Datasheet

FRDMKL25ZUM FRDM-KL05Z User's Manual Page 6 of 13
Figure 3. Power Supply Schematic
Table 3. FRDM-KL05Z Power Supplies
Power Supply Name
Description
P5-9V_VIN
Power supplied from the V
IN
pin of the I/O headers (J9 pin 8).
P5V_SDA
Power supplied from the OpenSDA USB connector (J2). A Schottky
diode provides back drive protection.
P3V3_VREG
Regulated 3.3V supply. Sources power to the P3V3 supply rail
through a back drive protection Schottky diode.
1
P3V3_BATT
Coin cell battery supply voltage. Sources power to the P3V3 supply
rail through a back drive protection Schottky diode.
P3V3
Main supply rail for the FRDM-KL05Z assembly. May be sourced from
P3V3_VREG, P3V3_BATT, or directly from the I/O headers (J9 pin 2)
P3V3_MCU
KL05Z MCU supply. Header J4 provides a convenient means for
energy consumption measurements.
2
P3V3_USBSER
OpenSDA circuit supply. Header J5 provides a convenient means for
energy consumption measurements.
2
P5V_USB
Nominal 5V supplied to the I/O headers (J9 pin 5). Sourced from
P5V_SDA supply through a back drive protection Schottky diode.
NOTES:
1) By default the linear regulator, U6, is a 3.3V output regulator. However, this is a
common footprint that would allow the user to modify the assembly to utilize an
alternative device such as a 1.8V or 2.5V regulator. The KL05Z microcontroller has an
operating range of 1.71V to 3.6V.
2) J4 and J5 are not populated by default. The two pins of these headers are shorted
together by a 0ohm resistor on the top layer of the PCB. To measure the energy
consumption of either the KL05Z or the OpenSDA MCU, the resistor between these pins
must first be removed. A current probe or a shunt resistor and volt meter can then be
applied to measure the energy consumption on these rails.