MAX15157BEVKIT datasheet(3/16 Pages) MAXIM

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Evaluates: MAX15157B

MAX15157B Evaluation Kit

Soft-Start (SS)

The MAX15157B offers the SS pin to adjust soft-start

time to limit inrush current during startup. Soft-start times

are controlled by C13 for VOUT. An internal 5µA current

source charges the capacitor at the SS pin to provide a

linear ramping voltage for the output voltage reference.

The soft-start time of VOUT is calculated based on the

following equation:

tSS = C13 x VREFINX/5µA

where VREFINX is the reference voltage in Table 3

(2V for preset mode, 1.05V to 2V for tracking mode).

Note that during the initialization, the SS pin is held low

until UVLO exceeds its threshold voltage of 1V. The

drivers start switching once SS exceeds 50mV, and the

controller enables the fault-protection circuitry when SS

exceeds 1V.

Current-Limit Thresholds

and Current Monitor

The low- and high-side current sensing can be set by R1

and R2, respectively. R1 is used for cycle-by-cycle current

limit threshold. R2 is used for current monitor at a slower

control loop. Refer to the Output Fault Protection section

of MAX15157B data sheet for calculating the resistor R1

value and the Current Monitor section for the R2 resistor

value.

POW-OK (Power Good)

The MAX15157B EV kit provides the POW-OK output

(power-good output) test point. The POW-OK signal is

pulled up to the 4V6 BIAS by resistor R9, and POW-OK is

high when VOUT is above 90% of its programmed output

voltage. When VOUT is below 90% of its programmed

output voltage, POW-OK is pulled low.

#Denotes RoHS compliant.

Ordering Information

PART

TYPE

MAX15157BEVKIT#

EV Kit

MAX15157BEVKIT Datasheet(PDF) 3 Page - Maxim Integrated Products

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