PCA9509D,118

Signal Buffers, Repeaters, Splitters Overview

The PCA9509D,118 is a level translating I2C-bus/SMBus repeater manufactured by NXP Semiconductors. It enables processor low voltage 2-wire serial bus to interface with standard I2C-bus or SMBus I/O devices. The device provides bidirectional buffering for both data (SDA) and clock (SCL) lines, supporting Standard-mode and Fast-mode operation up to 400 kHz. Port A operates at voltages from 1.35 V to VCC(B) - 1.0 V, while Port B supports 3.0 V to 5.5 V. It features an active HIGH enable input, open-drain inputs/outputs, and powered-off high-impedance pins. The component is housed in an SO8 plastic small outline package.

Signal Buffers, Repeaters, Splitters Feature Summary

• Bidirectional buffer isolates capacitance and allows 400 pF on port B
• Voltage level translation from port A to port B without external pull-up resistors on lower voltage port A
• Lock-up free operation with current sensing mechanism on port A
• Supports arbitration and clock stretching across the repeater

Signal Buffers, Repeaters, Splitters Applications

• Interface between processor low voltage I2C-bus and standard I2C-bus or SMBus I/O
• Extension of I2C-bus by providing bidirectional buffering for SDA and SCL lines
• Connecting 1.35 V CPU buses to 3.3 V or 5 V master devices

Signal Buffers, Repeaters, Splitters Procurement Notes

Verify the specific ordering suffix

Signal Buffers, Repeaters, Splitters Selection Notes

Select this part when interfacing low voltage processors (down to 1.35 V) with standard 3.3 V or 5 V I2C/SMBus systems. Ensure VCC(A) remains above 0.8 V and VCC(B) above 2.5 V for driver enablement. Avoid ground offsets greater than 50 mV between Port A and connected devices to prevent signal recognition failures. Use PCA9509A if Port A voltage drops below 1.35 V.

Signal Buffers, Repeaters, Splitters Part Context

The PCA9509D,118 belongs to the PCA9509 series of level translating repeaters. The 'D' suffix indicates the SO8 package variant, while ',118' denotes the reel packing method. This component is part of NXP's portfolio for managing mixed-voltage I2C environments, distinct from the PCA9509A which supports lower voltage ranges on Port A.

Signal Buffers, Repeaters, Splitters Replacement Considerations

PCA9509A is specified as a drop-in replacement if Port A VCC(A) is less than 1.35 V or Port B VCC(B) is less than 3.0 V.