Overview
The PCA9512AD, produced by NXP Semiconductors (formerly Freescale Semiconductor), is a hot swappable I²C-bus and SMBus buffer designed to facilitate the insertion and removal of I/O cards into a live backplane without corrupting the data and clock buses. This component is crucial for systems that require dynamic card insertion and removal, such as AdvancedTCA cards and other multipoint backplane systems.
Key Specifications
| Specification | Details |
|---|---|
| Function | Hot swappable I²C-bus and SMBus buffer |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Level Shifting | Between 3.3 V and 5 V systems with improved noise margins |
| Bus Compatibility | I²C-bus Standard mode, I²C-bus Fast mode, and SMBus standards |
| Rise Time Accelerator | Circuitry to meet rise time requirements with weaker DC pull-up currents |
| Precharge Voltage | SDAn and SCLn pins precharged to 1 V during insertion |
| Idle Detect | Control circuitry prevents backplane connection until a stop bit or bus idle occurs |
| High-Impedance Pins | SDAn and SCLn pins in high-impedance state for VCC = 0 V |
Key Features
- Bidirectional Buffering: The PCA9512AD provides bidirectional buffering for SDA and SCL lines, increasing fan-out and preventing data corruption during live board insertion and removal.
- Level Shifting: Supports level shifting between 3.3 V and 5 V systems with improved noise margins.
- Rise Time Accelerator: Includes circuitry to meet rise time requirements even with weaker DC pull-up currents, and a digital input pin to enable or disable these accelerators.
- Hot Swappable: Allows I/O card insertion into a live backplane without data and clock bus corruption.
- Precharged Pins: SDAn and SCLn pins are precharged to 1 V during insertion to minimize the current required to charge parasitic capacitance.
Applications
It is commonly used in AdvancedTCA cards, multipoint backplane systems, and various industrial and automotive applications.
Q & A
- What is the primary function of the PCA9512AD?
The PCA9512AD is a hot swappable I²C-bus and SMBus buffer that allows I/O card insertion into a live backplane without corrupting the data and clock buses.
- What is the supply voltage range for the PCA9512AD?
The supply voltage range is from 2.7 V to 5.5 V.
- Does the PCA9512AD support level shifting between different voltage systems?
Yes, it supports level shifting between 3.3 V and 5 V systems with improved noise margins.
- What bus standards is the PCA9512AD compatible with?
It is compatible with I²C-bus Standard mode, I²C-bus Fast mode, and SMBus standards.
- How does the rise time accelerator circuitry work?
The rise time accelerator circuitry allows the use of weaker DC pull-up currents while still meeting rise time requirements, and it can be enabled or disabled via a digital input pin.
- What is the purpose of precharging the SDAn and SCLn pins during insertion?
The SDAn and SCLn pins are precharged to 1 V to minimize the current required to charge the parasitic capacitance of the chip.
- How does the PCA9512AD prevent bus contention during card insertion?
Control circuitry prevents the backplane from being connected to the card until a stop bit or bus idle occurs on the backplane without bus contention on the card.
- Can the PCA9512AD be used in series or parallel with other similar devices?
Yes, the incremental offset design allows it to be connected to another PCA9510A/11A/12A/13A/14A device in series or in parallel.
- What are some common applications for the PCA9512AD?
It is commonly used in AdvancedTCA cards, multipoint backplane systems, and various industrial and automotive applications.
- Is the PCA9512AD suitable for hot swappable I/O cards in live systems?
Yes, it is specifically designed for hot swappable applications, ensuring data integrity during card insertion and removal.
