8

Rev.1.2

9. PCB layout guide

To stabilize the operation, PCB layout is very important. Please take the following guidelines as reference.

1) Keep the path of switching current as short as possible; minimize the loop area which is connected to input

capacitor, high-side and low-side MOSFETs.

2) Bypass ceramic capacitors are recommended to be connected as close to VIN as possible.

3) Please connect all feedback loop wire in the shortest way. Locate feedback resistors and compensation

components as close to the chip as possible.

4) Locate wire of SW away from sensitive analog areas such as FB.

5) To cool down the operation temperature of the chip and gain higher long-term reliability, please connect

VIN, SW, and especially GND respectively to a large copper area.

11 -

For external BS diode, ELM recommends IN4148; BS capacitors between 0.1 to 1μF are preferable.

To improve efficiency when Vin is ≤ 6V, it is possible to add an external Schottky diode between IN and BS.

SW

BS

GND

VIN

ELM611DA

Schottky

(B0520LW)

5V to 6V

Vout

▲

* Add a Schottky diode to improve efficiency when Vin is ≤ 6V.

SOP-8

■Marking

ELM

611DA

abc

high efficiency synchronous PWM step down DC/DC converter

Mark

Content

ELM611DA

Product name

abc

Assembly lot No.:

000 to 999 repeated