25VT6A5VGEVB
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3
ELECTRICAL SPECIFICATIONS
Table 1. ELECTRICAL SPECIFICATIONS FOR 25VT6A5VGEVB
Parameter
Notes and Conditions
Min
Typ
Max
Units
Input Characteristics
V
in
Input Voltage
−
8
12
16
V
V
drvr
Driver Voltage
−
4.5
5
6.5
V
V
CC
Controller Voltage
−
0
5
7
V
I
in
Input Current
V
in
= 12 V; I
out
= 25 A
0
−
3
A
No load input current
V
in
= 12 V; I
out
= 0 A; V
drvr
= 5 V
0
9
−
mA
Output Characteristics
V
out
*Output Voltage
V
in
= 12 V; I
out
= 25 A
0.8
1.2
1.8
V
V
p
−
p
Maximum Switch Node
Voltage
V
in
= 12 V; I
out
= 20 A; V
drvr
= 5 V
−
16
−
V
I
out
Output Current
V
in
= 8 V to 16 V
0
−
25
A
System Characteristics
F
SW
Switching Frequency
Note 1
−
50
0
−
kHz
h
Peak
Peak Efficiency
V
in
= 12 V; V
out
= 1.2 V; V
drvr
= 5 V
−
91
−
%
h
Full load efficiency
V
in
= 12 V; V
out
= 1.2 V; V
drvr
= 5 V; I
out
= 25 A
−
87
−
%
*The output voltage can be adjusted by changing the VID settings. See Appendix.
1. The switching frequency is defined by the resistors R13 and R14 and can only be changed only by changing the resistors R13 and R14.
CONNECTORS AND TEST POINTS DESCRIPTIONS
Input Power
Connect the input voltage positive probe to Pin 1 of J1 and
sense probe at J9, negative probe to the GND at Pin 2 of J1
and sense probe at J10. The input voltage can range from 8 V
to 16 V.
Output Power
Connect the output voltage positive probe to J13 (large
screw connector) and sense probe at J11, ground probe at J14
(large screw connector) and the sense probe to J12. The
output voltage is set by the VID settings (SW2) and the
potentiometer (R60). Please refer to Start-Up Procedure and
Appendix.
Controller Biasing
Connect the positive probe to Pin 2 of J5 and the negative
probe to the GND at Pin 1 of J5. Please keep this as a separate
supply to avoid damage to the controller, especially when
other drive voltages are used.
Driver Biasing
The driver positive voltage probe V
CC
should be
connected to both pin 1 and 2 of J6. The driver voltage is
defined in Table 1. The 25VT6A5VGEVB evaluation board
is set up to accept DFN8 footprints of ON Semiconductor
5 V drivers.
Switching Frequency
The converter switching frequency is set by the voltage
divider setup of R13 and R14 between the pins 10 (ROSC)
and 33 (AGND) of the NCP5386 controller. In order to
change the frequency, these resistors have to be changed.
Changing the frequency also changes the I
lim
(Over Current
shutdown threshold) settings.
Table 2. R13, R14 1% RESISTOR VALUES FOR
FREQUENCY SET
Frequency (kHz)
R13 (k
W
)
R14 (k
W
)
300
26.7
7.32
400
19.1
5.23
500
14.7
4.02
600
12.1
3.24
700
10.0
2.74