NCP1582DR2GEVB ON Semiconductor, NCP1582DR2GEVB Datasheet - Page 10

• Manufacturer Part Number: NCP1582DR2GEVB
• Description: EVAL BOARD FOR NCP1582DR2G
• Manufacturer: ON Semiconductor

Specifications of NCP1582DR2GEVB

• Design Resources: NCP1582 EVB BOM NCP1582 EVB Schematic NCP1582DR2GEVB Gerber Files
• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 0.8V
• Voltage - Input: 4.5 ~ 12 V
• Regulator Topology: Buck
• Frequency - Switching: 350kHz
• Board Type: Fully Populated
• Utilized Ic / Part: NCP1582
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: NCP1582DR2G
• Other names: NCP1582DR2GEVBOS

Thermal Considerations
MOSFETs used, V
average MOSFET gate current typically dominates the
control IC power dissipation. The IC power dissipation is
determined by the formula:
Where:
The upper (switching) MOSFET gate driver losses are:
Where:
The lower (synchronous) MOSFET gate driver losses are:
The power dissipation of the NCP158x varies with the
P
I
V
P
P
Q
f
V
CC
SW
IC
TG
BG
CC
TG
BST
100
A
= control IC power dissipation,
= IC measured supply current,
= the switching frequency,
Figure 13. Gain Plot of the Error Amplifier
= top gate driver losses,
= bottom gate driver losses.
= IC supply voltage,
= total upper MOSFET gate charge at V
= the BST pin voltage.
P IC + (I CC @ V CC ) ) P TG ) P BG .
F
Z
Unloaded Gain
1000
Gain = GMR
Closed Loop,
P TG + Q TG @ f SW @ V BST .
P BG + Q BG @ f SW @ V CC .
CC
Compensation Network
, and the boost voltage (V
FREQUENCY (Hz)
Open Loop, Unloaded Gain
10 k
1
F
P
NCP1582
100 k
B
PHASE
Figure 14. Components to be Considered for
GND
TG
BG
Error Amplifier
1000 k
BST
BST
Layout Specifications
,
http://onsemi.com
). The
RETURN
V
in
10
Where:
calculated as:
Where:
IC package.
specifications section of this data sheet and a calculation can
be made to determine the IC junction temperature. However,
it should be noted that the physical layout of the board, the
proximity of other heat sources such as MOSFETs and
inductors, and the amount of metal connected to the IC,
impact the temperature of the device. Use these calculations
as a guide, but measurements should be taken in the actual
application.
Layout Considerations
very important. Switching current from one power device to
another can generate voltage transients across the
impedances of the interconnecting bond wires and circuit
traces. These interconnecting impedances should be
minimized by using wide, short printed circuit traces. The
critical components should be located as close together as
possible using ground plane construction or single point
grounding. The figure below shows the critical power
components of the converter. To minimize the voltage
overshoot the interconnecting wires indicated by heavy
lines should be part of ground or power plane in a printed
circuit board. The components shown in the figure below
should be located as close together as possible. Please note
that the capacitors C
physical capacitors. It is desirable to locate the NCP158x
within 1 inch of the MOSFETs, Q1 and Q2. The circuit
traces for the MOSFETs’ gate and source connections from
the NCP158x must be sized to handle up to 2 A peak current.
Q
The junction temperature of the control IC can then be
T
T
θ
The package thermal resistance can be obtained from the
As in any high frequency switching converter, layout is
JA
A
J
BG
C
= the junction temperature of the IC,
= the ambient temperature,
= the junction−to−ambient thermal resistance of the
in
= total lower MOSFET gate charge at V
L
out
T J + T A ) P IC @ q JA .
IN
and C
C
out
V
out
OUT
each represent numerous
C
A
D
L
CC
.