Freescale Semiconductor, Inc

FRDM-KL46Z

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Table 3. FRDM-KL46Z Power Supplies

Power Supply Name

Description

P5-9V_VIN

Power supplied from the VIN pin of the I/O headers (J9 pin 16). A

Schottky diode provides back drive protection.

P5V_SDA

Power supplied from the OpenSDA USB connector A Schottky

diode provides back drive protection.

P5V_KL46Z

Power supplied from the KL46Z USB connector 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 FRDM-KL46Z assembly. May be sourced from

P3V3_VREG, P3V3_BATT, or directly from the I/O headers (J9 pin

8)

P3V3_KL46Z

KL46Z MCU supply. Header J17 provides a convenient means for

energy consumption measurements. 2

P3V3_SDA

OpenSDA circuit supply. Header J9 provides a convenient means

for energy consumption measurements. 2

P5V_USB

Nominal 5V supplied to the I/O headers (J3 pin 10). Sourced from

either the P5V_K20D50M or P5V_OSDA supply through a back

drive protection Schottky diode.

NOTES:

1) By default the linear regulator, U1, 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 KL46 microcontroller has an operating range of 1.71V to 3.6V

2) J17 and J9 are not populated by default. The two pins of these headers are shorted together by a trace on

the bottom layer of the PCB. To measure the energy consumption of either the KL46 or the OpenSDA

MCU, the trace between these pins must first be cut. A current probe or a shunt resistor and voltage meter

can then be applied to measure the energy consumption on these rails.