no voltage offset accumulation |
| Standard- and fast-mode I²C compliance | Validated timing across –40°C to 85°C with 400-pF max bus capacitance per segment |
| Integrated power-good detection | Automatically disables outputs until VCCA > 0.8 V and VCCB > 2.5 V - eliminates glitching during power sequencing |
Applications
| Server Backplane Expansion | Industrial PLC I/O Module Interfacing |
|---|---|
Use Scenario: Extending I²C communication across multiple PCBs in a 19-inch rack-mounted server chassis where CPU board operates at 1.2 V and peripheral modules use 3.3 V I²C. IC Role / Device Role / Timing Role: Bidirectional repeater with level shifting - isolates bus segments, translates 1.2 V SDA/SCL to 3.3 V levels, and regenerates signals to maintain timing margins over 15 cm traces. Use Value: Enables reliable multi-drop I²C addressing and ACK/NACK handshaking across voltage domains without custom level-shifters or protocol-aware firmware intervention. |
Use Scenario: Connecting legacy 5 V I²C sensors and actuators to a modern 3.3 V microcontroller-based PLC mainboard in factory automation equipment. IC Role / Device Role / Timing Role: Voltage-level translator and bus buffer - absorbs capacitive loading from long wiring harnesses (>2 m), restores rise/fall times, and prevents bus lockup during hot-swap events. Use Value: Eliminates need for discrete MOSFET translators while supporting clock stretching required by slow-response analog sensor ICs. |
| Telecom Router Control Plane | Medical Diagnostic Equipment Subsystem Linking |
Use Scenario: Isolating I²C control buses between baseband processor (1.8 V I/O) and RF front-end modules (3.3 V I/O) in carrier-grade routers to reduce crosstalk and EMI. IC Role / Device Role / Timing Role: Active repeater with enable control - allows dynamic segmentation during firmware updates or fault recovery, blocking noise propagation between subsystems. Use Value: Provides deterministic bus isolation with <100 ns added latency, meeting telecom control-plane jitter budgets under full load. |
Use Scenario: Interfacing low-power 0.9 V biomedical sensor ASICs (e.g., ECG front-end) with 3.3 V FPGA-based data acquisition subsystems in portable diagnostic devices. IC Role / Device Role / Timing Role: Ultra-low-voltage level shifter - preserves sub-1 V logic swing integrity while translating to standard I²C voltage levels for host processing. Use Value: Maintains signal fidelity for time-critical sensor data reads without introducing metastability or false ACKs due to marginal voltage thresholds. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C bus repeater applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9515BDGVR | Same pinout and function; lacks buffered-low B-side architecture - uses static offset, limiting cascade depth and requiring stricter VIL matching | Not suitable for B-side-to-B-side chaining or systems with marginal slave VOL; better for simple point-to-point translation | Select PCA9515BDGVR only when replacing legacy designs or when B-side cascade is unnecessary |
| TCA9517PWR | VSSOP-8 package (3.0 mm × 3.0 mm); identical electrical specs and timing - differs only in thermal resistance (RθJA = 187.6°C/W vs. 133.6°C/W for SOIC) | Preferred for space-constrained PCBs; requires adjusted thermal layout due to higher junction-to-ambient resistance | Choose TCA9517PWR for compact designs with adequate airflow or localized heatsinking |
Compared with PCA9515BDGVR, TCA9517DR enables deeper B-side cascading and tolerates wider VOL variation among slaves; compared with TCA9517PWR, the DR variant offers superior thermal performance in high-density layouts - selection depends on mechanical constraints and system-level thermal budget.
Availability
TCA9517DR is available at Aetrix Electronics and suitable for server backplane expansion, industrial PLC I/O interfacing, and telecom router control plane applications requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.
Supply support for TCA9517DR 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and communications markets.
The TCA9517DR belongs to TI's I²C interface and level-shifting portfolio, designed specifically to solve mixed-voltage I²C signal integrity challenges in high-reliability systems where bus extension, noise immunity, and power-domain isolation are critical.
FAQ
What is the minimum VCCA voltage supported by the TCA9517DR?
The TCA9517DR supports VCCA down to 0.9 V, enabling direct interface with ultra-low-voltage processors and ASICs. At this rail, the A-side input threshold remains at 0.3×VCCA = 0.27 V, and the output low voltage stays ≤0.2 V at 6 mA sink current - ensuring compatibility with sub-1 V logic families. This specification is validated across –40°C to 85°C.
Can the TCA9517DR be used with B-side ports connected in parallel?
No, the TCA9517DR must not have B-side ports (SDAB/SCLB) connected together. Its B-side driver architecture produces a buffered low (~0.5 V), which is not recognized as a valid low by another B-side input - causing bus lockup. The datasheet explicitly prohibits B-side-to-B-side connections; only A-side-to-B-side chaining or A-side star topologies are supported.
How does the EN pin behave during power-up of the TCA9517DR?
The EN pin of the TCA9517DR is internally pulled up to VCCB and remains inactive until both VCCA > 0.8 V and VCCB > 2.5 V are detected by the internal power-good circuit. This prevents spurious outputs during power sequencing. Once powered, EN must be driven high only when the I²C bus is idle - asserting EN mid-transaction may corrupt SCL/SDA timing and cause protocol errors.
What is the maximum recommended bus capacitance per side for reliable TCA9517DR operation?
The TCA9517DR is characterized for operation with up to 400 pF total bus capacitance on each side (A and B). Exceeding this limit increases rise/fall times beyond I²C specification limits, especially in fast-mode (400 kHz) operation. For systems approaching this limit, TI recommends increasing pull-up resistor values to maintain VOL compliance and avoid violating VILC (≤0.4 V) on the B-side.
Does the TCA9517DR support clock stretching, and what design considerations apply?
Yes, the TCA9517DR supports clock stretching, but requires careful pull-up resistor selection on the B-side to minimize overshoot during master/slave handoff. TI recommends increasing B-side pull-up resistance to reduce edge rate and suppress ringing - this ensures the stretched clock remains within VIL/VIH thresholds after repeater propagation delay. Overshoot exceeding VCCB + 0.5 V risks latch-up or false level detection.
TCA9517DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- TCA
- Package/Case:
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Translator Type:
- Voltage Level
- Channel Type:
- Bidirectional
- Number of Circuits:
- 1
- Channels per Circuit:
- 2
- Voltage - VCCA:
- 0.9 V ~ 5.5 V
- Voltage - VCCB:
- 2.7 V ~ 5.5 V
- Input Signal:
- -
- Output Signal:
- -
- Output Type:
- Open Drain
- Data Rate:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Features:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC (0.154", 3.90mm Width)
TCA9517DR FAQ
1.How can I place an order for TCA9517DR through Aetrix?
Please submit a Request for Quotation (RFQ) for TCA9517DR 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 TCA9517DR reliable?
The price and inventory of TCA9517DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TCA9517DR is usually 5 days.
3.What payment methods are accepted for TCA9517DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TCA9517DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TCA9517DR?
TCA9517DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TCA9517DR 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 TCA9517DR?
For technical support, including TCA9517DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TCA9517DR requirements.
6.How does Aetrix verify that TCA9517DR is sourced from the original manufacturer or authorized distributors?
All TCA9517DR 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 TCA9517DR meets industry standards.
7.What is the process for return or replacement of TCA9517DR?
All TCA9517DR units undergo pre-shipment inspection (PSI). If there is an issue with TCA9517DR, 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 TCA9517DR part is unused and in its original packaging.
Return procedure for TCA9517DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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