PCA9306DCTR - Dual Bidirectional I2C Level Translator | TI
N.º da peça: PCA9306DCTR ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $0.79 | $0,79 |
| 10 | $0.68 | $6,80 |
| 100 | $0.52 | $52,00 |
| 500 | $0.43 | $215,00 |
| 1.000 | $0.35 | $350,00 |
PCA9306DCTR Visão geral
A voltage-level translator is an interface IC that connects two digital circuits operating at different supply voltages, such as a 1.8V microcontroller driving a 3.3V or 5V sensor bus. Within the interface-IC hierarchy (level translator -> bus switch -> interface IC -> mixed-signal semiconductor), the PCA9306 is a passive-switch architecture: it uses two N-channel pass transistors rather than active driven buffers, so it does not require a direction pin.
Key features include bidirectional voltage translation between 1.2V and 5V rails with no direction-control signal, a low ON-state resistance (RON) pass-switch design that minimizes propagation delay and signal distortion, an active-high EN input that isolates both buses when low, and support for I2C, SMBus, PMBus, MDIO, UART, low-speed SDIO, and general two-signal GPIO interfaces. The dual-channel topology handles SCL/SDA or TX/RX pairs in a single package.
Architecturally, the PCA9306 uses a gate-drive scheme derived from VREF2 to bias the pass transistors, so the low-side rail (VREF1, 1.2V to 3.3V) is translated up to the high-side rail (VREF2, 1.8V to 5.5V). Because the device is a switch rather than a driver, the open-drain I2C pull-up resistors on each side set the logic levels, preserving multi-master arbitration and clock stretching behavior. Operating temperature range is -40C to +85C.
Typical applications include servers, routers and telecom switching equipment, personal computers, and industrial automation systems where a 1.8V/2.5V/3.3V MCU must communicate with 3.3V/5V I2C peripherals such as EEPROMs, sensors, and PMBus power supplies.
Design consideration: because RON of the pass switch appears in series with the bus, size the pull-up resistors to account for the added voltage drop at low-side logic-high levels; typical RON values are a few ohms, which is negligible for standard 100kbit/s to 400kbit/s I2C but should be verified for heavily loaded buses.
This page synthesizes distributor pricing data, verified drop-in alternatives, pinout details, and practical design notes not found in the manufacturer datasheet, giving engineers a single decision-ready reference.
Alternativas drop-in para PCA9306DCTR — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
PCA9306DCUR
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
PCA9306DCUTG4
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
TCA9406DCUR
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
PCA9306DCTR
✅ Drop-In✓ Em estoque
$0.35 / unidade
Ver ficha técnica →PCA9306DCTR Especificações
| Translator Type | Dual bidirectional voltage-level translator |
| Bus Interfaces | I2C, SMBus, PMBus, MDIO, UART, low-speed SDIO, GPIO |
| Number of Channels | 2 |
| VREF1 Input Voltage Range | 1.2 V to 3.3 V |
| VREF2 Input Voltage Range | 1.8 V to 5.5 V |
| Translation Range | 1.2 V to 5 V bidirectional |
| Direction Control | Not required (no direction pin) |
| Enable Input | Yes (EN, active-high) |
| Temperatura de operação | -40C to +85C |
| Encapsulamento | SOIC-8 (SM8, 3.90 mm width, SOT96-1) |
| Tipo de montagem | Surface Mount |
| Nível MSL | 1 (260C unlimited) |
| Status RoHS | Compliant |
| Lead Free | Yes |
| Part Life Cycle Code | Active |
Configuração de pinos do PCA9306DCTR
| Pino 1 | VREF1 — Low-voltage reference supply, 1.2V to 3.3V |
| Pino 2 | GND — Ground |
| Pino 3 | EN — Enable input, active high; low isolates both buses |
| Pino 4 | A2 — Channel 2 low-voltage side (e.g., SCL1) |
| Pino 5 | B2 — Channel 2 high-voltage side (e.g., SCL2) |
| Pino 6 | B1 — Channel 1 high-voltage side (e.g., SDA2) |
| Pino 7 | VREF2 — High-voltage reference supply, 1.8V to 5.5V |
| Pino 8 | A1 — Channel 1 low-voltage side (e.g., SDA1) |
Aplicações típicas
PCA9306DCTR é adequado para 6 aplicaçãos: Server I2C Management Bus, Router and Telecom Switching Equipment, Personal Computer Peripherals and SMBus, Industrial Automation Control, Low-Voltage Sensor Aggregation (1.2V to 1.8V), SD Card / Low-Speed SDIO Interface Level Shifting.
Server I2C Management Bus
Servers use a BMC (baseboard management controller) running at 1.8V or 3.3V to monitor PMBus power supplies, EEPROMs, and thermal sensors that may sit on 3.3V or 5V rails. The PCA9306DCTR fits this role because its pass-switch architecture preserves PMBus/SMBus clock stretching and multi-master arbitration, and its low RON adds negligible bus loading. Placed between the BMC SCL/SDA pins and the management bus, with 2.2k-10k pull-ups per rail, it enables 1.8V-to-3.3V translation while the EN pin allows the BMC to isolate the bus during hot-plug diagnostics. The dual-channel SOIC-8 covers both bus signals in one package, and the -40C to +85C range covers datacenter ambient conditions.
Recomendado
Router and Telecom Switching Equipment
Routers and telecom switching platforms routinely mix 1.2V or 1.8V ASIC/PHY control buses with legacy 3.3V or 5V board-management peripherals. The PCA9306DCTR's ability to translate from 1.2V upward without a direction pin makes it well suited to these MDIO and I2C-style control links, where the master dictates timing and the switch must not add skew. Because the device is passive, MDIO turnaround timing is unaffected, and the active-high EN lets the CPU gate the bus during board bring-up. Designers should size pull-ups to the bus capacitance (typical 1k-4.7k on dense backplanes) since the series RON contributes to the RC rise time; the industrial -40C to +85C rating covers telecom cabinets.
Recomendado
Personal Computer Peripherals and SMBus
PC motherboards and peripherals translate between a 1.8V embedded controller and the 3.3V SMBus that connects battery gauges, SPD EEPROMs, and thermal sensors. The PCA9306DCTR supports SMBus explicitly and its switch topology is compatible with the SMBus alert and ARA protocols, which buffered translators sometimes mishandle due to rise-time requirements. With VREF1 tied to the 1.8V EC rail and VREF2 tied to the 3.3V standby rail, both SDA and SCL are translated by the single 8-pin device. The MSL 1 rating (260C unlimited) suits standard consumer reflow profiles, and RoHS compliance meets global electronics regulations for consumer products.
Recomendado
Industrial Automation Control
Factory automation systems connect 1.8V-3.3V microcontrollers (such as the MC9S08 or Stellaris families on this site) to 5V-tolerant industrial I2C sensors, EEPROMs, and display drivers distributed along noisy cabinet wiring. The PCA9306DCTR translates from as low as 1.2V up to 5V, allowing modern low-voltage MCUs to drive legacy 5V buses without buffer-level incompatibilities. Its passive switch does not inject glitches on the bus, an advantage over active translators in environments with marginal grounding. The EN pin supports safe isolation during commissioning. Designers should keep bus capacitance below roughly 400 pF and choose pull-ups so rise times meet I2C standard-mode 100kbit/s or fast-mode 400kbit/s limits.
Recomendado
Low-Voltage Sensor Aggregation (1.2V to 1.8V)
Ultra-low-power designs using 1.2V-core sensors or ASICs often need to talk to a 1.8V system microcontroller. The PCA9306DCTR is one of few translators whose VREF1 range extends down to 1.2V, making it suitable for this narrow-margin, low-voltage pairing where most level shifters (which start at 1.4V-1.65V) cannot operate. Because both rails are low, pull-up selection matters greatly: at 1.2V, the 0.7V pass-transistor bias leaves limited noise margin, so recommend stronger pull-ups (2.2k) and short traces. The switch topology keeps quiescent loading minimal, extending battery life, and the EN pin lets the MCU power-gate the sensor bus entirely between sampling intervals.
Recomendado
SD Card / Low-Speed SDIO Interface Level Shifting
Low-speed SDIO interfaces in embedded systems sometimes pair a 1.8V host controller with 3.3V microSD cards or vice versa. The TI product page explicitly lists low-speed SDIO as a supported application for the PCA9306. Only the CMD and CLK two-signal pair is handled by one package, so DAT lines require additional channels or a second device - a key design consideration. Because SDIO is push-pull at higher speed than I2C, the translator is limited to low data rates where the series RON and bus capacitance do not distort edges; for high-speed SDR104-class interfaces an active directional translator is the better choice. Use 10k pull-ups on CMD and clock lines only where open-drain operation applies.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para PCA9306DCTR — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | PCA9306DCUR | PCA9306DCUTG4 | TCA9406DCUR | PCA9306DCTR (NXP) |
|---|---|---|---|---|---|
| Package | SOIC-8 (SM8) | SOIC-8 (SM8) - same | SOIC-8 (SM8) - same | SOIC-8 (SM8) - same | SOIC-8 (SM8) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors |
| Channels | 2 bidirectional | 2 bidirectional | 2 bidirectional | 2 bidirectional | 2 bidirectional |
| VREF1 Range | 1.2 V to 3.3 V | 1.2 V to 3.3 V | 1.2 V to 3.3 V | 1.08 V to 3.3 V (wider low end) | 1.2 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 | 1.65 V to 5.5 V | 1.8 V to 5.5 V |
| Direction Pin | Not required | Not required | Not required | Not required | Not required |
| Enable Pin | Yes (active-high EN) | Yes (active-high EN) | Yes (active-high EN) | Yes (active-high EN) | Yes (active-high EN) |
| Rise-Time Accelerators | No (passive switch) | No (passive switch) | No (passive switch) | Yes (integrated one-shot) | No (passive switch) |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Principais diferenciais
- Passive switch preserves I2C arbitration and clock stretching (vs TCA9406DCUR)
- Widest low-side range in family (vs PCA9306DCTR (NXP))
- Direction-free operation vs buffered translators (vs TXS0102)
Notas de projeto
Connect VREF2 to the higher rail through a pull-up resistor to VREF2, and tie the EN pin either to VREF2 (always-on) or to a GPIO/RC delay for controlled bus isolation. Place the device physically close to the low-voltage MCU to keep the sensitive SDA/SCL traces short, and provide 0.1uF decoupling on VREF2. Both bus sides need their own pull-up resistors to their respective rails; a single pull-up across the switch will not work because the switch drops voltage when conducting.
The pass switch conducts through an internal N-channel MOSFET with gate drive from VREF2, so the low-side logic-high is clamped near VREF1 plus a threshold-related offset. At VREF1 = 1.2V, noise margin is limited - verify the receiving threshold VIH of the 1.2V device and use stronger pull-ups (e.g., 2.2k) on the low side. Do not attempt hot-swap of VREF2 without EN low; disable the switch before powering rails asynchronously to avoid bus contention or back-powering through the switch.
Total bus rise time is governed by (pull-up resistance + RON) x (bus capacitance), split across both sides. For I2C fast-mode (400 kbit/s) with 100 pF per side, keep pull-ups around 2.2k-3.3k so rise time stays below the 300 ns specification limit. If heavy capacitive loading or long cables slow edges excessively, the TCA9406DCUR with integrated one-shot accelerators is a pin-compatible upgrade path that actively drives rising edges without PCB changes.
Informações de conformidade
RoHS compliant and lead-free per distributor data (Pbfree Code: Yes, RoHS Code: Yes). MSL 1 (260C unlimited). REACH, halogen-free, and conflict-minerals declarations not present in provided data.
