MAX15053_V01 datasheet(11/21 Pages) MAXIM

11 / 21 page

Detailed Description

The MAX15053 high-efficiency, current-mode switch-

ing regulator can deliver up to 2A of output current. The

MAX15053 provides output voltages from 0.6V to 0.94 x

VIN from 2.7V to 5.5V input supplies, making the device

ideal for on-board point-of-load applications.

The MAX15053 delivers current-mode control architec-

ture using a high gain transconductance error amplifier.

The current-mode control architecture facilitates easy

compensation design and ensures cycle-by-cycle current

limit with fast response to line and load transients.

The MAX15053 features a 1MHz fixed switching frequen-

cy, allowing for all-ceramic capacitor designs and fast

transient responses. The high operating frequency mini-

mizes the size of external components. The MAX15053 is

available in a 1.5mm x 1.5mm (3 x 3 array) x 0.5mm pitch

WLP package.

The MAX15053 offers a selectable skip-mode functional-

ity to reduce current consumption and achieve a higher

efficiency at light output loads. The low RDS(ON) inte-

grated switches (30mI high-side and 18mI low-side,

typ) ensure high efficiency at heavy loads while minimiz-

ing critical inductances, making the layout design a much

simpler task with respect to discrete solutions. Utilizing a

simple layout and footprint assures first-pass success in

new designs.

The MAX15053 features 1MHz Q15%, factory-trimmed,

fixed-frequency PWM mode operation. The MAX15053 also

offers capacitor-programmable, soft-start reducing inrush

current, startup into PREBIAS operation, and a PGOOD

open-drain output for sequencing with other devices.

Controller Function–PWM Logic

The controller logic block is the central processor that

determines the duty cycle of the high-side MOSFET

under different line, load, and temperature conditions.

Under normal operation, where the current-limit and

temperature protection are not triggered, the controller

logic block takes the output from the PWM comparator

and generates the driver signals for both high-side and

low-side MOSFETs.The control logic block controls the

break-before-make logic and all the necessary timing.

Thehigh-sideMOSFETturnsonatthebeginningofthe

oscillator cycle and turns off when the COMP voltage

crosses the internal current-mode ramp waveform, which

is the sum of the slope compensation ramp and the

current-mode ramp derived from inductor current (current-

senseblock).Thehigh-sideMOSFETalsoturnsoffifthe

maximum duty cycle is 94%, or when the current limit is

reached.Thelow-sideMOSFETturnsonfortheremain-

der of the oscillation cycle.

Starting into a Prebiased Output

The MAX15053 can soft-start into a prebiased output

without discharging the output capacitor. In safe pre-

biased startup, both low-side and high-side MOSFETs

remain off to avoid discharging the prebiased output.

PWM operation starts when the voltage on SS/REFIN

crossesthevoltageonFB.

The MAX15053 can start into a prebiased voltage higher

than the nominal set point without abruptly discharg-

ing the output. Forced PWM operation starts when the

SS/REFINvoltagereaches0.58V(typ),forcingthecon-

verter to start. In case of prebiased output, below or above

the output nominal set point, if low-side sink current-limit

threshold (set to the reduced value of -0.4A (typ) for the

first 32 clock cycles and then set to -4A typ) is reached,

the low-side switch turns off before the end of the clock

period, and the high-side switch turns on until one of the

following conditions is satisfied:

•

High-side source current hits the reduced high-side

current limit (0.4A, typ); in this case, the high-side

switch is turned off for the remaining time of the clock

period.

•

The clock period ends. Reduced high-side current

limit is activated to recirculate the current into the

high-side power switch rather than into the internal

high-side body diode, which could be damaged.

Low-side sink current limit is provided to protect the

low-side switch from excessive reverse current during

prebiased operation.

In skip mode operation, the prebias output needs to be

lower than the set point.

Enable Input

The MAX15053 features independent device enable con-

trol and power-good signal that allow for flexible power

sequencing. Drive the enable input (EN) high to enable

the regulator, or connect EN to IN for always-on opera-

tion. Power-good (PGOOD) is an open-drain output that

asserts when VFB is above 555mV (typ), and deasserts

low if VFB is below 527mV (typ).

Programmable Soft-Start (SS/REFIN)

The MAX15053 utilizes a soft-start feature to slowly

ramp up the regulated output voltage to reduce input

inrush current during startup. Connect a capacitor from

SS/REFINtoGNDtosetthestartuptime(seetheSetting

the Soft-Start Time

section for capacitor selection details).

MAX15053

High-Efficiency, 2A, Current-Mode Synchronous,

Step-Down Switching Regulator

www.maximintegrated.com

Maxim Integrated │ 11

MAX15053 Datasheet(PDF) 11 Page - Maxim Integrated Products

MAX15053 Datasheet(HTML) 11 Page - Maxim Integrated Products

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Datasheet Download

Link URL