MP1410

2A Step-Down

Switch-Mode Regulator

PRELIMINARY

MP1410 Rev 1.0_ 05/29/02

www.monolithicpower.com

3

Monolithic Power Systems

Figure 2: Functional Block Diagram

Σ

40/400KHz

Oscillator

Slope

Compensation

1.8V

Current

Comparator

Internal

Regulators

2

1uA

2.30/2.53V

0.7V

7

Shutdown

Comparator

Lockout

Comparator

3

4

M2

M1

6

1.22V

5

Error Amplifier

gm= 630uA/Volt

IN

EN

COMP

FB

GND

SW

BS

1

0.7V

Frequency

Foldback

Comparator

5V

CLK

S

R

Q

Q

Current

Sense

Amplifier

Pin Description

#

Name

Description

1

BS

High-Side Gate Drive Boost Input. BS supplies the drive for the high-side n-channel MOSFET switch.

Connect a 0.1µF or greater capacitor from SW to BS to power the high-side switch.

2

IN

Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive IN

with a 4.75V to 15V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise

on the input to the IC. See Input Capacitor.

3

SW

Power Switching Output. SW is the switching node that supplies power to the output. Connect the

output LC filter from SW to the output load. Note that a capacitor is required from SW to BS to power

the high-side switch.

4

GND

Ground.

5

FB

Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a resistive

voltage divider from the output voltage. The feedback threshold is 1.22V. See Setting the Output

Voltage

.

6

COMP

Compensation Node. COMP is used to compensate the regulation control loop. Connect a series RC

network from COMP to GND to compensate the regulation control loop. See Compensatiionr.

7

EN

Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the

regulator, drive it low to turn it off. For automatic startup, leave EN unconnected.

8

N/C

No Connect

BS 1

2

3

4

5

6

7

8

IN

SW

GND

N/C

EN

COMP

FB