Renesas S3A1, User Manual

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Target Board Kit S3A1 (TB-S3A1) Hardware Layout
R12UM0022EU0100 Rev.1.00 Page 8 of 36
Feb 6, 2018
4.2.1 Power supply options
TB-S3A1 can be powered via several different methods:
Option 1: Debug USB (Default)
The default power source is 5V supplied from an external USB host to the USB Debug connector labelled DEBUG
USB on the top surface of the board. A low drop-out regulator (LDO) is used to convert the 5V signal to 3.3V, which
then is used to power the MCU and any connected devices.
Copper jumper E35 selects the source for the primary power input to the LDO regulator. By
default, this jumper is configured to provide power through the Debug USB connector. Copper
jumper E35 is closed for this configuration.
Option 2: Test Points TP3 and TP4
TB-S3A1 can also be powered by installing a 5V power source across TP3 (positive input) and TP4 (negative input).
Copper jumper E35 must be opened to enable powering the board using these test points.
The on-board Low Dropout Regulator (see Section 4.3: Major Components) has an input
voltage range of +3.3V to +5.5V, and a built-in current limit of 600 mA. Make sure any
external power source connected to TP3 & TP4 meets these requirements.
Figure 4 USB Debug Connector (J11), TP3, and TP4 on Target Board
Option 3: Test Points TP1 & TP2
TB-S3A1 can also be powered by installing a 3.3V source across TP1 (positive input) and TP2 (negative input).
Copper jumper E35 must be open to enable powering the board using these test points.
Figure 5 TP1, TP2 and LED1 on Target Board