Mga Bus Repeater, Buffer at Extender

P82B715DRG4

P82B715DRG4 - 2-Bit 3-12V I2C Bus Extender | Texas Instruments

The Texas Instruments P82B715DRG4 is a 2-bit bidirectional I2C/SMBus buffer and cable extender operating from 3 V to 12 V at up to 400 kHz, with a 3 nF practical bus-wiring capacitance limit. The device is supplied in an 8-pin SOIC package and is designed for systems where cable length or bus capacitance prevents the standard I2C bus from driving distant nodes reliably. It uses unidirectional analog current amplification to increase the current-sink capability of the connected I2C controller and preserve operation of the bus protocol. An I2C bus extender is an interface IC that regenerates or buffers a two-wire serial bus. The I2C interface hierarchy consists of I2C and SMBus systems, serial bus extenders, bidirectional bus buffers, interface ICs, and semiconductors. Rather than adding another protocol controller, the P82B715 works with the existing clock and data lines, allowing a separated bus segment to communicate with the main bus while retaining standard operating modes. Key features include two independently buffered bidirectional channels, a 3 V to 12 V operating-power-supply range, 400 kHz bus operation, and support for a practical wiring capacitance of 3 nF. The manufacturer describes the device as a bipolar IC intended for I2C-bus and derivative systems. Its buffered Lx and Ly connections are designed to sink the larger currents needed when operating a high-capacitance bus at higher speed. The P82B715 architecture addresses voltage drop and effective bus capacitance rather than increasing the data rate beyond 400 kHz. Unidirectional analog current amplification gives the extender sufficient drive strength for longer wiring, while the buffered separation between the Sx/Sy and Lx/Ly sides helps isolate high-capacitance cable sections from the main bus. One reported propagation-delay value is 250 ns, making timing behavior a relevant consideration in long or heavily loaded installations. Typical uses include long industrial-control wiring, sensor and actuator networks, building-automation modules, embedded systems that need additional bus distance, and SMBus-derived equipment. The device is especially relevant when the calculated cable capacitance approaches the normal I2C limit but the system can retain 3 V to 12 V supply compatibility and 400 kHz operation. The primary design concern is confirming that the host bus can tolerate the extender's operating characteristics and that the separated cable section does not exceed the supported wiring capacitance. Supply decoupling, grounding, and the separation between controller-side and cable-side nets should follow the manufacturer datasheet guidance. Bus rise time and timing margins should be measured at the farthest node rather than inferred only from cable length. This product page consolidates the verified manufacturer function, package, voltage, frequency, capacitance, timing, and pricing information while distinguishing pin-compatible family alternatives. It also adds application-specific engineering guidance, comparison parameters, and replacement considerations that are not presented as a single block in the distributor listings.

PCA9517A

PCA9517A - Level-Translating I2C-Bus Repeater | NXP Semiconductors

The NXP PCA9517A is a CMOS level-translating I2C-bus repeater that shifts between low voltages down to 0.9 V on the A-side and 2.7 V to 5.5 V on the B-side, housed in a standard 8-pin SOIC package. It provides two-channel bidirectional buffering for both SDA and SCL while retaining all operating modes and features of the I2C-bus system during level shifts. A level-translating I2C-bus repeater is an interface IC that sits between two segments of an I2C or SMBus network, allowing devices operating from different supply rails - for example a 1.8 V microcontroller and a 3.3 V or 5 V peripheral - to communicate on the same bus. As a member of the I2C buffer/repeater/extender family within NXP's interface portfolio, it solves both voltage-domain mismatch and bus-capacitance limits in a single surface-mount device. Key features include voltage-level translation from 0.9 V up to 5.5 V, open-drain I2C-compatible I/O configuration, an active-high repeater-enable (EN) input for bus segmentation and power sequencing, and drivers that stay disabled until both VCC(A) (above 0.8 V) and VCC(B) (above 2.5 V) are present, preventing bus lock-up during power-up. SMBus compatibility extends its use into system-management designs. Technically, the A-side I/O and logic are powered by VCC(A) while the B-side is powered by VCC(B); the internal driver applies a static offset on the B-side, which means port B must not be connected to another device with rise-time accelerators (such as PCA9510/9511/9512/9513/9514/9515A/9516A or PCA9518). Pull-up resistors on both segments provide the logic-high levels, as with any standard open-drain I2C bus. Typical applications include interfacing 1.2 V to 1.8 V low-voltage SoCs with 3.3 V or 5 V sensor and EEPROM buses, extending I2C reach in telecom and networking backplanes, and managing multi-rail power supplies in industrial systems. Designers should keep EN changes limited to bus-idle states to avoid corrupting in-progress transfers, and verify that chained buffer topologies follow the NXP datasheet restrictions. This page synthesizes verified datasheet facts, cross-brand drop-in options such as TI's TCA9517, and practical design notes not found in the manufacturer datasheet alone.