TCA39306DCURQ1 - Dual I2C/I3C Level Translator 12.5MHz | TI
MPN: TCA39306DCURQ1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.89 | $0.89 |
| 10 | $0.72 | $7.20 |
| 100 | $0.58 | $58.00 |
| 500 | $0.52 | $260.00 |
| 1,000 | $0.59 | $590.00 |
TCA39306DCURQ1 Overview
A voltage-level translator is an interface IC that allows devices operating at different supply voltages to communicate over the same two-wire or multi-drop bus. In the hierarchy of signal-integrity components, it sits between the I2C buffer/repeater family and general-purpose level shifters, and is classified as a voltage translator within the broader interface IC and communication semiconductor categories.
Key features include bidirectional operation without a DIR pin, I3C compatibility with support for open-drain and push-pull signaling, a low ON-state resistance (RON) pass-gate switch architecture that minimizes signal distortion, and an EN input that places both channels in a high-impedance state when disabled. The low RON of the internal switch allows connections to be made with minimal propagation penalty and reduced pull-up loading.
Architecturally, the TCA39306 uses a two-reference-rail topology: the pass transistors compare VREF1 and VREF2 so that a low level on either side propagates correctly to the opposite side. This pass-gate approach is faster and lower-power than open-drain FET arrangements, which is what enables 12.5MHz (Fast-mode Plus and I3C-class) operation.
Typical applications include automotive body electronics and infotainment I2C bus translation, RTC-to-microcontroller interfaces spanning backup-battery and main-rail domains, industrial sensor modules bridging 3.3V MCUs to 5V peripherals, and I3C sensor hubs. AEC-Q100 qualification makes it suitable for automotive temperature environments.
Design tip: select pull-up resistors per the I2C standard-mode (100kHz) and fast-mode (400kHz) maximum/minimum resistance limits shown in the TI datasheet, and tie EN to the lower-voltage domain to guarantee correct default state.
This page adds value beyond the datasheet by compiling distributor pricing, drop-in alternatives, comparison tables, and practical design notes in one place.
Drop-in alternatives for TCA39306DCURQ1 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TCA39306DCUR
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9306DCURQ1
✅ Drop-In📋 Reference alternative (not in catalog)
TXS0102QDCURQ1
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9306DC
✅ Drop-In📋 Reference alternative (not in catalog)
TCA39306DCURQ1 Specifications
| Function | Dual bidirectional voltage-level translator |
| Bus Compatibility | I2C, SMBus, I3C |
| Channels | 2 |
| Circuits | 1 |
| 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 |
| Maximum Data Rate | 12.5 MHz |
| Direction Control | No direction pin (automatic bidirectional) |
| Enable Input | Yes (EN) |
| Package | 8-VSSOP (DCU) |
| Mounting Type | Surface Mount |
| Qualification | AEC-Q100 (automotive) |
| MSL Level | 1 - 260C - UNLIM |
| RoHS Status | Compliant |
| Packaging | Tape & Reel (R suffix) |
TCA39306DCURQ1 Pin Configuration
| Pin 1 | A1 — Channel 1 port A (VREF1 side) |
| Pin 2 | A2 — Channel 2 port A (VREF1 side) |
| Pin 3 | GND — Ground reference |
| Pin 4 | EN — Enable input; low puts both channels in high impedance |
| Pin 5 | VREF2 — Reference voltage for side B (1.8V to 5.5V) |
| Pin 6 | B2 — Channel 2 port B (VREF2 side) |
| Pin 7 | B1 — Channel 1 port B (VREF2 side) |
| Pin 8 | VREF1 — Reference voltage for side A (0.9V to 3.3V) |
Typical Applications
TCA39306DCURQ1 is suitable for 6 applications: Automotive Body Electronics and Infotainment, RTC Backup-Power Domain Interface, Industrial Sensor Modules, I3C Sensor Hubs, Server and Networking Board Management, Consumer Electronics Mixed-Rail Buses.
Automotive Body Electronics and Infotainment
In automotive body-control modules, cluster displays, and infotainment head units, I2C buses frequently span mixed voltage domains: a 3.3V microcontroller must talk to 5V touch controllers, LED drivers, or EEPROMs. The TCA39306DCURQ1 bridges these domains bidirectionally without a direction pin, and its AEC-Q100 qualification and -Q1 ordering suffix satisfy automotive quality flows including PPAP documentation. Its 12.5MHz capability covers Fast-mode Plus command buses and emerging I3C sensor links, while the EN pin lets the host tri-state the bus during system power-up to prevent partial-power communication faults.
Recommended
RTC Backup-Power Domain Interface
A common automotive and industrial pattern places a real-time clock on a coin-cell or supercap backup rail while the MCU sits on the main 3.3V or 5V rail. Directly tying the two I2C buses back-powers the RTC domain and drains the reserve cell. The TCA39306DCURQ1 isolates the domains: its pass-gate references each side to its own VREF rail, limiting cross-domain current, and TI's E2E forum specifically discusses this part for latch-up countermeasures in RTC backup designs. Asserting EN low during main-rail down-transitions fully disconnects the main bus from the battery-backed device.
Recommended
Industrial Sensor Modules
Industrial sensor modules commonly mix a 3.3V microcontroller with 5V legacy peripherals such as ADCs, calibration EEPROMs, and fan controllers on one I2C or SMBus. The TCA39306DCURQ1 translates both directions automatically, so multi-master arbitration and clock stretching pass through transparently. Its low ON-state resistance keeps signal edges sharp on cable-extended or high-capacitance bus segments, and 12.5MHz capability provides headroom for I3C-based smart-sensor upgrades. The DCU package's small 2x2mm-class footprint fits dense DIN-rail and sensor-head PCBs.
Recommended
I3C Sensor Hubs
Modern smartphone, AR/VR, and IoT sensor hubs migrate from I2C to I3C for higher throughput and in-band interrupts. The TCA39306DCURQ1 is explicitly I3C-compatible per TI documentation and supports up to 12.5MHz signaling, covering I3C SDR data rates while remaining backward-compatible with legacy I2C targets on the same bus. When the hub SoC runs at 1.0-1.8V and peripheral sensors run at 1.8V or 3.3V, the part's 0.85V minimum VREF1 support enables translation out of the lowest core-adjacent rails that older translators cannot handle.
Recommended
Server and Networking Board Management
Server and switch platforms use SMBus for power-supply telemetry, fan controllers, DIMM SPD, and hot-swap controllers. These buses cross voltage domains between the BMC (often 1.8V or 3.3V) and 5V legacy devices. The TCA39306DCURQ1 provides transparent bidirectional SMBus translation; its EN input supports bus segmentation during fault isolation, letting firmware quarantine a stuck segment. The 12.5MHz rating future-proofs designs transitioning to I3C-based management (MCTP over I3C), and the DCU package fits the crowded BMC-area layout of ATCA and Open Compute boards.
Recommended
Consumer Electronics Mixed-Rail Buses
Consumer devices such as set-top boxes, smart speakers, and wearables pair low-voltage application processors with 1.8V, 3.3V, or 5V peripheral ICs on shared I2C buses. The TCA39306DCURQ1's wide 0.85V-to-5V translation window covers virtually all consumer rail combinations, including 1.05V and 1.2V PMIC-adjacent domains. Its MSL 1 rating (260C unlimited floor life) simplifies high-volume reflow assembly, and RoHS compliance meets global market requirements. Even though it is automotive-qualified, the same die serves cost-sensitive consumer builds with added margin.
Recommended
Recommended Products Summary
Engineering reference data for TCA39306DCURQ1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TCA39306DCUR | PCA9306DCURQ1 | TXS0102QDCURQ1 | PCA9306DC |
|---|---|---|---|---|---|
| Package | 8-VSSOP (DCU) | 8-VSSOP (DCU) - same | 8-VSSOP (DCU) - same | 8-VSSOP (DCU) - same | VSSOP-8 (DC) - same footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors |
| I3C Compatibility | Yes | Yes | No (I2C/SMBus only) | Not I3C-rated | No |
| AEC-Q100 Qualification | Yes (-Q1) | No | Yes | Yes | No |
| VREF1 Range | 0.9 V to 3.3 V | 0.9 V to 3.3 V | 1.0 V to 3.3 V (typ.) | 1.2 V to 3.6 V (VCCA) | 1.0 V to 3.6 V (typ.) |
| VREF2 Range | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.65 V to 5.5 V (VCCB) | 1.8 V to 5.5 V |
| Enable Pin | Yes (EN) | Yes (EN) | Yes (EN) | Yes (OE) | Yes (EN) |
Key Differentiators
- Explicit I3C compatibility at 12.5MHz (vs PCA9306DCURQ1)
- Automotive AEC-Q100 qualification (vs TCA39306DCUR)
- Bus-optimized pass gate vs general-purpose translation (vs TXS0102QDCURQ1)
- Trade-off: requires external pull-ups (vs TXS0102QDCURQ1)
Design Notes
Pull-up resistor selection is the primary design task. The TI datasheet (Figures 9-3 and 9-4) plots maximum and minimum allowable pull-up resistance for standard-mode (100kHz) and fast-mode (400kHz) operation. Size Rp so that (a) VOL sinking current yields a valid low and (b) RC rise time stays within the bus spec: Rp_max roughly = t_rise / (0.8473 x Cbus). With 100pF bus capacitance at 400kHz, typical pull-ups land in the 1k-3k range. Verify with the actual figures in the manufacturer datasheet for your rail voltages.
Both VREF1 (0.9V-3.3V) and VREF2 (1.8V-5.5V) must be present for the pass-gate switches to bias correctly. Sequence considerations: if one rail is absent while the bus is active, the translator cannot guarantee signal integrity - gate the EN pin with a supervisor or power-good signal from the lower rail so channels enter high-Z until both domains are valid. Estimated: this adds no quiescent bus load beyond the translator's own supply current, which is small for battery-backed RTC domains.
Do not treat the TCA39306 like a push-pull auto-direction shifter such as TXS0102: the pass-gate topology relies on external pull-ups and open-drain-style bus signaling, so actively driven push-pull outputs on both sides can contend. When replacing a TXS0102, audit each bus segment for push-pull masters. Also avoid leaving EN floating - tie it through a pull-down or drive it from GPIO so the bus state is defined during reset, preventing spurious ACK/NACK corruption at startup.
Compliance Information
RoHS compliant and MSL 1 (260C unlimited) per PartGenie/TI compliance summary; AEC-Q100 per -Q1 ordering suffix confirmed by Arrow and TI product pages. REACH, halogen-free, and conflict-minerals statuses not stated in provided data.
