MAX15034BEVKIT+ Maxim Integrated Products, MAX15034BEVKIT+ Datasheet - Page 19

• Manufacturer Part Number: MAX15034BEVKIT+
• Description: KIT EVALUATION FOR MAX15034
• Manufacturer: Maxim Integrated Products

Specifications of MAX15034BEVKIT+

• Main Purpose: DC/DC, Step Down
• Voltage - Input: 5 ~ 28V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: MAX15034
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Output: -
• Power - Output: -
• Frequency - Switching: -
• Outputs And Type: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

ripple current. A low-ESR input capacitor that can han-
dle the maximum input RMS ripple current of one chan-
nel must be used. The maximum RMS capacitor ripple
current is given by:
where I
is the output voltage of the same regulator and C
in Figure 6. The ESR of the input capacitors wastes
power from the input and heats up the capacitor.
Reducing the ESR is important to maintain a high overall
efficiency and in reducing the heating of the capacitors.
The worst-case peak-to-peak inductor ripple current,
the allowable peak-to-peak output ripple voltage, and
the maximum deviation of the output voltage during
Table 1. High-Side MOSFET Losses
Conduction Loss
Gate Drive Loss
Switching Loss
Output Loss
Configurable, Single-/Dual-Output, Synchronous
LOSS
Buck Controller for High-Current Applications
MAX
I
CIN RMS
is the full load current of the regulator. V
(
Losses associated with MOSFET on-time and
on-resistance. I
and duty cycle.
Losses associated with charging and
discharging the gate capacitance of the
MOSFET every cycle. Use the MOSFET’s (Q
specification.
Losses during the drain voltage and drain
current transitions for every switching cycle.
Losses occur only during the Q
time period and not during the initial Q
period. The initial Q
gate voltage from zero to V
side MOSFET driver’s on-resistance and R
is the internal gate resistance of the high-side
MOSFET (Q
MOSFET data sheet).
Losses associated with Q
occur every cycle when the high-side MOSFET
turns on. The losses are caused by both
MOSFETs, but are dissipated in the high-side
MOSFET.
)
______________________________________________________________________________________
≈
I
MAX
V
GD
OUT IN
RMS
and Q
Output Capacitors
DESCRIPTION
(
V
V
GS1
is a function of load current
IN
GS2
−
period is the rise in the
V
OSS
OUT
are found in the
TH.
of the MOSFET
R
)
GS2
DH_
IN
and Q
is the high-
is C5
GS1
OUT
GD
GATE
G
)
step loads determine the capacitance and the ESR
requirements for the output capacitors. The output rip-
ple can be approximated as the inductor current ripple
multiplied by the output capacitor’s ESR (R
The peak-to-peak inductor current ripple is given by:
During a load step, the allowable deviation of the output
voltage during the fast transient load dictates the output
capacitance and ESR. The output capacitors supply the
load step until the controller responds with a greater duty
cycle. The response time (t
closed-loop bandwidth of the regulator. The resistive
drop across the capacitor’s ESR and capacitor discharge
causes a voltage drop during a load step. Use a combi-
nation of SP polymer and ceramic capacitors for better
transient load and ripple/noise performance.
P
P
P
P
where I
where I
SWITCH
GATEDRIVE
CONDUCTION
OUTPUT
RMS
GATE
=
=
V
Q
ΔI
IN
≈
=
SEGMENT LOSS
OSS HS
=
L
V
×
=
2
=
DD
V
I
LOA
I
RMS
OUT
V
× (
(
V
IN
OUT
×
R
L f
RESPONSE
D D
)
(
DH
×
2
Q
2
+
×
×
×
V
G
(
Q
SW
1
I I
_
DD
LOAD
f
SW
R
OSS LS
−
−
+ + R
DS ON
Q
D
)
×
GD
(
GATE
(
(
) depends on the
Q
)
)
)
GS
×
×
)
I
f
GATE
SW
V
2
IN
+
ESR_OUT
×
Q
GD
f
SW
)
19
).