MAX15049 Evaluation Kit

4 ______________________________________________________________________________________

Triple Outputs

The MAX15049 EV kit’s three outputs are configured to

different voltages. The bottom side of the PCB contains

the IC and the feedback and compensation compo-

nents. The top side of the PCB contains the input/output

capacitors, inductors, and FETs. OUT1 is configured to

3.3V with resistors R3 and R6 and can supply up to 3A.

OUT2 is configured to 1.8V with resistors R9 and R12

and can supply up to 3A. OUT3 is configured to 1.2V

with resistors R16 and R18 and can supply up to 6A.

The output voltage for each output can be reconfigured

between 0.6V and 3.3V by replacing the respective feed-

back resistors. Refer to the Type III: Compensation When

IC data sheet for instructions on selecting new resis-

tor values for the respective outputs. Also, refer to the

Inductor Selection and Input-Capacitor Selection sec-

tions in the IC data sheet to verify other component

replacements for proper operation when changing the

output voltage.

Current Limit

The MAX15049 EV kit uses the low-side MOSFET DC

current-limit threshold is 69mV internally set inside

the MAX15049. The MAX15049 compares the voltage

threshold to incorporate the current limit. OUT1 and

9.5mI (typ) and 13.5mI (max). The current-limit thresh-

old is 69mV (typ) and the output current limit calculated

is approximately 6A. The IRF7907 FET has similar char-

and therefore, a similar current limit.

Switching Frequency

The MAX15049 PWM switching frequency is set to appro-

ximately 500kHz with resistor R21 (39.2kI). Replace

resistor R21 with a new resistor value to progam the

switching frequency between 200kHz and 1.2MHz. Use

the following equation to choose the appropriate resistor

(

)

( )

SW

f

kHz

12.8 R21 k

=

×

Ω

Evaluating the MAX15048 (Tracking)

The MAX15049 EV kit comes configured for sequencing.

The EV kit can also evaluate the MAX15048 for tracking

applications. The MAX15049 IC must be replaced with

the MAX15048. It also requires modification at EN2

(pin 9) and EN3 (pin 24) for tracking operation with

the MAX15048. Refer to the MAX15048 Coincident/

Ratiometric Tracking (EN_) section in the MAX15048/

MAX15049 IC data sheet to calculate the proper values

for resistors R23–R26 and R29.

PGOOD Status Output

The MAX15049 EV kit provides a PGOOD logic output to

indicate the regulation state of OUT1, OUT2, and OUT3.

A logic-low at TP8 (PGOOD test point) indicates that one

of the output voltages has dropped below 92% of its

regulation voltage.

Individual EN_ Input

The MAX15049 EV kit provides an individual enable test

point for each output. The EV kit comes configured for

sequencing and connections so the enable test points

are not needed. To disable sequencing and externally

control each output, remove the sequencing compo-

nents (R23–R28) and apply a voltage on the EN_ test

point.