PCA9509PGM,125

Signal Buffers, Repeaters, Splitters Overview

The PCA9509PGM,125 is a low-power level translating I2C-bus/SMBus repeater manufactured by NXP Semiconductors. It features two voltage supplies enabling interface between processor low-voltage buses and standard I2C or SMBus I/O. Port A operates from 0.8 V to 2.0 V, while Port B supports 2.3 V to 5.5 V. The device provides bidirectional buffering for SDA and SCL lines, supporting up to 400 pF capacitance on the higher voltage side. It accommodates Standard-mode and Fast-mode devices with clock frequencies up to 400 kHz. The component is housed in an XQFN8 package (SOT902-2) and operates within a temperature range of -40 °C to +85 °C.

Signal Buffers, Repeaters, Splitters Feature Summary

• Bidirectional buffer isolates capacitance and allows 400 pF on port B
• Voltage level translation from port A (0.8 V to 2.0 V) to port B (2.3 V to 5.5 V)
• No internal current source on A port to reduce current consumption for portable applications
• Active HIGH enable input disables current mirrors to reduce standby power

Signal Buffers, Repeaters, Splitters Applications

• Interface between processor low voltage 2-wire serial bus and standard I2C-bus or SMBus I/O
• Extending I2C-bus systems by providing bidirectional buffering for data and clock lines
• Applications requiring lock-up free operation and support for arbitration and clock stretching

Signal Buffers, Repeaters, Splitters Procurement Notes

Verify the ordering part number PCA9509PGM,125 against the specific datasheet revision required for the design. Confirm that the XQFN8 package dimensions match the PCB footprint constraints. Ensure the system design accounts for the 10 μs recovery time after enabling the device from standby mode to allow current mirrors to return to full current before resuming operation.

Signal Buffers, Repeaters, Splitters Selection Notes

Select the PCA9509PGM over the PCA9509 when lowest standby power consumption is critical, as this variant turns off current mirrors when disabled. Note that sufficient delay must be allowed after enabling the device before resuming communication. This model requires external pull-up resistors on Port A, unlike the PCA9509 which includes an internal current source. Verify that the application can tolerate the slightly longer startup time associated with the disabled current mirrors.

Signal Buffers, Repeaters, Splitters Part Context

The PCA9509PGM belongs to the PCA9509P family of low-power level translating repeaters. It shares functional characteristics with the TSSOP8 version (PCA9509PDP) but utilizes an XQFN8 leadless package. Both variants offer identical electrical performance regarding voltage translation and bus buffering capabilities. The primary distinction lies in the physical packaging and thermal dissipation properties inherent to the thin quad flat no-lead form factor.

Signal Buffers, Repeaters, Splitters Replacement Considerations

The PCA9509PDP serves as a direct functional replacement offering identical electrical specifications in a TSSOP8 package. For designs requiring an internal current source on Port A instead of an external resistor, the standard PCA9509 is the appropriate alternative. Ensure any substitute maintains compatibility with the 0.8 V to 2.0 V Port A range and 2.3 V to 5.5 V Port B range.