EV2905-K-01A HYSTERETIC SYNCHRONOUS STEP-DOWN CONTROLLER EV BOARD

NOTICE:

The information in this document is subject to change without notice. Users should warrant and guarantee that third

party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not

assume any legal responsibility for any said applications.

EV2905-K-01A Rev. 1.0

www.MonolithicPower.com

5

12/7/2017

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

Preliminary Specifications Subject to Change

© 2017 MPS. All Rights Reserved.

QUICK START GUIDE

1. Stuff multi-strand wire in VOUT, VOUT_GND pad and single strand wire in VIN, VIN_GND pad.

2. Connect the positive terminal of the load to VOUT multi-strand wire, and the negative terminal of

the load to GND multi-strand wire.

3. Preset the power supply output to 12V and turn it off.

4. Connect the positive terminal of the power supply output to the VIN wire and the negative

terminal of the power supply output to the GND wire.

5. Connect the EN pin to GND.

6. Turn the power supply on. The MP2905EK will automatically startup.

7. To use the Enable function, drive EN higher than 4V to turn on the MOS Q3, then SS is pulled

down, part shuts down. Drive EN less than 0.5V to turn off the MOS Q3, then SS is released,

part turns on. Do not float EN pin.

8. The output voltage VOUT can be programmed by R1 and R2. Calculate the new value using the

formula:

)

1

(

2

1







FB

OUT

V

V

R

R

In order to get good transient, R1 and R2 should be small enough. Always set R2=1kΩ or

smaller, and R1 is not higher than 3 kΩ.

9. The frequency is set by C9 and R13. C9 should not be small enough to get good transient

response, 2.2nF is recommended , then R13 is used to program the frequency by formula below:

HY

IN

OUT

IN

IN

OUT

IN

out

V

C

V

V

ns

V

ns

V

f

V

V

V

R





















9

13

)

20

90

(

)

(

10. The EV board is designed for 12V input, 1.2Vout application. So, for other application, some

parameters such as current limit and frequency need to be redesigned. Please refer to AN023

to set related parameters.