HOW DOES IT WORK?

Step Down 8 Click is based on the MAX25232, a mini buck converter from Analog Devices. The MAX25232 features an under-voltage lockout, a soft-start timer, an on-chip oscillator, skip-mode operation, output-voltage overshoot protection, thermal-overload protection, and many more features. This current-mode-controlled buck converter operates at a 2.1MHz frequency, which guarantees no AM band interference, while it can also operate at 400KHz for minimum switching losses and maximum efficiency. While maintaining a 3A output current, it can stay in dropout by running at a 99% duty cycle. Voltage quality can be monitored by the host MCU.

To set the output voltage, this Click board™ uses the MCP4661, an 8-bit I2C digital potentiometer with non-volatile memory. It comes with 256 resistors and 257 wiper positions, while the last position is stored in an EEPROM. By setting the wiper value of resistance, you can set the output voltage of the MAX25232 converter available on the VOUT terminal. The Step Down 8 Click also features an unpopulated 3-pin header that allows you to set an operation mode. If you connect the SYNC pin to a GND or leave it unconnected, the device operates in a highly efficient pulse-skipping mode. If you connect SYNC to a BIAS pin or apply a clock to it, the device is in a forced-PWM mode (FPWM). Switching of modes can be done during the operation.

Step Down 8 Click uses a standard 2-Wire I2C interface of the MCP4661 to communicate with the host MCU, supporting 100KHz, 400KHz, and 3.4MHz frequencies. The I2C address can be set over the ADDR SEL jumpers, where the 0 position is selected by default. There is an EN enable pin to enable the converter and a PG power good pin that allows you to monitor the voltage quality. The Spread-Spectrum feature is an option that can be enabled over the SPS pin, offered to improve the EMI performance of the device. It does not interfere with the external clock applied to the SYNC pin.

This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

SPECIFICATIONS