PCA9510(A), PCA9511(A), PCA9512(A), PCA9513(A), and PCA9514(A) device highlight

Key Features: Bi-Directional I2C Bus Buffering without Direction Control Up to 400kHz Operation on 400pF Buses Hot Swappable with Idle Detect Ideal for Multi-Point Distribution and Advanced TCA Applications "A" Versions have Increased Series Resistance for Improved Signal Integrity but Lower Drive

The PCA9510, PCA9510A, PCA9511, PCA9511A, PCA9513, PCA9513A, PCA9514, and PCA9514A are all hot swappable I2C and SMBus buffers that allow I/O card insertion into a live backplane without corrupting the clock or data buses. Control circuitry prevents the backplane I2C bus from being connected to the card I2C bus until a stop command or bus idle occurs on the backplane. When the connection is made, the bus buffers provide bi-directional buffering, keeping the backplane and card capacitances isolated.

These products incorporate:

• A digital ENABLE input pin, which enables the device when asserted HIGH and forces the device into a low current mode when asserted LOW
• An open-drain READY output pin, which indicates that the backplane and card sides are connected together (HIGH) or not (LOW).

Rise time accelerator circuitry allows the use of weaker DC pull-up currents while still meeting rise time requirements. The PCA9513(A) and PCA9514(A) rise time accelerator threshold has been moved from 0.6V to 0.8V to provide better noise margin. The rise time accelerator has been permanently disconnected on the PCA9510(A).

During insertion, the PCA9511(A) SDA and SCL lines are precharged to 1V to minimize the current required to charge the parasitic capacitance of the chip and prevent glitching the I2C bus. The PCA9513(A) and PCA9514(A) do not have this feature since the precharge is detrimental in some applications and the new resistive tip pins are more effective than precharge in some live insertion applications. The PCA9510(A) only has precharge on the bus side and not the card side.

The PCA9513(A) supplies a 92μA current source to the backplane SCLIN and SDAIN pins in lieu of using pull-up resistors for PICMG backplane applications. Including the current source into the device reduces parts count and provides for a consistent RC time constant as cards are removed and inserted into the backplane. As more cards are added (increasing the bus capacitance), the effective pull-up resistance decreases (more current sources in parallel) and maintains the RC value constant.

The PCA9512 and PCA9512A are a hot swappable I2C and SMBus buffers that allows I/O card insertion into a live backplane without corrupting the data and clock buses. The PCA9512(A) is similar to the PCA9511(A), but without the digital ENABLE input pin (pin #1) and the open-drain READY output pin (pin #5). The PCA9512(A) replaces the ENABLE pin with a dedicated supply voltage pin, V_CC2, for the card side, providing level shifting between 3.3V and 5V systems with optimal noise margin. Both the backplane and card may be powered with supply voltages ranging from 2.7V to 5.5V, with no constraints on which supply voltage is higher. The READY pin is replaced with a digital CMOS input pin, ACC, which enables or disables the rise-time accelerator currents for lightly loaded circuits.

The "A" versions of the PCA9510, PCA9511, PCA9512, PCA9513, and PCA9514 have higher series resistance outputs than their non-A versions. The benefit of the increased series resistance is improved signal integrity. The drawback, however, is reduced drive current. NXP Semiconductors offers both versions for different applications. The PCA9511A is specifically designed as an alternate source for the Linear Technology LTC4300A-1, and the PCA9512A is an alternate source for the LTC4300A-2.

• Detailed A versus non-A Version Information

Feature
Idle Detect
High Impedance SDA, SCL, and Control Pins When VCC = 0V
Rise Time Accelerator Circuitry on All SDA and SCL Lines
Rise Time Accelerator Circuitry Hardware Disable Pin for Lightly Loaded Systems
Rise Time Accelerator Threshold 0.8V vs. 0.6V Improves Noise Margin
Ready Open Drain Output
Two VCC Pins to Support 5V to 3.3V Level Translation with Improved Noise Margins
1V Precharge on All SDA and SCL Lines	In Only	In Only
92μA Current Source on SCLIN and SCAIN for PICMG Applications
Higher Drive Current
Higher Series Resistance

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	PCA9510		See PCA9510A replacement
	PCA9510A		Hot swappable I2C and SMBus buffer with higher series resistance
	PCA9511		See PCA9511A replacement
	PCA9511A		Hot swappable I2C and SMBus buffer with higher series resistance
	PCA9512		See PCA9512A replacement
	PCA9512A		Level shifting hot swappable I2C and SMBus buffer with higher series resistance
	PCA9513		See PCA9513A replacement
	PCA9513A		Hot swappable I2C and SMBus buffer with higher series resistance
	PCA9514		See PCA9514A replacement
	PCA9514A		Hot swappable I2C and SMBus buffer with higher series resistance

• Intelligent Platform Management Interface (IPMI) Explained

• I2C/SMBus Repeater/Hub/Extender Functions
• PCA Family