TCA39306DDFR - Dual I2C/I3C Bidirectional Level Translator | TI
MPN: TCA39306DDFR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.45 | $0.45 |
| 10 | $0.38 | $3.80 |
| 100 | $0.2757 | $27.57 |
| 500 | $0.24 | $120.00 |
| 1,000 | $0.21 | $210.00 |
TCA39306DDFR Overview
A voltage-level translator (also called a logic level shifter or voltage translator) is an integrated circuit that allows digital signals referenced to one supply domain to drive inputs in a different supply domain. Within the system hierarchy, level translators sit in the logic and interface IC family, bridging mismatched voltage domains between microcontrollers, sensors, and peripherals. Bidirectional translators such as the TCA39306 are essential for open-drain buses like I2C, where the same two wires (SDA and SCL) carry traffic in both directions.
Key features include automatic bidirectional translation without a direction pin, support for Standard-mode (100 kbps), Fast-mode (400 kbps), and Fast-mode Plus (1 Mbps) I2C, plus I3C compatibility at 12.5 MHz, and an enable (EN) input for bus isolation. The low ON-state resistance (RON) of the internal pass-gate switches minimizes signal degradation and bus loading.
Technically, the TCA39306 implements the reference-voltage biased switch architecture: VREF1 biases one side of the pass gate and VREF2 the other, so the open-drain pull-up levels define the translated logic levels. This pass-switch topology draws negligible static current and preserves I3C push-pull signaling on the SDA line, which open-drain-only solutions cannot support.
Typical applications include mixed-voltage I2C bus segments (for example, a 1.8 V sensor side talking to a 3.3 V or 5 V controller side), SMBus systems in servers and power supplies, and emerging I3C peripherals in mobile and IoT designs. The tiny TSOT-23-8 footprint suits space-constrained board layouts.
Design consideration: choose pull-up resistors on both sides appropriately - lower-value pull-ups (for example 1 kOhm to 4.7 kOhm) are needed for Fast-mode Plus and I3C rise-time compliance, while the EN pin can be driven to isolate the bus during reset sequences.
This page synthesizes distributor pricing, drop-in alternative analysis, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for TCA39306DDFR — 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:
TCA39306DDCR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
TCA39306DDFR Maximum Ratings & Electrical Characteristics
| Product Type | Dual bidirectional voltage-level translator |
| Translator Channels | 2-bit (SDA, SCL) |
| Bus Compatibility | I2C (Standard, Fast, Fast-mode Plus), SMBus, I3C |
| I3C Maximum Speed | 12.5 MHz |
| VREF1 Supply Range | 0.9 V to 3.3 V |
| VREF2 Supply Range | 1.8 V to 5.5 V |
| Translation Voltage Range | 0.85 V to 5 V |
| Direction Control | Not required (auto-direction bidirectional) |
| Enable Pin | Yes (EN input) |
| Output Type | Open-drain pass-switch (low RON) |
| Package | TSOT-23-8 (DDF) |
| Mounting Type | Surface Mount |
TCA39306DDFR tsot-23-8 (ddf) Pin Configuration Guide
Pin configuration for TCA39306DDFR (tsot-23-8 (ddf) 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 TCA39306DDFR.
Refer to the datasheet for full pin configuration.
Typical Applications
TCA39306DDFR is suitable for 6 applications: Mixed-Voltage I2C Bus Bridging, I3C Peripheral Migration, SMBus Systems in Servers and Power Supplies, Industrial Sensor Modules, Battery-Powered Wearables and IoT, Automotive Infotainment and Cluster Peripherals.
Mixed-Voltage I2C Bus Bridging
The TCA39306 directly addresses the most common I2C integration problem: a 1.8 V microcontroller or sensor that must share SDA and SCL with a 3.3 V or 5 V peripheral domain. Its VREF1 range of 0.9 V to 3.3 V and VREF2 range of 1.8 V to 5.5 V cover every mainstream logic rail combination, and the pass-switch topology translates open-drain signaling automatically with no direction pin. Place the device between the two bus segments and fit pull-up resistors to each side's rail - 4.7 kOhm for Standard-mode or 1 to 2 kOhm for Fast-mode Plus. The low ON-state resistance keeps rise times short even under bus capacitance, and the EN pin lets firmware isolate a misbehaving slave without power-cycling the rails.
Recommended
I3C Peripheral Migration
Designs migrating from legacy I2C to MIPI I3C need a translator that preserves push-pull signaling on the SDA line, which open-drain-only switch solutions cannot do reliably at speed. The TCA39306 is verified I3C compatible at 12.5 MHz per the TI datasheet, making it suitable for connecting new I3C sensor hubs to legacy 1.8 V or 3.3 V rails in smartphones, wearables, and IoT edge devices. The 2-bit channel count exactly matches the I3C SDA/SCL pair, so a single TSOT-23-8 device handles the entire bus. Its 0.9 V minimum VREF1 also supports next-generation sub-1 V logic. Verify bus capacitance stays within the I3C specification for the target data rate, since the pass-switch RON adds series impedance to the path.
Recommended
SMBus Systems in Servers and Power Supplies
Server management planes, battery management, and AC/DC power supplies commonly use SMBus at 3.3 V or 5 V while the host controller runs at lower voltages. The TCA39306 is explicitly SMBus compatible and its 5.5 V maximum VREF2 tolerates 5 V SMBus segments directly. The EN input is especially valuable here: it allows a BMC or hot-swap controller to isolate the bus segment during backplane insertion, address re-enumeration, or fault recovery, preventing a stuck low line from blocking system startup. The compact TSOT-23-8 package fits dense power-supply secondary-side layouts. Fit pull-ups appropriate to the 100 kbps SMBus timing and observe the SMBus 1.0/2.0 voltage-level requirements on each side of the translator.
Recommended
Industrial Sensor Modules
Industrial controllers often run 5 V or 3.3 V logic while modern low-power sensors favor 1.8 V rails to cut quiescent consumption. The TCA39306's 0.85 V to 5 V translation window bridges these domains in a single 2-bit device covering the complete SDA/SCL pair. Because the pass-switch draws negligible static current, it suits battery-backed or energy-harvesting field nodes where every microamp counts. The wide 0.9 V VREF1 floor also accommodates heavily loaded or brown-out conditions common on long factory-floor cable runs. Its industrial temperature capability and small footprint suit DIN-rail and IP67 sensor-module designs. Isolate the segment with EN during sensor module hot-plug events to protect the host controller from transient line conditions.
Recommended
Battery-Powered Wearables and IoT
Wearables combine a 1.8 V or 0.9 V low-power sensor domain with a 3.3 V radio or secure-element domain, and the TCA39306's 0.9 V minimum VREF1 makes it one of the few translators covering this extreme. Its tiny TSOT-23-8 footprint conserves board area in slim device stacks, and the near-zero static current of the pass-switch architecture preserves battery life during sleep states where the bus is idle. The EN pin allows the application processor to disconnect the bus entirely in deep-sleep, eliminating domain leakage paths. For I3C-equipped next-generation wearables, the verified 12.5 MHz compatibility future-proofs the design. Choose pull-up values that balance rise time against the pull-up current budget during active communication bursts.
Recommended
Automotive Infotainment and Cluster Peripherals
In automotive cockpit electronics, a 3.3 V SoC frequently must address 5 V peripherals such as touch controllers or EEPROM on shared I2C rails, and the TCA39306's 0.85 V to 5 V translation window handles both directions on one 2-bit device. The EN input supports controlled bus bring-up after crank conditions and protects against brown-out glitches during load-dump transients upstream. Its low ON-state resistance maintains signal integrity over the longer PCB traces typical of cluster boards. Place the translator close to the lower-voltage SoC side and keep the 5 V segment traces short to limit coupled noise. Confirm AEC-Q100 qualification requirements for your tier before selecting the standard-grade part for production.
Recommended
Recommended Products Summary
Engineering reference data for TCA39306DDFR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TCA39306DDCR | TCA39306DGVR |
|---|---|---|---|
| Package | TSOT-23-8 (DDF) | SOT-23-8 (DDC) - same footprint, standard body | SOT-563 (DGV) - smaller, footprint change |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Bus Compatibility | I2C (Std/Fm/Fm+), SMBus, I3C 12.5 MHz | I2C (Std/Fm/Fm+), SMBus, I3C 12.5 MHz | I2C (Std/Fm/Fm+), SMBus, I3C 12.5 MHz |
| VREF1 Range | 0.9 V to 3.3 V | 0.9 V to 3.3 V | 0.9 V to 3.3 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 Pin | Not required | Not required | Not required |
| Enable Pin | Yes (EN) | Yes (EN) | Yes (EN) |
| Channels | 2-bit (SDA/SCL) | 2-bit (SDA/SCL) | 2-bit (SDA/SCL) |
Key Differentiators
- Native I3C support at 12.5 MHz (vs PCA9306)
- Lower VREF1 floor (vs PCA9306)
- Footprint-identical family variants (vs TCA39306DDCR)
Design Notes
Place the TCA39306 close to the lower-voltage (VREF1) device to keep that segment's stub length minimal, since the low-voltage side is typically the most noise-sensitive. Fit separate pull-up resistors on both sides to their respective rails - never a single pull-up spanning the translator, which defeats level translation. For Fast-mode Plus (1 Mbps) or I3C at 12.5 MHz, target 1 kOhm to 2 kOhm pull-ups and verify rise time against total bus capacitance; for Standard-mode, 4.7 kOhm is typical.
Both VREF1 and VREF2 must be present for the pass-switch to bias correctly; if one rail may power up first, sequence VREF1 to rise before or with VREF2 per the TI datasheet power-up behavior, or use the EN pin held low until both rails are valid. Add 0.1 uF ceramic decoupling capacitors at both VREF pins, placed within a few millimeters of the package. Avoid series resistors larger than needed on the bus, as the pass-switch RON adds to the total path impedance and affects rise time.
Do not use the TCA39306 for push-pull CMOS GPIO translation - it is an open-drain pass-switch designed for I2C/SMBus/I3C buses; using it on push-pull lines can cause contention. Ensure EN is not left floating in systems requiring defined bus states at reset - tie it to a controlled logic level or a supervisory output. Also confirm body height: the DDF (TSOT-23-8) is thinner than the DDC (SOT-23-8) variant, which matters in constrained enclosure stacks.
Compliance Information
Compliance data was not present in the provided verified web data. RoHS, REACH, and lead-free status should be confirmed on the TI product page or its environmental documentation before production use.
