R-IN32M4-CL3 User's Manual: Board design edition
7. 2.5-V built-in Regulator Peripheral Circuit Configuration
R18UZ0074EJ0100
Page 21 of 61
Dec 24, 2019
7.
2.5-V built-in Regulator Peripheral Circuit Configuration
This section describes the peripheral circuit configuration of the 2.5-V built-in regulator installed in R-IN32M4-CL3.
7.1
Peripheral Connection Configuration with 2.5-V built-in Regulator
This figure shows a peripheral connection configuration with the 2.5-V built-in regulator.
VDDREG_33
AVDDREG_33
AGND
REG_FB
REG_OUT
AGND
Schottky
barrier
diode
(SBD)
L = 4.7 µH
Ferrite bead
C = 10 µF
2.5-V built-in Regulator Part
C
BYPASS
= 0.01 µF
C
IN
= 47 µF
C
GND
GND
V
REG
= 2.5 V
V
DD
= 3.3 V
AGND
R-IN32M4-CL3 3.3 V Input
Other 3.3-V Input
VDD25A
(2.5 V for GbE-PHY)
C = 10 µF
GND
VDD11A
(1.15 V for GbE-PHY)
Ferrite bead
C
OUT
= 47 µF
With increasing VDD25A load current, the undershoot voltage increases and
2.5-V potential after smoothing rises.
To avoid it, the undershooting has to suppress by SBD.
Place these SBD, L, and C
OUT
close to the REG_OUT pin.
Place this
capacitor
close to the
AVDDREG_33
pin.
Place this
capacitor
as close to the
AVDDREG_33
pin as possible.
Select a power supply
smoothing capacitor
according to each board.
Bypass-capacitors for
the number of pins
C
BYPASS
= 0.1 µF
Place this
capacitor
close to the
VDDREG_33
pin.
Figure 7.1 Peripheral Connection Configuration with 2.5-V built-in Regulator
7.2
Peripheral Connection Configuration without 2.5-V built-in Regulator
This figure shows a peripheral connection configuration without the 2.5-V built-in regulator.
VDDREG_33
AVDDREG_33
AGND
REG_FB
REG_OUT
AGND
2.5-V built-in Regulator Part
C
GND
V
DD
= 3.3 V
AGND or GND
R-IN32M4-CL3 3.3 V Input
Other 3.3-V Input
Open circuit, or connect to
AGND or GND.
Select a power supply
smoothing capacitor
according to each board.
Figure 7.2 Peripheral Connection Configuration without 2.5-V built-in Regulator