Knowledge Base

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Buffer Pi - Legacy Product

Created 24/11/2016 | Bi-directional voltage-level translator for the Raspberry Pi

The Buffer Pi is a Bidirectional Voltage-Level Translator GPIO protection board which allows you to use 5V devices on your Raspberry Pi as well as protecting the Raspberry Pi GPIO pins from voltage spikes and static discharge.

The board is based around the TXS0108E and TXS0102 bidirectional voltage-level translator ICs from Texas Instruments.  Polyfuse protection is provided on the 3.3V and 5V rails to reduce the risk of damage to your Raspberry Pi from current surges and electrolytic capacitors provide voltage smoothing for connected devices.

The Buffer Pi is pin compatible with the the Raspberry Pi model B+.

 

The Buffer Pi is compatible with I2C and UART based devices and allows you to set the buffered GPIO voltage to 3.3V or 5V via a voltage selection jumper pin.

Schematic

Click to download
Click to download schematic PDF.

 

Datasheets

Texas Instruments TXS0108E

Texas Instruments TXS0102

Specifications

The Buffer Pi can supply up to 50mA combined across the IO pins. 

Overcurrent protection is provided with a 50mA polyfuse on the 3.3V rail and a 500mA polyfuse on the 5V rail.

The voltage level on the buffered GPIO port can be selected using the voltage select jumper. 

Setting the jumper to 3.3V will set a maximum voltage of 3.3V across the GPIO pins, this is recommended for use with Raspberry Pi expansion boards. 

Setting the jumper to 5V will set a maximum voltage of 5V across the GPIO pins allowing you to connect 5V logic devices to your Raspberry Pi.

Please Note: Some SPI devices may not function correctly when using the Buffer Pi board. This appears to be due to the longer data lines connecting to the Raspberry Pi's SPI pins and the device being used. 

 

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