17
82575 Ethernet Controller Design Guide

The 1.8 V rail has a lower current requirement; however, the use of a SVR is still

recommended for adequate margin. Using an LVR in this application is acceptable as

long as adequate margin exists in the design, and sequencing can be controlled. Figure

3 shows an example of a compact low-part -count LVR that could be used for the 1.8 V

supply.

Figure 4. Example of Linear Voltage R egulator for 1.8 V power rail

3.4.1 82575 Ethernet Controller Power Sequencing

Regardless of which type of regulator used, all regulators need to adhere to the

sequencing shown in Figure 5 to avoid latch-up and forward-biased internal diodes.

RAENIL_0V1CCV
DNG
8V1CCV_
3V3CCV
RAENIL_8V1CCV
3V3CCV
DNG
DNG
eb dluohS
mhoK5<
R5X
R5X
R5X

rotalugeR raeniL v0.1 >- v8.1

>>noitceleS rotsiseR rotalugeR<<

))nwodR/puR(+1(*bfV=tuoV

nwodR*)1-)bfV/tuoV((=puR

mhoK1=K1*)1-)5.0/0.1((=puR

)A2( v0.1=tuoV

rotalugeR raeniL v8.1 >- v3.3

>>noitceleS rotsiseR rotalugeR<<

)nwodR*jdaI(+))puR/nwodR(+1(*bfV=tuoV

:mho002=nwodR nehW

mho074~=464=)1-)52.1/))002*u55(-8.1(((/)002(=puR

v8.1=tuoV
1206
6021

tupni v3.3 roF

bfV egnahC

srotsiseR

mhoK2.1 ot egnahC
roF
92C
u22
Y
92C
u22
Y
54R
K1
Y
54R
K1
Y
96R
002
Y
96R
002
Y
64R
K1
Y
64R
K1
Y
76R
0
N
76R
0
N
93C
u01
Y
93C
u01
Y
03C
u01
Y
03C
u01
Y
74R
K001
Y
74R
K001
Y
08R
0
N
08R
0
N
83C
u01
Y
83C
u01
Y
74C
u2.2
Y
74C
u2.2
Y
86R
0
Y
86R
0
Y
Vout 2
Adj 1
Vin 3
Vout
4
1U
Y
1U
Y
07R
074
Y
07R
074
Y
77R
0
Y
77R
0
Y
1NI
2
2NI
3
3NI
4
4NI
5
NE
1
1TUO 01
2TUO 11
3TUO 21
4TUO 31
BF 9
KOP
6
GND
8
2PT 41
1PT 7
E_PAD
15
3U3U
8257582575
82575