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Texas Instruments TCA39306DDFR
- Part No.:
- TCA39306DDFR
- Manufacturer:
- Texas Instruments
- Category:
- Translators, Level Shifters
- Package:
- Datasheet:
-
TCA39306DDFR.pdf
- Description:
- FM+ IC BUS AND SMBUS VOLTAGE TRA
- Quantity:
- Payment:
- Shipping:
Inventory:1,425
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Product details
Overview
TCA39306DDFR from Texas Instruments is a dual bidirectional I²C/SMBus/I³C voltage-level translator IC enabling seamless communication between 0.85-V and 5-V domains without direction control. It supports standard-mode (100 kHz), fast-mode (400 kHz), fast-mode plus (1 MHz), and I³C (12.5 MHz) protocols, features 5-V-tolerant I/O, and delivers ≤5.5 Ω typical RON at 3.3-V VREF1/5-V VREF2 for minimal signal distortion in mixed-voltage server backplanes.
For engineers reviewing the TCA39306DDFR datasheet, TCA39306DDFR pinout, TCA39306DDFR application, or TCA39306DDFR equivalent, this device addresses critical voltage translation challenges in multi-rail I²C systems-especially where bus isolation, speed-tiered device coexistence, or hot-plug I²C expansion are required.
Technical Context
The TCA39306DDFR implements two independent NFET-based bidirectional pass-gate channels (SCL1↔SCL2, SDA1↔SDA2), each with gate bias derived from VREF1 and VREF2 via an internal 200-kΩ resistor network. Its enable (EN) input controls conduction state without affecting voltage translation polarity or timing asymmetry.
Unlike discrete FET translators, it guarantees matched propagation delays (tPLH/tPHL ≤ 46 ns max at 50 pF load) and symmetrical RON across both directions, eliminating skew-induced I²C clock stretching. The device operates across –40°C to +125°C with 5.5-V absolute maximum I/O ratings and JESD22-compliant ESD protection (±2000-V HBM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Voltage Translation Range | 0.85 V ↔ 5 V bidirectionally (e.g., 1.8-V MCU ↔ 3.3-V sensor or 3.3-V controller ↔ 5-V peripheral) |
| Protocol Support | I²C standard/fast/fast-mode plus (100/400/1000 kHz), SMBus, PMBus, MDIO, and I³C up to 12.5 MHz |
| RON (Typical) | 3.5 Ω at 4.5-V EN, 64-mA load - enables <1-ns skew between SCL/SDA paths and preserves rise/fall times |
| Propagation Delay | 2 ns (min) to 46 ns (max) depending on VREF1/VREF2 and load - meets fast-mode plus timing budgets with 50-pF bus capacitance |
| ESD Protection | ±2000-V HBM, ±1000-V CDM - eliminates need for external TVS diodes in industrial/server I/O zones |
| Operating Temperature | –40°C to +125°C - supports deployment in telecom switching equipment and automotive-adjacent industrial controllers |
| Supply Flexibility | VREF1: 0.9–3.3 V; VREF2: 1.8–5.5 V - allows use with LDOs, battery rails, or mixed-domain SoCs without level-shifter cascading |
Pinout & Package
SOT-23-8 (DDF) package: 2.90 mm × 1.60 mm body, 0.65-mm pitch, surface-mount, flow-through pinout optimized for compact I²C trace routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 GND | Reference ground | Common return path for both voltage domains; must be low-inductance connection to avoid ground bounce during translation |
| 2 VREF1 | Low-side reference supply | Bias source for SCL1/SDA1 I/O; sets logic thresholds and enables translation from sub-1-V domains (e.g., 0.9-V AI accelerators) |
| 3 SCL1 | Low-voltage I²C clock | Open-drain bidirectional port referenced to VREF1; connects to 0.85–3.3-V controllers/responders |
| 4 SDA1 | Low-voltage I²C data | Open-drain bidirectional port referenced to VREF1; shares same RON and timing as SCL1 |
| 5 SDA2 | High-voltage I²C data | Open-drain bidirectional port referenced to VREF2; tolerates 5-V pull-ups while driving 1.8–5.5-V loads |
| 6 SCL2 | High-voltage I²C clock | Open-drain bidirectional port referenced to VREF2; matches SDA2 electrical behavior for synchronous operation |
| 7 VREF2 | High-side reference supply | Bias source for SCL2/SDA2 I/O; establishes EN threshold and enables 5-V tolerant operation |
| 8 EN | Enable control input | Active-high logic input (1.5–5.5 V); disconnects ports into high-Z when low, enabling bus isolation without power cycling |
Key Features
| Feature | Design Value |
|---|---|
| No-direction-pin bidirectional translation | Eliminates GPIO overhead and firmware complexity in resource-constrained microcontrollers |
| 5-V-tolerant I²C I/O ports | Supports direct interface to legacy 5-V peripherals without external resistive dividers or additional transistors |
| Flow-through pinout (SOT-23-8) | Enables straight-line PCB routing for SCL/SDA pairs-reducing crosstalk and stub length in high-speed I²C layouts |
| Lockup-free isolation at EN = Low | Prevents bus contention during hot-swap events or partial system resets, avoiding I²C bus lockup in modular systems |
| I³C compatibility (12.5 MHz) | Extends usability beyond legacy I²C to next-generation sensor hubs and memory interfaces requiring higher bandwidth |
Applications
| Server Baseboard Management | Industrial I/O Module Isolation |
|---|---|
|
Use Scenario: Connecting 1.2-V BMC processors to 3.3-V temperature sensors and fan controllers on a shared I²C bus. IC Role / Device Role / Timing Role: Voltage translator and bus isolator-enables BMC to communicate with legacy 3.3-V devices while preventing noise coupling during high-current fan PWM bursts. Use Value: Eliminates need for separate I²C buses or software-controlled multiplexing, reducing BOM count and firmware latency by >30%. |
Use Scenario: Isolating a 400-kHz PLC I/O expander from a 1-MHz motion controller on the same backplane I²C segment. IC Role / Device Role / Timing Role: Speed-tiered bus switch-EN pin disables translation during 1-MHz motion control cycles, preventing glitches in slower responders. Use Value: Enables deterministic real-time motion control without redesigning the entire I²C infrastructure or adding protocol bridges. |
| Telecom Router Control Plane | Hot-Pluggable Server Blade Interconnect |
|
Use Scenario: Bridging 1.8-V FPGA management I²C to 5-V power sequencers and voltage monitors in carrier-grade routers. IC Role / Device Role / Timing Role: Mixed-voltage translator with 5-V tolerance-handles FPGA I/O swing limitations while interfacing to legacy 5-V PMICs. Use Value: Avoids level-shifter cascading and associated timing jitter, ensuring reliable power sequencing across 100+ rail configurations. |
Use Scenario: Enabling safe insertion of a 3.3-V compute blade into a live 3.3-V backplane I²C bus without bus corruption. IC Role / Device Role / Timing Role: Hot-swap enabler-EN held low during insertion, then asserted only after blade power stabilization and bus IDLE detection. Use Value: Prevents SCL glitches and unintended START conditions during mechanical mating, eliminating field-reported I²C lockups in modular servers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional I²C voltage translation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9306DCUR | Single-channel, no EN pin, 1.2–3.6-V translation range only; lacks I³C support and 5-V tolerance | Not suitable for 5-V peripherals or hot-swap isolation; limited to low-voltage mobile/embedded use cases | Select only if translating between ≤3.6-V domains and EN control is unnecessary |
| TXS0102DCUR | Auto-direction sensing, no EN pin, 1.65–3.6-V VCCA/VCCB range; higher RON (12 Ω typ) and slower tPHL (10 ns min) | Cannot isolate bus segments; unsuitable for speed-tiered systems or I³C; requires external pull-ups on both sides | Choose only for cost-sensitive, non-isolating, ≤3.6-V applications where auto-direction suffices |
Compared with PCA9306DCUR and TXS0102DCUR, the TCA39306DDFR uniquely combines 5-V tolerance, hardware-enforced isolation via EN, and I³C readiness-making it the only option for robust, future-proof I²C infrastructure in servers, telecom, and industrial automation.
Availability
TCA39306DDFR is available at Aetrix Electronics and suitable for server baseboard management, telecom router control planes, industrial I/O modules, and hot-pluggable compute blade interconnects requiring stable component supply across extended temperature and mixed-voltage environments.
Supply support for TCA39306DDFR 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 solutions, with over 50 years of innovation in precision analog and interface ICs.
The TCA39306DDFR belongs to TI's high-reliability I²C/SMBus translation portfolio, designed specifically for mission-critical infrastructure where voltage domain bridging, bus isolation, and protocol scalability (I²C → I³C) are mandatory.
FAQ
What is the minimum VREF1 voltage supported by the TCA39306DDFR?
The TCA39306DDFR supports VREF1 down to 0.85 V per the datasheet's recommended operating conditions. This enables direct interfacing with ultra-low-voltage processors and AI accelerators operating at sub-1-V logic levels, while maintaining full bidirectional translation functionality with VREF2 as low as 1.8 V.
Can the TCA39306DDFR be used without connecting the EN pin?
Yes-the TCA39306DDFR operates with EN tied to VREF2 (via the internal 200-kΩ resistor) for always-on translation. However, leaving EN unconnected risks floating input states; TI recommends tying EN directly to VREF2 or using an external pull-up to ensure predictable enable behavior and avoid unintended isolation.
Does the TCA39306DDFR require external pull-up resistors on both sides of the I²C bus?
Yes-external pull-up resistors are mandatory on both SCL1/SDA1 (to VREF1) and SCL2/SDA2 (to VREF2). The TCA39306DDFR does not include internal pull-ups; resistor values must be selected based on bus capacitance, speed mode, and voltage levels per TI's application note SLVA689.
How does the TCA39306DDFR handle I²C bus arbitration when multiple controllers are present on different voltage domains?
The TCA39306DDFR preserves native I²C arbitration behavior because it functions as a passive bidirectional switch-not a protocol-aware repeater. Arbitration resolution occurs transparently across domains, provided pull-up resistors are correctly sized and bus capacitance remains within 400 pF (fast-mode) or 550 pF (fast-mode plus) limits.
Is the TCA39306DDFR pin-compatible with other Texas Instruments level shifters like the PCA9306?
No-the TCA39306DDFR uses an 8-pin SOT-23 (DDF) package with distinct pin mapping (e.g., EN on pin 8, VREF1 on pin 2), whereas the PCA9306 uses a 8-pin VSSOP (DCU) with EN absent and different terminal assignments. PCB layout and schematic symbols are not interchangeable.
TCA39306DDFR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Translator Type:
- Voltage Level
- Channel Type:
- Bidirectional
- Number of Circuits:
- 1
- Channels per Circuit:
- -
- Voltage - VCCA:
- 0.85 V ~ 5.5 V
- Voltage - VCCB:
- 1.65 V ~ 5.5 V
- Input Signal:
- -
- Output Signal:
- -
- Output Type:
- Open Drain, Push-Pull
- Data Rate:
- -
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Features:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8 Thin, TSOT-23-8
TCA39306DDFR FAQ
1.How can I place an order for TCA39306DDFR through Aetrix?
Please submit a Request for Quotation (RFQ) for TCA39306DDFR 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 TCA39306DDFR reliable?
The price and inventory of TCA39306DDFR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TCA39306DDFR is usually 5 days.
3.What payment methods are accepted for TCA39306DDFR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TCA39306DDFR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TCA39306DDFR?
TCA39306DDFR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TCA39306DDFR 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 TCA39306DDFR?
For technical support, including TCA39306DDFR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TCA39306DDFR requirements.
6.How does Aetrix verify that TCA39306DDFR is sourced from the original manufacturer or authorized distributors?
All TCA39306DDFR 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 TCA39306DDFR meets industry standards.
7.What is the process for return or replacement of TCA39306DDFR?
All TCA39306DDFR units undergo pre-shipment inspection (PSI). If there is an issue with TCA39306DDFR, 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 TCA39306DDFR part is unused and in its original packaging.
Return procedure for TCA39306DDFR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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