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LC-19A1E-BK/WH

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1

BS

I

Bootstrap.
This capacitor (C5) is needed to drive the power switch's gate above the supply voltage.
It is connected between the SW and BS pins to form a floating supply across the power switch driver.
The voltage across C5 is about 5V and is supplied by the internal +5V supply when the SW pin voltage is low.

2

IN

I

Supply Voltage.
The MP1415E-C100 operates from a +4.75V to +18V unregulated input.
C1 is needed to prevent large voltage spikes from appearing at the input.

3

SW

O

Switch.
This connects the inductor to either IN through M1 or to GND through M2.

4

GND

-

Ground.
This pin is the voltage reference for the regulated output voltage.
For this reason care must be taken in its layout.
This node should be placed outside of the D1 to C1 ground path to prevent switching current spikes from inducing 
voltage noise into the part.

5

FB

I

Feedback.
An external resistor divider from the output to GND, tapped to the FB pin, sets the output voltage.
To prevent current limit runaway during a short circuit fault condition the frequency foldback comparator lowers the 
oscillator frequency when the FB voltage is below 400mV.

6

COMP

-

Compensation.
This node is the output of the transconductance error amplifier and the input to the current comparator.
Frequency compensation is done at this node by connecting a series R-C to ground.
See the compensation section for exact details.

7

EN

I

Enable/UVLO.
A voltage greater than 2.62V enables operation.
Leave EN unconnected if unused.
An under voltage lockout (UVLO) function can be implemented by the addition of a resistor divider from VIN to GND.
For complete low current shutdown the EN pin voltage needs to be less than 700mV

8

SS

-

Soft-Start.
Connect SS to an external capacitor to program the soft-start.
If unused, leave it open.
open.

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1

SW2

O

Switching pin for buck boost.
Please connect inductor and diode.
Please minimize trace area to reduce EMI.

2

VIN

I

Input pin.
The capacitor is reguired to connect with input pin more than 10

µF.

3

SW1

I

Switching pin for boost.
Please connect inductor and diode.
Please minimize trace area to reduce EMI.

4

GND

-

Ground.

5

FB1

I

Feedback pin for boost.
Reference voltage is 2V.

6

VREF

I

Reference pin for buck boost.
The capacitor (1

µF/X5R) must be connected with vref pin.

7

FB2

I

Feedback pin for buck boost.
Reference voltage is 0.2V.

8

CNTRL

I

Control pin

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1

BST

I

Bootstrap.
This capacitor is needed to drive the power switch's gate above the supply voltage.
It is connected between SW and BS pins to from a floating supply across the power switch driver.

2

GND

-

Ground.
This pin is the voltage reference for the regulated output voltage.
For this reason care must be taken in its layout.
This node should be placed outside of the D1 to C1 ground path to prevent switching current spikes from 
inducing voltage noise into the part.

3

FB

I

Feedback.
An external resistor divider from the output to GND, tapped to the FB pin sets the output voltage.
To prevent current limit run away during a short circuit fault condition the frequency feedback comparator 
lowers the oscillator frequency when the FB voltage is below 250mV.

4

EN

I

On/Off Control input.
Pull above 1.2V to turn the device on.

5

IN

I

Supply voltage.
The MP2259 operates from a +4.5V to +16V unregulated input.
C1 is needed to prevent large voltage spikes from appearing at the input.

6

SW

O

Switch output.

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