MAX15037ATE+ Maxim Integrated Products, MAX15037ATE+ Datasheet - Page 15

• Manufacturer Part Number: MAX15037ATE+
• Description: IC DC/DC CONV 3A 16-TQFN-EP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX15037ATE+

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.6 ~ 23 V
• Current - Output: 3A
• Frequency - Switching: 200kHz ~ 2.2MHz
• Voltage - Input: 4.5 ~ 23 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-TQFN Exposed Pad
• Power - Output: 2.67W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The input ripple comprises mainly of ΔV
capacitor discharge) and ΔV
the input capacitor). The total voltage ripple is the sum of
ΔV
the ESR and the capacitor discharge is equal to 50%
each. The following equations show the ESR and capaci-
tor requirement for a target voltage ripple at the input:
where
where I
and f
input capacitance at lower input voltages to avoid pos-
sible undershoot below the UVLO threshold during
transient loading.
The allowable output voltage ripple and the maximum
deviation of the output voltage during step load cur-
rents determine the output capacitance and its ESR.
The output ripple comprises of ΔV
capacitor discharge) and ΔV
the output capacitor). Use low-ESR ceramic or alu-
minum electrolytic capacitors at the output. For alu-
minum electrolytic capacitors, the entire output ripple is
contributed by ΔV
culate the ESR requirement and choose the capacitor
accordingly. If using ceramic capacitors, assume the
contribution to the output ripple voltage from the ESR
and the capacitor discharge to be equal. The following
equations show the output capacitance and ESR
requirement for a specified output voltage ripple.
Q
and ΔV
SW
OUT
is the switching frequency. Use additional
ΔI
ESR
is the output current, D is the duty cycle,
P P
−
. Assume the input voltage ripple from
C
ESR
C
ESR
______________________________________________________________________________________
IN
=
OUT
(
ESR
=
V
=
. Use the ESR
IN
I
=
OUT
⎛
⎜
⎝
D
V
I
2.2MHz, 3A Buck or Boost Converters
Δ
−
OUT
8
IN
=
=
V
V
×
Output Capacitor Selection
Q
OUT
Δ
Δ
×
V
×
with an Integrated High-Side Switch
Δ
Δ
ESR
OUT
V
ESR
V
V
Δ
f
D
×
+
I
V
SW
IN
ESR
ESR
P-P
I
Q
f
(
P-P
Δ
SW
1
)
I
−
×
×
(caused by the ESR of
(caused by the ESR of
P P
×
2
f
D
V
−
SW
L
OUT
OUT
)
Q
⎞
⎟
⎠
Q
(caused by the
equation to cal-
and
(caused by the
where:
ΔI
above and f
frequency.
The allowable deviation of the output voltage during
fast transient loads also determines the output capaci-
tance and its ESR. The output capacitor supplies the
step load current until the controller responds with a
greater duty cycle. The response time (t
depends on the closed-loop bandwidth of the convert-
er. The high switching frequency of the MAX15036/
MAX15037 allows for a higher closed-loop bandwidth,
thus reducing t
requirement. The resistive drop across the output
capacitor’s ESR and the capacitor discharge causes a
voltage droop during a step load. Use a combination of
low-ESR tantalum and ceramic capacitors for better
transient load and ripple/noise performance. Keep the
maximum output voltage deviation below the tolerable
limits of the electronics being powered. When using a
ceramic capacitor, assume an 80% and 20% contribu-
tion from the output capacitance discharge and the
ESR drop, respectively. Use the following equations to
calculate the required ESR and capacitance value:
where I
response time of the controller. The controller response
time depends on the control-loop bandwidth.
The MAX15036 can be configured for step-up conver-
sion since the internal MOSFET can be used as a low-
side switch. Use the following equations to calculate
the inductor (L
capacitor (C
operation.
P-P
is the peak-to-peak inductor current as calculated
STEP
SW
OUT
V
Δ
is the load step and t
C
OUT RIPPLE
I
MIN
P P
RESPONSE
OUT
is the individual converter’s switching
−
) when using the converter in boost
), input capacitor (C
_
ESR
=
=
(
V
I
STEP
OUT
IN
V
−
IN
and the output capacitance
≅
V
=
×
OUT
×
Δ
Δ
t
Δ
I
V
RESPONSE
f
STEP
V
SW
V
ESR
Q
ESR
)
×
Boost Converter
×
V
+
L
OUT
Δ
RESPONSE
V
IN
Q
), and output
RESPONSE
is the
15
)