Source: https://www.pololu.com/product/3112
Timestamp: 2019-04-25 08:40:03+00:00

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The A-Star 32U4 Prime SV is a programmable board based on the ATmega32U4 AVR microcontroller and arranged in the common Arduino form factor. The A-Star Prime offers many additional features and improvements over competing products, including superior power management that enables efficient operation from 5 V to 36 V. This configuration of the A-Star 32U4 Prime SV includes microSD support and does not include any through-hole components; it is intended for those who want to customize the way it is assembled.
A-Star 32U4 Prime SV, bottom view.
The A* Prime supports the on-board microcontroller with many additional features and improvements over competing products, including enhanced connectivity and superior power management. The Prime is available in two main versions: SV, which features a green solder mask and a switching step-down regulator that allows operation from 5 V to 36 V, and LV, which features a blue solder mask and a step-up/step-down voltage regulator that allows operation from 2 V to 16 V. Each version is available in several different configurations: with or without preinstalled through-hole components like standard Arduino female headers and with or without microSD support. There is also a configuration available for each version with an 8×2 character LCD.
A-Star 32U4 Prime SV microSD (SMT Components Only).
This configuration of the A-Star 32U4 Prime SV includes microSD support and does not include any through-hole components. It ships as shown in the picture above, without any headers, a buzzer, or DC power jack. This configuration is intended for those who want to customize the way the board is assembled. We carry an A-Star Prime Accessory Pack that consists of a variety of through-hole components that can be installed on this board, including the parts necessary to make it just like our more assembled configurations (male and female 2×7 LCD headers are part of the accessory pack, but the LCD is sold separately). This is the SV version of the A-Star Prime, which operates from 5 V to 36 V.
As shown in the left graph below, the SV’s 5 V switching regulator has an efficiency – defined as (Power out)/(Power in) – of 80% to 95% for most combinations of input voltage and load.
The A-Star’s components, including the microcontroller and LEDs, draw 30 mA to 40 mA in typical applications (without the buzzer, microSD card, or an LCD). The rest of the regulator’s achievable output current, which depends on input voltage as well as ambient conditions, can be used to power other devices. The green line in the right graph above shows the output currents where the regulator’s output voltage drops below 4.75 V. These currents are close to the limits of the regulator’s capability and generally cannot be sustained for long periods; under typical operating conditions, a safe limit for the maximum continuous regulator output current is approximately 1 A.
The dropout voltage of a step-down regulator is defined as the minimum amount by which the input voltage must exceed the regulator’s target output voltage in order to assure the target output can be achieved. As can be seen in the graph below, the dropout voltage of the Prime SV’s regulator increases approximately linearly with the output current. For light loads where the dropout voltage is small, the board can operate down to 5 V. However, for larger loads, the dropout voltage should be taken into consideration when selecting a power supply; operating above 6 V will ensure the full output current is available.
Note: Batteries can have much higher voltages than their nominal voltages when fully charged, so be careful with nominal voltages above 24 V. A 36 V battery is not appropriate for this product.

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