Overview
The P82B715, produced by Texas Instruments, is a dual bidirectional I2C bus extender designed to enhance the capabilities of I2C bus systems. This device buffers both the serial data (SDA) and serial clock (SCL) signals, allowing for the extension of I2C bus communication over longer distances while retaining all the operating modes and features of the I2C system. It is particularly useful in applications where the I2C bus capacitance limit restricts practical communication distances to just a few meters.
Key Specifications
| Parameter | Description |
|---|---|
| Operating Power-Supply Voltage Range | 3 V to 12 V |
| Bus Capacitance | 400 pF on Main I2C Bus (Sx/Sy Side), 3000 pF on Transmission Side (Lx/Ly Side) |
| Buffer Type | Dual Bidirectional Unity-Voltage-Gain Buffer |
| Clock Speeds | Up to 100 kHz and 400 kHz |
| ESD Protection | Exceeds 2500 V HBM, 400 V MM, and 1000 V CDM |
| Latch-up Performance | Exceeds 100 mA per JESD 78, Class II |
| Package Options | SOIC (8), PDIP (8) |
| Thermal Resistance | Junction-to-ambient: 105.3°C/W (SOIC), 48.9°C/W (PDIP) |
Key Features
- Supports bidirectional data transfer of I2C bus signals.
- Allows for the extension of I2C bus communication over long cables (up to 50 meters) and higher capacitance loads.
- Drives 10× lower-impedance bus wiring for improved noise immunity.
- Multi-drop distribution of I2C signals using low-cost twisted-pair cables.
- Internal current amplification to increase the current sink capability of I2C chips.
- Internal diodes for ESD protection and logic signal swing limitation.
- Compatible with all logic signal drivers, including TTL.
Applications
- HDMI DDC (Display Data Channel).
- Long I2C communications in various systems.
- Industrial communications where extended bus lengths are necessary.
- Analog radial IPMB (Intelligent Platform Management Bus) shelf applications.
Q & A
- What is the operating power-supply voltage range of the P82B715?
The operating power-supply voltage range is from 3 V to 12 V.
- How does the P82B715 extend the I2C bus communication distance?
The P82B715 extends the I2C bus communication distance by buffering both the SDA and SCL signals, allowing for higher capacitance loads and longer cables.
- What is the maximum bus capacitance supported by the P82B715?
The P82B715 supports up to 400 pF on the main I2C bus and up to 3000 pF on the transmission side.
- Does the P82B715 require external directional control?
No, the P82B715 does not require external directional control; it operates as a dual bidirectional unity-voltage-gain buffer.
- What are the ESD protection levels of the P82B715?
The P82B715 exceeds 2500 V HBM, 400 V MM, and 1000 V CDM for ESD protection.
- Can the P82B715 be used in multi-drop configurations?
- How does the P82B715 handle current amplification?
The P82B715 amplifies the current sink capability of I2C chips by sinking ten times the current into the buffered bus to drive it low.
- Is the P82B715 compatible with TTL logic signal drivers?
- What are the typical applications of the P82B715?
The P82B715 is typically used in HDMI DDC, long I2C communications, industrial communications, and analog radial IPMB shelf applications.
- How should the pullup resistors be calculated for the P82B715?
The pullup resistors should be calculated to achieve a time constant of less than 1 μs for each bus section, considering the sum of device and wiring capacitances.
