TCA39306DTMR - Dual I2C/SMBus/I3C Bidirectional Level Translator | TI
MPN: TCA39306DTMR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.52 | $5.20 |
| 100 | $0.34 | $34.00 |
| 500 | $0.27 | $135.00 |
| 1,000 | $0.22 | $220.00 |
TCA39306DTMR Overview
A voltage-level translator is a logic-family interface IC that bridges digital signals between circuits operating at different supply rails, a member of the broader voltage-translation and logic-translation hierarchy within standard logic ICs. For open-drain buses such as I2C and SMBus, a bidirectional translator is required because data flows both ways on the same line without a direction-control pin; the TCA39306 solves this by using pass-gate switches with integrated pull-up references tied to each side's reference voltage.
Key features include standard-mode (100 kbps), fast-mode (400 kbps), and fast-mode-plus (1 Mbps) I2C compatibility, I3C compatibility up to 12.5 MHz, an enable (EN) input for power sequencing and bus isolation, and very low ON-state resistance (RON) of the internal switches, which minimizes signal attenuation and allows external pull-up resistors to remain small. Because there is no direction pin, both channels (SDA and SCL) translate automatically as the bus arbitrates.
Technically, the device uses two NMOS pass transistors per channel: when B-side is high, the switch conducts and the A-side tracks it; when A-side is pulled low, the switch passes the low level through. The EN pin must be driven to VREF1 for normal operation and can be grounded to place the bus in high-impedance, useful for hot-swapping and multi-master isolation.
Typical applications include mixed-voltage MCU-to-sensor I2C links, server and industrial automation bus translation, and consumer electronics peripheral interfaces where a 1.8V controller must talk to a 3.3V or 5V peripheral.
Design consideration: choose pull-up resistors for both rails carefully; smaller pull-ups speed rising edges but increase sink current through the internal switch, so follow the TI TCA39306 EVM User's Guide (SCPU045) guidance on load capacitance and pull-up selection.
This page synthesizes distributor pricing context, drop-in alternative analysis, and practical design notes that go beyond the manufacturer datasheet.
Drop-in alternatives for TCA39306DTMR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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Request AlternativesTCA39306DTMR Maximum Ratings & Electrical Characteristics
| Function | Dual (2-bit) bidirectional voltage-level translator |
| Bus Compatibility | I2C, SMBus, I3C |
| I3C Speed Support | 12.5 MHz |
| VREF1 Range | 0.9 V to 3.3 V |
| VREF2 Range | 1.8 V to 5.5 V |
| Translation Range | 0.85 V to 5 V |
| Channels | 2 (SDA, SCL) |
| Direction Control | None (bidirectional, automatic) |
| Enable Pin | Yes (EN input) |
| I2C Modes Supported | Standard-mode, Fast-mode, Fast-mode Plus |
| Package | 8-X2SON (1.35 mm x 0.8 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (260 C unlimited) |
| REACH | Compliant |
| Packaging | Tape and Reel (DTMR suffix) |
TCA39306DTMR 8-x2son (1.35 mm x 0.8 mm) Pin Configuration Guide
Pin configuration for TCA39306DTMR (8-x2son (1.35 mm x 0.8 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for TCA39306DTMR.
Refer to the datasheet for full pin configuration.
Typical Applications
TCA39306DTMR is suitable for 6 applications: Mixed-Voltage MCU-to-Sensor I2C Links, Server and Data Center I3C Management Buses, Industrial Automation Control Interfaces, Hot-Swap and Power-Sequenced Subsystems, Consumer Electronics Peripheral Interfaces, Test and Measurement Instrumentation.
Mixed-Voltage MCU-to-Sensor I2C Links
Modern microcontrollers commonly run at 1.8V while many industrial and consumer sensors, EEPROMs, and RTCs still operate at 3.3V or 5V. The TCA39306DTMR bridges this gap directly: VREF1 connects to the 1.8V MCU rail (within its 0.9V to 3.3V window) and VREF2 to the peripheral rail up to 5.5V. Because the pass-gate architecture needs no direction pin, SDA and SCL translate automatically during both controller writes and peripheral reads, including clock stretching and multi-master arbitration. Its low ON-state resistance preserves logic levels with modest pull-ups, and the 1.35mm x 0.8mm X2SON package fits beside the connector on dense sensor boards.
Recommended
Server and Data Center I3C Management Buses
Server platforms increasingly use I3C for DIMM sideband, power-supply telemetry, and sensor aggregation because I3C supports higher speeds and in-band interrupts. The TCA39306DTMR supports I3C up to 12.5 MHz, letting a 1.0V-to-1.8V baseboard management controller domain communicate with 3.3V or 5V legacy management components without protocol conversion. The EN input allows the BMC to isolate a faulted bus segment during hot-plug events, and the low RON pass gates keep the added capacitance small, which matters when dozens of addressable devices load the bus. Follow the TI EVM guide SCPU045 for pull-up sizing at these speeds.
Recommended
Industrial Automation Control Interfaces
Industrial control boards frequently mix a low-voltage microcontroller domain with 5V legacy I2C peripherals such as port expanders and ADCs on noisy factory floors. The TCA39306DTMR translates between 0.85V and 5V, covering the 0.9V to 3.3V VREF1 range and 1.8V to 5.5V VREF2 range of typical PLC I/O stacks. Its automatic bidirectional behavior handles SMBus-style commands without firmware involvement, while the EN pin supports power-sequenced startup where the 5V field rail arrives before the logic rail. The small X2SON footprint and surface-mount construction suit high-density I/O modules and distributed remote-sensor boards.
Recommended
Hot-Swap and Power-Sequenced Subsystems
In removable cards, docking interfaces, and modular instruments, an I2C bus may be connected while one side is unpowered. The TCA39306DTMR's EN input places both channels in high impedance when pulled low, isolating the unpowered domain and preventing back-powering through clamp diodes. During controlled power-up, firmware asserts EN only after both VREF1 (0.9V to 3.3V) and VREF2 (1.8V to 5.5V) rails are stable, meeting sequencing requirements cleanly. Because translation resumes transparently without re-initialization, the bus controller needs no special recovery code after every insertion or rail-cycling event, simplifying system bring-up.
Recommended
Consumer Electronics Peripheral Interfaces
Smartphones, tablets, wearables, and smart-home devices pair 1.8V or lower application processors with 3.3V touch controllers, audio codecs, and fuel gauges. The TCA39306DTMR occupies under 1.1 mm squared of board area in its 1.35mm x 0.8mm X2SON package, making it practical even inside the connector keep-out region of a wearable PCB. I2C fast-mode-plus (1 Mbps) support ensures fast-mode-class displays and sensors are not throttled, and I3C compatibility future-proofs the design as peripheral vendors transition. Low ON-state resistance keeps signal integrity high on the short, capacitance-limited traces typical of portable layouts.
Recommended
Test and Measurement Instrumentation
Bench instruments and probe pods must talk to DUTs at arbitrary logic levels, so internal controller buses routinely need translation. The TCA39306DTMR covers 0.85V to 5V translation, letting a fixed 3.3V instrument FPGA or MCU domain communicate with DUT boards powered at 1.2V, 1.8V, 2.5V, 3.3V, or 5V simply by tying VREF2 to the DUT rail. The EN pin lets firmware park the bus in high impedance between tests, avoiding interference with DUT self-test routines. TI's own TCA39306 evaluation module (user guide SCPU045) demonstrates exactly these usage patterns, including DUT locations for different package options.
Recommended
Recommended Products Summary
Engineering reference data for TCA39306DTMR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TCA9517ADGKR | PCA9306DCUR |
|---|---|---|---|
| Package | 8-X2SON (1.35 mm x 0.8 mm) | VSSOP-8 (DGK) - different footprint, not drop-in | VSSOP-8 (DCT) - different footprint, not drop-in |
| Brand | Texas Instruments | Texas Instruments | NXP / TI second source |
| Channels | 2 (SDA/SCL) | 1 buffered channel pair | 2 |
| VREF1 Range | 0.9 V to 3.3 V | 0.9 V to 5.5 V (A-side up to 5.5 V) | 1.0 V to 3.6 V |
| VREF2 Range | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Direction Control | None (automatic bidirectional) | None (buffered, automatic) | None (automatic bidirectional) |
| Enable Pin | Yes (EN) | Yes (EN1/EN2) | Yes (EN) |
| Architecture | Pass-gate switch, low RON | Buffer/driver type | Pass-gate switch |
Key Differentiators
- I3C compatibility up to 12.5 MHz (vs PCA9306DCUR)
- Extremely small 8-X2SON footprint (vs TCA9517ADGKR)
- Wider low-side VREF1 window down to 0.9 V (vs PCA9306DCUR)
Design Notes
The TCA39306 is a pass-gate translator, not a buffer: rising edges come from external pull-ups on both sides. Model total bus capacitance per segment (device pins + trace) and size pull-ups so the rise time meets your speed class - roughly 1 kOhm to 2.2 kOhm for fast-mode-plus on a loaded bus, up to 10 kOhm for short standard-mode runs. At I3C 12.5 MHz, capacitance budget is tight; follow the TI TCA39306 EVM User's Guide (SCPU045) load-capacitance selection section before committing to a layout.
VREF1 must be between 0.9V and 3.3V and VREF2 between 1.8V and 5.5V per the TI product page; neither rail may exceed the other's window even transiently. Enforce sequencing with the EN pin: hold EN low until both rails are stable, then assert EN to VREF1. This prevents back-powering an unpowered domain through the pass gates, a common failure in hot-swap and battery-backed designs. Decouple both VREF pins with at least 0.1 uF ceramics placed within 2 mm of the pins given the 1.35 mm x 0.8 mm package.
The 8-X2SON (DTM) footprint is unusual - most I2C translators ship in VSSOP-8 or MSOP-8 - so a second source generally requires a PCB revision, not just a BOM swap. Also, many engineers mistake the tiny X2SON land pattern for a chip-scale BGA; solder masking and stencil apertures need careful tuning per TI's package mounting resources. Finally, do not omit pull-ups on the EN pin if it is driven by an open-drain signal, or the bus will float between states during startup.
Compliance Information
PartGenie listing states REACH compliant and MSL level 1 (260 C unlimited); RoHS listed as not applicable in that source but not confirmed by TI - verify on the official TI product page.
