MAXM17536 datasheet(17/22 Pages) MAXIM

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The MAXM17536 is designed to support a maximum load

current of 4A. The inductor ripple current is calculated as

follows:

OUT

0.071 I

0.051 I

L f

0.02 I







−

−×

∆=







−×







where:

VOUT = Steady-state output voltage

VIN = Operating input voltage

fSW = Switching frequency

L = Power module output inductance (4.7µH ±20%)

IOUT = Required output (load) current

The following condition should be satisfied at the desired

load current, IOUT:

OUT

7.15

∆

RESET Output

The MAXM17536 includes a comparator to monitor the

output voltage. The open-drain RESET output requires

an external pullup resistor. RESET goes high (high

impedance) 1024 switching cycles after the regulator

output increases above 95.5% of the designed

nominal regulated voltage. RESET goes low when the

regulator output voltage drops to below 92.5% of the

nominal regulated voltage. RESET also goes low during

thermal shutdown.

Prebiased Output

When the MAXM17536 starts into a prebiased output,

both the high-side and the low-side switches are turned

off so that the converter does not sink current from the

output. High-side and low-side switches do not start

switching until the PWM comparator commands the first

PWM pulse, at which point switching commences. The

output voltage is then smoothly ramped up to the target

value in alignment with the internal reference.

Thermal-Shutdown Protection

Thermal shutdown protection limits total power dissipation

in the MAXM17536. When the junction temperature of

the device exceeds +165°C (typ), an on-chip thermal sen-

sor shuts down the device, allowing the device to cool.

The thermal sensor turns the device on again after the

junction temperature cools by 10°C. Soft-start resets

during thermal shutdown. Carefully evaluate the total

power dissipation (see the Power Dissipation section)

to avoid unwanted triggering of the thermal shutdown in

normal operation.

Applications Information

Input-Capacitor Selection

The input-filter capacitor reduces peak currents drawn

from the power source and reduces noise and voltage

ripple on the input caused by the circuit’s switching.

The input capacitor RMS current requirement (IRMS) is

defined by the following equation:

IRMS = IOUT(MAX) × √

VOUT ×

(VIN −VOUT

)

VIN

where, IOUT(MAX) is the maximum load current. IRMS has

a maximum value when the input voltage equals twice

the output voltage (VIN = 2 x VOUT), so IRMS(MAX) =

IOUT(MAX)/2. Choose an input capacitor that exhibits less

than a +10°C temperature rise at the RMS input current

for optimal long-term reliability. Use low-ESR ceramic

capacitors with high ripple-current capability at the input.

X7R capacitors are recommended in industrial applications

for their temperature stability. The CIN capacitor values

in Table 1 are the minimum recommended values for the

associated operating conditions.

In applications where the source is located distant from

the MAXM17536 input, an electrolytic capacitor should

be added in parallel to the ceramic capacitor to provide

necessary damping for potential oscillations caused by

the inductance of the longer input power path and input

ceramic capacitor.

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Maxim Integrated │ 17

MAXM17536

4.5V to 60V, 4A High-Efficiency, DC-DC Step-Down

SiP Power Module with Integrated Inductor

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