摘要

P82B96 是一款高度通用的雙極積體電路 (IC)，旨在促進標準 I2C 匯流排訊號與具有不同電壓和電流位準的其他匯流排配置之間的非鎖存雙向邏輯介面。

This IC is notable for its ability to isolate bus capacitance, which significantly extends the communication distance and enhances noise immunity, making it an essential component in various electronic applications, including industrial automation, automotive systems, and smart home technologies. One of the P82B96’s standout features is its support for bidirectional data transfer of I2C-bus signals, allowing up to 400 pF on the Sx/Sy side and 4000 pF on the Tx/Ty side. This enables the IC to support I2C-bus operations at 400 kHz over distances of at least 20 meters of wire, making it ideal for long-distance communication setups. The IC also features a wide supply voltage range of 2 V to 15 V, independent I2C logic levels on the Sx/Sy side, and robust ESD protection, enhancing its durability and reliability in various environments. The P82B96 is widely used for interfacing between I2C buses operating at different logic levels, such as 5 V and 3 V or 15 V, and for opto-electrical isolation to maintain signal integrity in electrically noisy environments. Its ability to convert I2C SDA or SCL signals to multi-drop differential bus hardware further expands its application scope, particularly in systems requiring high noise immunity and extended communication distances. The IC’s latch-up-free design, various packaging options, and low power supply current add to its versatility and ease of integration into diverse electronic systems. However, the P82B96 is not without limitations. Engineers must ensure that the bus capacitance does not exceed specified limits, and proper logic level conversion is maintained to avoid communication errors. Despite these considerations, the P82B96 remains a critical component in modern electronic designs, offering significant advantages in terms of communication range, noise immunity, and flexibility in interfacing different bus configurations.

特徵

The P82B96 is a versatile bipolar integrated circuit (IC) that facilitates non-latching, bidirectional logic interface between the standard I2C-bus and various other bus configurations

. This IC can interface I2C-bus logic signals to similar buses that have differing voltage and current levels, enhancing its adaptability to diverse applications. One of the significant features of the P82B96 is its ability to support bidirectional data transfer of I2C-bus signals. It isolates capacitance, allowing 400 pF on the Sx/Sy side and 4000 pF on the Tx/Ty side. The Tx/Ty outputs boast a 60 mA sink capability, which is useful for driving low impedance or high capacitive buses. The IC is capable of operating at 400 kHz over distances of at least 20 meters of wire. Furthermore, it has a wide supply voltage range of 2 V to 15 V, with I2C logic levels on the Sx/Sy side being independent of the supply voltage. Additionally, the P82B96 splits the I2C signal into pairs of forward/reverse Tx/Rx and Ty/Ry signals, which are ideal for interfacing with opto-electrical isolators and similar devices requiring unidirectional input and output signal paths. The IC also features low power supply current and provides robust ESD protection that exceeds 3500 V HBM per JESD22-A114, 250 V for DIP package / 400 V for SO package MM per JESD22-A115, and 1000 V CDM per JESD22-C101. In terms of reliability, the P82B96 is latch-up free due to its bipolar process, which avoids latching structures. The IC is available in various packages, including DIP, SO, and TSSOP, making it adaptable to different design requirements. Typical applications of the P82B96 include interfacing between I2C buses operating at different logic levels (e.g., 5 V and 3 V or 15 V), interfacing between I2C and SMB (350 µA) bus standard, and simple conversion of I2C SDA or SCL signals to multi-drop differential bus hardware. It is also used to interface with opto-couplers to provide opto-isolation between I2C-bus nodes up to 400 kHz.

功能说明

The P82B96 is a versatile bipolar IC designed to provide a non-latching, bidirectional logic interface between a standard I2C-bus and various other bus configurations with differing voltage and current levels

. It allows the I2C-bus logic signals to interface seamlessly with buses that operate at voltages ranging from 2V to 15V, making it compatible with a wide array of logic devices. This IC is particularly useful for interfacing with the 350 µA SMBus, 3.3V logic devices, and systems operating at 15V levels. Additionally, it can handle low impedance lines to improve noise immunity over longer bus lengths. The P82B96 achieves this without imposing any restrictions on the normal I2C-bus protocols or clock speed, thereby adding minimal loading to the I2C-bus node. This feature ensures that the loadings of the new bus or remote I2C-bus nodes are not transmitted or transformed to the local node. A notable feature of the P82B96 is its capability to isolate capacitance, allowing up to 400 pF on the Sx/Sy side and up to 4000 pF on the Tx/Ty side. This isolation significantly enhances the performance of the bus by enabling long-distance communication of up to 20 meters at 400 kHz. The Tx/Ty outputs are designed with a 60 mA sink capability, which is ideal for driving low impedance or high capacitive buses. The P82B96 also facilitates the transmission of SDA and SCL signals via balanced transmission lines (such as twisted pairs) or through galvanic isolation (like opto-coupling). This is possible because separate directional Tx and Rx signals are provided. The Tx and Rx signals can be directly connected without causing latching, thus creating an alternative bidirectional signal line with I2C-bus properties. Moreover, the part numbers for the P82B96 series include P82B96DP and P82B96TD, which offer a quick reference to the different documentation and design files available for this IC.

應用領域

The P82B96 IC is a versatile bipolar device that supports bidirectional data transfer between an I2C bus and various other bus configurations with different voltage and current levels. This makes it an essential component in numerous electronic design applications. One of the primary applications of the P82B96 is its ability to interface between I2C buses operating at different logic levels, such as 2 V and 15 V

. This feature allows it to connect devices with varying voltage requirements without compromising performance. For instance, the P82B96 can be used to interface the standard 5V I2C buses with lower voltage 3.3V logic devices, or even higher voltage 15V levels, enhancing its versatility in mixed-voltage environments. Another significant application is its use in extending the communication distance of I2C buses. By allowing bus capacitance of up to 4000 pF on the transmission side, the P82B96 can support 400-kHz fast I2C bus operation over at least 20 meters of wire, making it ideal for long-distance communication setups. This is particularly useful in industrial automation and control systems where sensors and controllers are often placed far apart. The P82B96 also finds application in environments that require opto-electrical isolation. It interfaces with opto-couplers to provide opto-isolation between I2C-bus nodes, which is crucial for maintaining signal integrity and preventing noise interference in electrically noisy environments. This makes it suitable for use in automotive systems, industrial automation, and other settings where signal reliability is paramount. Furthermore, the P82B96 IC can be employed in the simple conversion of I2C bus SDA or SCL signals to multi-drop differential bus hardware. This is achieved via compatible devices like the PCA82C250, which facilitates the transmission of I2C signals over longer distances with improved noise immunity. In practical applications, the P82B96 has been used to extend I2C communication distances in systems involving multiple sensors. For example, it can connect temperature/humidity sensors, soil moisture sensors, and light sensors to a central controller like a Raspberry Pi, thereby enabling robust data acquisition over extended distances.

引脚配置

The P82B96 IC features a flexible pin configuration designed to facilitate bidirectional data transfer of I2C-bus signals. The device allows for isolation of capacitance, enabling up to 400 pF on the Sx/Sy side and up to 4000 pF on the Tx/Ty side, providing robust performance even with high capacitive buses

. The Tx/Ty outputs are capable of sinking 60 mA, making them suitable for driving low-impedance loads.

引脚说明

Sx/Sy Pins

The Sx and Sy pins on the P82B96 can function as either the Serial Data (SDA) or Serial Clock (SCL) lines when connected to the corresponding Rx/Tx and Ry/Ty pins

. These pins must not be connected to each other on the same node, as this configuration is not supported and could lead to noise susceptibility and operational issues.

Tx/Rx and Ty/Ry Pins

The Tx/Rx and Ty/Ry pins facilitate bidirectional signal lines with I2C properties, allowing for straightforward communication design. These pins enable a star or multi-point configuration where multiple P82B96 devices share the same Tx/Rx and Ty/Ry nodes on a common bus, interfacing with line-card slave devices

. However, similar buffers that rely on special logic thresholds should not be connected to the Sx/Sy side of the P82B96, as they would not recognize the buffered low signals correctly.

電源

The P82B96 operates over a supply voltage range of 2 V to 15 V. The I2C-bus logic levels on the Sx/Sy side are independent of the supply voltage, providing flexibility in various application scenarios

.

附加功能

The P82B96 is designed with ESD protection, exceeding 3500 V HBM per JESD22-A114, 250 V for DIP packages, 400 V for SO packages MM per JESD22-A115, and 1000 V CDM per JESD22-C101, ensuring durability and reliability in harsh environments

. The device also boasts low power supply current, making it energy-efficient and suitable for a wide range of applications.

设计考虑因素

When integrating the P82B96 IC into an electronic design, several important factors must be considered to ensure optimal performance and compatibility with other components.

电气特性

The P82B96 is designed to operate within a power-supply voltage range of 2 V to 15 V, which allows it to interface between I2C buses operating at different logic levels within this range. This feature is particularly useful in systems requiring different voltage domains to communicate seamlessly without additional level-shifting components

.

Bus Capacitance and Cable Length

One of the standout features of the P82B96 is its ability to support longer cable lengths by allowing a bus capacitance of up to 400 pF on the main side (Sx/Sy) and up to 4000 pF on the transmission side (Tx/Ty). This capability significantly improves the restrictions on the number of I2C devices in a system due to capacitance and physical separation, thus allowing more devices per I2C bus and greater flexibility in system layout

.

Isolation and Signal Integrity

The P82B96 provides galvanic isolation, which can be achieved using optocouplers, or it can use balanced transmission lines such as twisted pairs. The IC splits I2C bus signals into pairs of forward (Tx/Ty) and reverse (Rx/Ry) signals, which allows for unidirectional signal paths and minimizes the risk of signal interference. This design approach helps in maintaining signal integrity over longer distances and in electrically noisy environments

.

Bidirectional Communication

The IC is designed to handle bidirectional I2C signals without a direction control pin, relying instead on slightly different logic low-voltage levels at the Sx/Sy pins. This unique design prevents bus latching and allows for robust bidirectional communication. However, it is crucial to ensure that two or more Sx or Sy I/Os are not connected to each other on the same node, as the P82B96 does not support this configuration

.

应用灵活性

The P82B96 is suitable for applications that require a high-current sink capability for driving low-impedance or high-capacitive buses. It supports fast I2C bus operation up to 400 kHz over at least 20 meters of wire, making it a versatile component for various industrial and automotive applications

. By carefully considering these design aspects, engineers can effectively leverage the capabilities of the P82B96 to enhance the performance and reliability of their I2C communication systems.

优势

One of the main advantages of the P82B96 IC is its ability to support longer cables and traces, which allows for the inclusion of more devices on an I2C bus by isolating bus capacitance. This isolation means that the total loading of the new bus or remote I2C nodes does not affect other I2C buses or nodes, thus improving the system’s capacity and physical separation between devices

. The P82B96 IC also provides the capability for galvanic isolation through optocoupling or balanced transmission lines, such as twisted pairs. This is achieved because the device offers separate directional Tx and Rx signals, which can be connected directly to create a bidirectional signal line with I2C properties without causing bus latching. Additionally, the device allows for a simple communication design, which can save both design time and costs. The Tx and Rx signals, as well as the Ty and Ry signals, can be connected together to provide a bidirectional signal line with open-drain driver characteristics. This flexibility in design helps in maintaining system efficiency and reliability. Another significant advantage is the ability of the P82B96 IC to interface I2C-bus logic signals to various buses with different voltage and current levels, including the 350 µA SMBus and logic devices operating at 3.3 V or 15 V. This capability enhances noise immunity on longer bus lengths without imposing restrictions on the normal I2C-bus protocols or clock speeds. The IC achieves this with minimal loading on the I2C-bus node, ensuring that the loading of the new or remote I2C-bus nodes is not transmitted back to the local node. This feature effectively eliminates restrictions on the number of I2C-bus devices within a system or the physical separation between them.

与同类集成电路的比较

The P82B96 stands out among similar integrated circuits due to its versatility and advanced features designed for I²C-bus systems. One notable comparison is with the older 82B715 device. The 82B715 primarily functions to increase bus current by a factor of ten but does not enhance the threshold noise immunity, which remains at the same levels

. On the other hand, the P82B96 offers bidirectional data transfer and isolates capacitance, allowing up to 4000 pF on the Tx/Ty side, which is significantly higher compared to the limitations of the 82B715. Additionally, the P82B96 has advanced capabilities to split the bus into separate Rx and Tx channels, which can be particularly useful for achieving longer range communications by employing differential drivers and receivers such as RS422/485 on these lines. This makes the P82B96 more adaptable for complex bus configurations and longer cable lengths without compromising the integrity of the signal. Another aspect where the P82B96 excels is its ability to interface I²C-bus logic signals to similar buses with different voltage and current levels, such as interfacing with 3.3 V logic devices or 15 V levels, and driving low-impedance or high-capacitive buses up to 60 mA. This flexibility is not found in the 82B715, which is limited in its application scope. Furthermore, the P82B96 supports 400 kHz operation over at least 20 meters of wire, ensuring robust performance in extended bus configurations. This is complemented by its low power supply current and extensive ESD protection, making it a reliable choice for diverse and demanding environments.

局限性

The P82B96 integrated circuit (IC) is designed to enhance the communication capabilities of I2C buses by isolating bus capacitance and supporting longer cables or traces. However, there are some limitations and considerations when integrating this device into a system. First, although the P82B96 facilitates longer communication distances and supports more devices per I2C bus, it is crucial to ensure that the total capacitance does not exceed specified limits. On the main side (Sx/Sy), the bus capacitance must not exceed 400 pF, and on the transmission side (Tx/Ty), it must not exceed 4000 pF

. Exceeding these capacitance limits can degrade signal integrity and lead to communication errors. Second, while the IC can interface between I2C buses operating at different logic levels ranging from 2 V to 15 V, care must be taken when matching these levels to avoid any potential mismatches that could result in unreliable data transmission. Proper logic level conversion must be ensured for effective communication across different voltage domains. Additionally, the P82B96 employs open-drain drivers to provide bidirectional signal lines for both the forward (Tx/Ty) and reverse (Rx/Ry) communication paths. This configuration requires external pull-up resistors to function correctly, and incorrect resistor values can impact the overall performance of the bus, such as causing slower rise times or increased power consumption. The IC also offers the capability to use galvanic isolation (optocoupling) or balanced transmission lines (twisted pairs), which can improve communication robustness in noisy environments. However, implementing these features may introduce additional complexity and cost into the system design, which must be considered during the planning phase. Finally, despite the IC’s capability to support fast I2C bus speeds up to 400 kHz, system designers must ensure that other components on the I2C bus can operate reliably at these speeds. Incompatibilities in clock speed among different components can lead to communication failures or data corruption.

Real-World Examples

The P82B96 IC is utilized in a variety of real-world applications due to its versatility and robustness. One of its primary uses is in extending the range of I2C buses by splitting the bus into separate receive (Rx) and transmit (Tx) channels, allowing for longer cable runs and more devices to be connected without degradation of the signal quality

. For instance, in automotive systems, the P82B96 can enable reliable communication between various sensors and control units spread across the vehicle, ensuring data integrity and minimal signal loss over long distances. In industrial automation, the P82B96 is often used to facilitate communication between different pieces of machinery and control systems. The device’s capability to isolate bus capacitance significantly improves the number of devices and the physical distance over which they can operate. This makes it ideal for factory settings where long cable runs and numerous interconnected devices are common. Moreover, the P82B96 finds applications in smart home and building automation systems. It allows for the integration of various subsystems such as lighting, heating, and security by ensuring that signals can travel across different parts of a building without interference or loss. The IC’s support for opto-isolation also enhances the safety and reliability of these systems by preventing potential electrical faults from propagating across the network. Another practical example is in the use of the P82B96 in smart meters and connected devices, where it ensures robust data transmission over longer distances within the power grid infrastructure. The IC’s ability to interface between I2C buses operating at different logic levels (e.g., 5V and 3V or 15V) further enhances its adaptability to various applications.