PCA9512D,118

Signal Buffers, Repeaters, Splitters Overview

The PCA9512D,118 is a hot swappable I2C and SMBus buffer manufactured by NXP Semiconductors. It provides bidirectional buffering for SDA and SCL lines to prevent signal corruption during live board insertion in multi-point backplane systems. The device features two dedicated supply voltage pins (VCC and VCC2) supporting level shifting between 3.3 V and 5 V systems within an operating range of 2.7 V to 5.5 V. It includes ∆V/∆t rise time accelerators with hardware disable capability via the ACC pin, supports clock stretching, and offers ESD protection exceeding 2000 V HBM. The component operates at frequencies up to 400 kHz and is available in SO8 packages.

Signal Buffers, Repeaters, Splitters Feature Summary

• Hot swappable design isolates card capacitance from the backplane to prevent bus corruption during insertion or removal.
• Dual supply architecture enables level translation between 3.3 V and 5 V systems while maintaining optimal noise margins.
• Integrated ∆V/∆t rise time accelerators enhance signal integrity on lightly loaded buses, with hardware disable functionality.

Signal Buffers, Repeaters, Splitters Applications

• cPCI, VME, and AdvancedTCA cards requiring safe insertion into operating backplanes.
• Multi-point backplane systems needing increased fanout and capacitance isolation.
• Level shifting interfaces between 3.3 V and 5 V I2C/SMBus domains.

Signal Buffers, Repeaters, Splitters Procurement Notes

Verify the ordering suffix '118' against current manufacturer documentation to confirm specific packaging details. Confirm that the SO8 package designation aligns with your PCB footprint requirements. Ensure compatibility with the specified -40 °C to +85 °C temperature range for your intended application environment before finalizing procurement.

Signal Buffers, Repeaters, Splitters Selection Notes

Select this component when designing systems requiring hot swapping capabilities for I/O cards without disrupting active bus operations. It is suitable for applications needing robust level translation between 3.3 V and 5 V logic levels. Consider the ACC pin configuration if system loading requires disabling the internal rise time accelerators to optimize performance for specific bus capacitance conditions.

Signal Buffers, Repeaters, Splitters Part Context

The PCA9512 belongs to the Philips/NXP PCA951x series of I2C bus buffers. Unlike the PCA9510 which lacks accelerators, or the PCA9513/14 which include current sources, the PCA9512 specifically targets dual-supply level shifting with configurable acceleration. It complements the PCA9511 by adding the ACC pin for accelerator control and dual VCC pins for improved noise margin in mixed-voltage environments.

Signal Buffers, Repeaters, Splitters Replacement Considerations

Publicly confirmed substitute part numbers are not provided in the source material. Designers should evaluate other members of the PCA951x family, such as the PCA9511 or PCA9513, based on specific feature requirements like accelerator control or current sourcing capabilities.

Signal Buffers, Repeaters, Splitters FAQ

How does the PCA9512 handle power-up sequencing?

The device enters an under-voltage lockout state until both VCC and VCC2 exceed 2.5 V. During initialization, it activates a 1 V precharge circuitry before enabling connection circuitry upon detecting a stop bit or bus idle condition.

What is the function of the ACC pin?

The ACC pin is a digital input that enables or disables the rise-time accelerators on all SDA and SCL pins. Driving it to VCC2 enables normal operation, while connecting it to GND turns off the accelerators for lightly loaded systems.

Can the PCA9512 be connected in series with other PCA951x devices?

Yes, the dynamic offset design allows connection to other PCA9510/11/12/13/14 devices in series or parallel. However, manufacturers generally recommend limiting series connections to two buffers to avoid excessive offset voltage accumulation.