MP2303 查看數據表（PDF） - Monolithic Power Systems

零件编号

产品描述 (功能)

生产厂家

MP2303

3A, 28V, 340KHz Synchronous Rectified Step-Down Converter

Monolithic Power Systems 

TM

MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER

INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE

To optimize the compensation components for

conditions not listed in Table 2, the following

procedure can be used.

1. Choose the compensation resistor (R3) to set

the desired crossover frequency. Determine the

R3 value by the following equation:

R3 = 2π × C2 × fC × VOUT

GEA × GCS VFB

Where fC is the desired crossover frequency,

34KHz.

Soft-Start Capacitor

To reduce input inrush current during startup, a

programmable soft-start is provided by

connecting a capacitor (C4) from pin SS to

GND. The soft-start time is given by:

t SS

= C4 ×

0.8V

6µA

To reduce the susceptibility to noise, do not

leave SS pin open. Use a capacitor with small

value if you do not need soft-start function.

2. Choose the compensation capacitor (C3) to

achieve the desired phase margin. For

applications with typical inductor values, setting

the compensation zero, fZ1, below one forth of

the crossover frequency provides sufficient

phase margin. Determine the C3 value by the

following equation:

External Bootstrap Diode

It is recommended that an external bootstrap

diode be added when the system has a 5V

fixed input or the power supply generates a 5V

output. This helps improve the efficiency of the

regulator. The bootstrap diode can be a low

cost one such as IN4148 or BAT54.

C3 >

4

5V

2π × R3 × fC

3. Determine if the second compensation

capacitor (C6) is required. It is required if the

ESR zero of the output capacitor is located at

less than half of the 340KHz switching

frequency, or the following relationship is valid:

1

< fS

2π × C2 × RESR 2

If this is the case, then add the optional

compensation capacitor (C6) to set the pole fP3

at the location of the ESR zero. Determine the

C6 value by the equation:

BS

MP2303

SW

10nF

MP2303_F02

Figure 2—External Bootstrap Diode

This diode is also recommended for high duty

cycle operation ( VOUT >65%) and high output

VIN

voltage (VOUT>12V) applications.

C6 = C2 × RESR

R3

MP2303 Rev. 0.92

www.MonolithicPower.com

11

5/2/2006

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

© 2006 MPS. All Rights Reserved.

Share Link: