Part Number: PCA9306DQER

Manufacturer: Texas Instruments


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Technical Specifications of PCA9306DQER

Datasheet  PCA9306DQER datasheet
Category Integrated Circuits (ICs)
Family Logic – Translators, Level Shifters
Manufacturer Texas Instruments
Packaging Tape & Reel (TR)
Part Status Active
Translator Type Voltage Level
Channel Type Bidirectional
Number of Circuits 1
Channels per Circuit 2
Voltage – VCCA 1.2 V ~ 3.3 V
Voltage – VCCB 1.8 V ~ 5.5 V
Input Signal
Output Signal
Output Type Open Drain, Push-Pull
Data Rate
Operating Temperature -40°C ~ 85°C (TA)
Features Auto-Direction Sensing
Mounting Type Surface Mount
Package / Case 8-XFDFN
Supplier Device Package 8-X2SON (1.4×1.0)

PCA9306DQER Description

I2C and SMBus use the PCA9306 two-way voltage-level translator. 1.2 V to 3.3 V VREF1 and 1.8 V to 5.5 V VREF2 are supported. Enable (EN) input. PCA9306 can convert voltages between 1.2 V and 5 V in any direction without a direction pin. The switch features low ON-state resistance (RON). This allows fast connectivity. EN high activates the translator switch. This links the SCL1 and SDA1 I/O to the SCL2 and SDA2 ports, allowing data to flow in both directions. EN is low, the translator switch is off, and the ports are high impedance. PCA9306 may alter voltage and more. It can separate 100-kHz and 400-kHz buses. EN pin disconnects the slower bus during a fast-mode connection.

PCA9306DQER Features

  • 2-Bit SDA/SCL translator for mixed-mode I2C applications.
  • I’m 2C/SMBus compatible.
  • The propagation latency must be shorter than 1.5 ns and support standard-mode and fast-mode I2C devices and many controllers.
  • Voltage translation in both directions without a direction pin.
  • The 3.5-ON-state resistance between input and output ports reduces signal distortion.
  • Open-drain I2C I/O (SCL1, SDA1, SCL2, and SDA2).
  • 5-V-tolerant mixed-mode I2C input/output ports.
  • SCL1, SDA1, and SCL2 have high impedance when EN is low.
  • Low EN does not lock up the process.
  • Flow-through pinout simplifies PCB routing.
  • Latch-up performance exceeds 100 mA per JESD 78, class II.

Detailed Description

The PCA9306 is a voltage-level translator for I2C and SMBus that works in both directions. It doesn’t need a direction pin and has an enable (EN) input. It also has a switch-on input (EN). VREF1 can be powered by a voltage between 1.2 V and 3.3 V, while VREF2 can be powered by a voltage between 1.8 V and 5.5 V. Also, the PCA9306 component can run two separate buses, one with a frequency of 400 kHz and the other with a frequency of 100 kHz. If the two buses are running at different speeds, the EN pin needs to be used to disconnect the 100-kHz bus from the 400-kHz main bus. When the two buses are running at different speeds, this is necessary.

Because the level shifter adds delays, the system’s maximum operating frequency may be lower than 400 kHz, even if the controller works at 400 kHz, which is the higher frequency. The capacitance of an I2C bus, which can’t be more than 400 pF, determines how many devices can be connected to it. The capacitive load on both sides of the PCA9306 device must be included when determining the system’s total load. This is done to ensure that both sides’ capacitance is less than 400 pF when added together. Voltage or propagation delay changes very little from one output to the next, and the SDA and SCL channels of the PCA9306 device, which are both parts of the same device, have the same electrical properties.

Since the switch can be built symmetrically, it has a number of advantages over voltage-translation systems that use discrete transistors. The translator protects electronics less resistant to electrostatic discharge (ESD) better and also protects electronics that work at lower voltages (ESD).

Definition of threshold voltage

When the document talks about the NFET between VREF1 and VREF2, it talks about a voltage called Vth, the threshold voltage. This voltage is talked about more than once in this document. When measured at room temperature, Vth is about 0.6 V.

● Disconnecting an I2C target from the Main I2C Bus Using the EN Pin

PCA9306 can work as a switch, which means that one side of the device can be cut off from the main I2C bus. This could be useful in a number of different situations. One example is when some devices on an I2C bus only support the fast mode of operation (400 kHz), and other devices on the bus support both the fast mode and the fast mode plus (1 MHz).

● The controller on Side 1 or Side 2 of Device

I2C and SMBus are examples of bidirectional protocols, meaning that devices connected to the bus can send and receive data. PCA9306 was made so that signals could be sent from either side. This means the controller could be placed on either the left or right side of the device. The fact that signals could be sent from either side made this possible.

● LDO and PCA9306 Concerns

The bias current from VREF2 to VREF1 can sometimes cause a low-dropout regulator (LDO) to lose its regulation. The bias current will charge VREF1’s capacitance if the LDO can’t drain it (both external and parasitic). This raises the VREF1 node voltage. If VREF1 node devices do not back the biasing body or clamping diodes, the VREF1 voltage will stabilize when the pass FET’s Vgs equals Vth. If electricity can’t flow elsewhere, this happens. VREF1 is VCC2 minus Vth. LDO targets and controllers now view VCC2 minus Vth. They’ll be damaged if these targets or controllers can’t manage the higher voltage.

Application Information

● General Applications of I2C

Pullup resistors maintain logic-high levels on the translator bus. The system determines how many pullup resistors each repeater site needs. It supports standard-mode and fast-mode I2C devices. It supports SMBus devices. A generic I2C system that supports standard-mode devices and numerous controllers can set 3 milliamps. High termination currents can be advantageous.

The clamp will be ON if either SDA1 or SDA2 port is low, forming a low-resistance connection. When SDA2 is high, VREF1 limits the SDA1 port’s voltage. The pull-up resistors drive the SDA2 port to VDPU when the SDA1 port is high. This function lets users smoothly switch between higher and lower voltages without direct control. SDA1-SDA2 and SCL1-SCL2 channels act similarly.

Power Supply Recommendations

The VREF1 pin on the PCA9306 device can be linked directly to a power supply to provide electricity. A resistor of value 200 k must be used to connect the VREF2 pin to the power source provided by the VDPU. If there is not a resistor with a high impedance placed between VREF2 and VDPU, then the device will draw an excessive amount of current and will not function reliably. It is also important to note that for the PCA9306 to support voltage translation, the EN and VREF2 pins need to be connected to form a short, and then a high-impedance resistor must be used connected between those two pins and VDPU.


Guidelines for Layout When making the layout for the PCA9306 device, it’s important to follow standard practices for printed circuit board (PCB) layout. But high-speed data transfer difficulties don’t affect I2C signal speeds. such as matched impedances and differential pairs. When making a PCB layout, it is recommended that you don’t use right angles in signal traces, spread out signal traces as they leave an integrated circuit (IC), and use wider trace widths to carry more current than power and ground traces, usually do.

All of these best practices should be followed. It is recommended that the filter capacitor with 100 pF be positioned as close to VREF2 as is physically possible. It is also possible to use a larger decoupling capacitor. However, this makes the PCA9306 device take longer to turn on and off because the time constant for combining the two capacitors and the 200-k resistor is longer.


In summary, the Texas Instruments PCA9306DQER level translator is a reliable part that ensures electronic circuits get the right voltage when turned on. It is easy to handle and use because it can work in a wide range of temperatures and comes on a tape and reel. This device has a wide range of operating supply voltages, so it can be used in many different situations. If you want to learn more about the PCA9306DQER or order one, please don’t hesitate to contact us at ICRFQ. We’re proud of the fact that we sell high-quality electronic parts at low prices.

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