User guide

Evaluation Kit Hardware
Evaluation Kit (EK) User Guide 4-25
11115A–ATARM–27-Jul-11
4.3.3.2 Power Supplies
The EK Board features one adjustable LDO. It accepts DC 5V power input and outputs a regulated
+3.3V to most other circuits on the board through four 3.3V rails.
 VDDPIO0
 VDDPIO1
 VDDANA
 VDDISI
This LDO is enabled through a dual FET scheme. The processor can assert SHDN (which is a VDDBU-
powered I/O) to shut down the LDO to enter the so-called backup mode. The regulator on CM board is
also shut down by the action of the SHDN signal.
If the 3V battery is mounted on J5, both CM and EK boards can be woken up by action on the BP2 but-
ton, which drives the WKUP signal (also a VDDBU-powered I/O).
Figure 4-18. EK Board Power Management
JP4 SIP2
1 2
VBAT
R25 10k
VDDANA
D1
BAT54CLT1G
1
3
2
VDDISI
Place C22 near MN3.pin2
C57 100n
PWR_EN
R3 470R
D2 Red
12
Q6 IRLML2402
1
3 2
R2 47k
R8 10k
JP5 SIP2
12
R4 100k
R5 15k
POWER_EN
5V
PWR_EN#
FORCE POWER ON
SHDN
C8 1u
C7 1u
5V
C5 10n
3V3 3V3
C6 10u
VOUT = 0.8V x (Rtop + Rbottom)/Rbottom
MN3 RT9018A
PGOOD
1
EN
2
VIN
3
VDD
4
NC
5
VOUT
6
ADJ
7
GND
8
EP
9
C120 1u
R7 10k
Q1
Si1563EDH
1 32
456
R1 100k
C9 10u
C10
15p
3V3
3V3
L16 220ohm at 100MHz
1 2
L17 220ohm at 100MHz
1 2
L1 220ohm at 100MHz
1 2
L2 220ohm at 100MHz
1 2
VDDIOP0 VDDIOP1
J5
C4 100n
C22 1u