Logic Level Converter – Single Supply – Sparkfun PRT-14765
This Single Supply Logic Level Converter is a logic level and power supply translator on a small and neat breakout board.
This board breaks out the Texas Instruments TXB0104 4-bit bi-directional voltage-level translator with automatic direction sensing. With this logic level converter, you will be able to use your 5V logic microcontroller with 3.3V sensors without the second power supply!
What makes this Logic level converter truly special is the fact that you can supply it with 3.3V and it will create the 5V – meaning you can use your 3.3V system, and convert directly to another 5V sensor – and even power your sensor or other board!
This logic level converter provides 5V to the high side of the TXB0104 and the low side is programmable to 3.3V, 2.5V, and 1.8V. Please keep in mind that the default low side voltage is 3.3V.
Logic Level Converter Dimensions:
- Length: 27.9mm (1.1″)
- Width: 25.4mm (1″)
Logic Level Converter Schematic:
Single Supply Logic Level Converter Pin Out:
The Single Supply Logic Level Converter combines a boost converter (TPS61200), adjustable voltage regulator (MIC5205), and logic level translator (TXB0104) into one board. It provides 5V to the high side of the TXB0104 and the low side is programmable to 3.3V, 2.5V, and 1.8V. The default low side voltage is 3.3V. With this device, you can use your 5V microcontroller with 3.3V sensors and vice versa without the need for a second power supply! What makes this logic level converter truly special is the fact that you can supply it with 3.3V and it will boost it to 5V – meaning you can use your 3.3V system, and convert directly to another 5V sensor – and even power your sensor or other board! We will use a 3.3V microcontroller and a 5V sensor for the example. However, you can use still this board with a 5V microcontroller and a 3.3V sensor.
|VIN||Input Supply Voltage (3V – 5.5V)|
|VOUT, 5V||Boost Converter’s Voltage Output Set to 5V|
|VOUT, 3.3V||Regulated Voltage Output Set to 3.3V
(can be adjusted depending on resistor)
|A1-A4||Programmable VCCA Port for Lower TTL Logic Levels – Default = 3.3V|
|B1-B4||VCCB Port for Higher TTL Logic Levels – Set to 5V|
Each pin on this module is broken out for you to easily access ports A and B. Port A (A1-A4) is for low side TTL levels. This device’s VCCA is set to 3.3V by default but can easily be programmable with a resistor to 2.5V and 1.8V. Port B (B1-B4) is for high side TTL levels. VCCB is hard wired to 5V. VCCA should not exceed VCCB. Depending on which voltage is chosen for VCCA the data rate may vary.
Adjusting the Lower Voltage Side:
To adjust the reference voltage for the low side, you will need an associated resistor value to adjust the MIC5205’s output voltage. Below is a table of calculated resistor values that can be used.
|3.3V||Default = 13kΩ|