MP2176 – 6V, 6A, SYNCHRONOUS, STEP-DOWN CONVERTER

MP2176 Rev. 1.0

www.MonolithicPower.com

11

4/17/2018

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

© 2018 MPS. All Rights Reserved.

PIN FUNCTIONS

PIN #

Name

Description

1

AGND

Analog ground.

2

FB

Feedback. The output voltage is set by an external resistor divider from the output to

GND tapped to FB. The resistor divider should be placed as close to FB as possible.

Avoid placing vias on the FB traces.

3

SS

Soft start. Connect an external capacitor to SS to program the soft-start time for the

switch-mode regulator.

4

EN

Enable. Pull EN higher than 1.8V to enable the chip. For automatic start-up, connect EN

to VIN with a 100k

Ω resistor. EN can be used to set the on/off threshold (adjust UVLO)

with two additional resistors.

5

VCC

External bias supply voltage for the driver and control circuits. For 1.5V to 3V input

applications, provide VCC with a separate 3.3V/5V bias supply. For 3V to 6V input

applications, provide VCC with a separate 3.3V/5V bias supply or tie VCC to VIN with a

10

Ω resistor. Decouple VCC with a minimum 4.7µF ceramic capacitor placed as close to

VCC as possible. X7R or X5R grade dielectric ceramic capacitors are recommended for

their stable temperature characteristics.

6

PG

Power good output. PG is high if the output voltage is higher than 90% of the nominal

voltage. There is a delay from the time FB becomes greater than or equal to 90% to

when PG goes high.

7

BST

Bootstrap. A capacitor connected between SW and BST is required to form a floating

supply across the high-side switch driver.

8 - 9

GND

System ground. GND is the reference ground of the regulated output voltage. For this

reason, care must be taken during the PCB layout.

10 - 11

IN

Supply voltage. IN supplies power for the internal MOSFET and regulator. The MP2176

operates from a +3V to +6V input rail. An input capacitor is needed to decouple the input

rail. Use wide PCB traces and multiple vias to make the connection.

12

FREQ

Frequency setting. A resistor connected between FREQ and IN is required to set the

switching frequency. The on time is determined by the input voltage and the resistor

connected to FREQ. IN connected through a resistor is used for line feed-forward and

makes the frequency constant during the input voltage

’s variation. It is recommend to

use a 10pF decoupling capacitor from FREQ to GND.

13 - 14

SW

Switch output. Connect SW to the inductor and bootstrap capacitor. SW is driven up to

VIN by the high-side switch during the on time of the PWM duty cycle. The inductor

current drives SW negative during the off time. The on resistance of the low-side switch

and the internal Schottky diode fixes the negative voltage. Use wide PCB traces to make

the connection.