PCA9545D/G-T

Specialized Overview

The PCA9545D/G-T is a multiplexing switch IC manufactured by NXP Semiconductors, designed for I2C and SMBus bus systems. It features a 2 x 4:1 configuration, allowing four independent channels to be selectively connected to two common buses. The device operates within a supply voltage range of 2.3 V to 5.5 V and supports data rates up to 400 kHz. Key electrical parameters include a maximum on-resistance of 24 Ohms, a propagation delay of 300 ns, and a power dissipation of 400 mW. It functions within an industrial temperature range of -40°C to +85°C and is housed in a 20-pin SOIC package.

Specialized Feature Summary

• Provides bidirectional translating switching between two I2C/SMBus buses and four independent channels.
• Supports hot swapping capabilities without generating spikes on the selected bus lines.
• Includes active pull-up devices on all channel inputs and outputs to ensure defined logic levels.
• Features an internal reset circuit that initializes all switches to a known state upon power-up.

Specialized Applications

• Expanding I2C bus capacity by connecting multiple slave devices with identical addresses.
• Isolating sensitive components from bus noise or short circuits on other segments.
• Managing power consumption by disconnecting unused peripherals from the active bus.
• Facilitating system upgrades by adding new modules without disrupting existing hardware.

Specialized Procurement Notes

Verify the specific suffix 'G' against official NXP documentation to confirm lead-free compliance status, as packaging variations exist. Confirm the manufacturer origin, as this part number may also be produced under license by Texas Instruments. Ensure the procurement source provides valid RoHS certificates matching the current regulatory requirements for your region before finalizing orders.

Specialized Selection Notes

Select this component when designing systems requiring isolation between multiple I2C segments or address collision resolution. Verify that the required operating voltage falls within the 2.3 V to 5.5 V range. Consider the 24 Ohm on-resistance for signal integrity at high speeds. Ensure the PCB layout accommodates the 20-pin SOIC footprint and thermal dissipation needs for the specified power rating.

Specialized Part Context

This part belongs to the PCA9545 family of I2C multiplexers, which are widely used for bus expansion and protection. The 'D' suffix typically denotes the SOIC-20 package variant. While originally developed by Philips/NXP, Texas Instruments also manufactures equivalent parts under the same model number, ensuring pin-to-pin compatibility across manufacturers for design flexibility.

Specialized Replacement Considerations

The PCA9545APWR and PCA9545ARGYR are direct functional equivalents manufactured by Texas Instruments. These alternatives offer identical pinouts and specifications, allowing for seamless substitution in existing designs. Verify package compatibility (SOIC vs. TSSOP/QFN) when selecting a TI replacement to ensure mechanical fit.