Datasheet

FRDMKL25ZUM FRDM-KL05Z User's Manual Page 5 of 13
Figure 2. FRDM-KL05Z Feature Call-outs
5 FRDM-KL05Z Hardware Description
5.1 Power Supply
There are multiple power supply options on the FRDM-KL05Z. It can be powered from the USB
connector, the V
IN
pin on the I/O header, an on-board coin cell battery, or an off-board 1.71-3.6V
supply from the 3.3V pin on the I/O header. The USB and V
IN
supplies are regulated on-board using a
3.3V linear regulator to produce the main power supply. The other two sources are not regulated on-
board. Table 2 provides the operational details and requirements for the power supplies.
Table 2. Power Supply Requirements
Supply Source
Valid Range
OpenSDA
Operational?
Regulated on-
board?
OpenSDA USB (J2)
5V
Yes
Yes
V
IN
Pin
4.3-9V
No
Yes
3.3V Pin
1.71-3.6V
No
No
Coin Cell Battery
1.71-3.6V
No
No
Note that the OpenSDA circuit is only operational when a USB cable is connected and supplying power
to J2. However, protection circuitry is in place to allow multiple sources to be powered at once.
Figure 3 shows the schematic drawing for the power supply inputs and the on-board voltage regulator.