UG-400 Datasheet, PDF (14/20 Pages) Analog Devices – Plug and play system evaluation

UG-400
POWER INPUT
An ac-to-dc desktop power supply is used to supply 7.5 V input
to the J1 barrel connector on the ezLINX hardware. This supply
connects to the UNREG_IN node of the circuit through a
protection circuit as shown in Figure 11.
Hardware User Guide
3.3 V POWER SUPPLY
The ADP1864 constant frequency, current-mode, step-down
dc-to-dc controller is used with an external P-channel MOSFET
to generate the regulated 3.3 V power supply for the ezLINX
hardware. The circuit implementation of the 3.3 V power
supply is shown in Figure 12.
J1
1
3
2
PWR CONN
UNREG_IN
F1
L1
D2
5A
190R
MBRS540T3G
1
2
4
3
D9
SMBJ24CA
C1 C2
1nF 1nF
PWR_SH_GND
FER1
600R
FER2
600R
PWR_SH_GND
GND
Figure 11. Power Input
GND
UNREG_IN
R2
24.9K
C4
470pF
C5
68pF
R3
80.6K
C3
10uF
P_GND
U1
1
COMP
3
FB
ADP1864
5
IN
4
CS
6
PGATE
R4
255K
A_GND
R1
0.05R
U2
1
5
2
6
3
7
4
8
SI4411DY
L2
2.5uH
3.3V
TP1
3.3V
TP2
GND
D3
MBRS540T3G
C6
C7
C245
220uF 4.7uF 0.01uF
P_GND
P_GND P_GND P_GND
GND
A_GND
W2
W1
COPPER
COPPER
4A
A_GND
P_GND
GND
Figure 12. 3.3 V Power Supply
Rev. 0 | Page 14 of 20