LM2653-ADJEVAL National Semiconductor, LM2653-ADJEVAL Datasheet

LM2653-ADJEVAL

Manufacturer Part Number

LM2653-ADJEVAL

Description

EVALUATION BOARD FOR LM2653-ADJ

Manufacturer

National Semiconductor

Datasheets

1.LM2653MTCX-ADJNOPB.pdf (12 pages)

2.LM2653-ADJEVAL.pdf (3 pages)

Specifications of LM2653-ADJEVAL

Main Purpose

DC/DC, Step Down

Outputs And Type

1, Non-Isolated

Voltage - Output

2.5V

Current - Output

1.5A

Voltage - Input

4 ~ 14V

Regulator Topology

Buck

Frequency - Switching

300kHz

Board Type

Fully Populated

Utilized Ic / Part

LM2653

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Power - Output

Other names

*LM2653-ADJEVAL

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LM2653EVAL 1.5A

Synchronous Switching

Regulator Evaluation Board

Introduction

The LM2653 switching regulator provides high efficiency

power conversion over a 100:1 load range (1.5A to 15mA).

This

battery-powered applications.

Synchronous rectification and 75 mΩ internal switches pro-

vide up to 97% efficiency. At light loads, the LM2653 enters

a low power hysteretic or “sleep” mode to keep the efficiency

high. In many applications, the efficiency still exceeds 80%

at 15 mA load. A shutdown pin is available to disable the

LM2653 and reduce the supply current to 7 µA.

The IC contains patented current sensing circuitry for current

mode control. This feature eliminates the external current

sensing required by other current-mode DC-DC converters.

The IC has a 300kHz fixed frequency internal oscillator. The

high oscillator frequency allows the use of extremely small,

low profile components.

The evaluation board can be obtained by ordering part num-

ber LM2653EVAL from your local National Semiconductor

sales office, or National’s website at http://www.national

.com.

Evaluation Board Design

The evaluation board is designed to supply 2.5V at up to

1.5A. The input voltage range is 4V to 14V. Components

CIN (input capacitor)

CIN2 (input capacitor)

CB (bootstrap capacitor)

CSS (softstart capacitor)

COUT (output capacitor)

CC1 (compensation)

feature

makes

Designation

the

LM2653

AN101132

TABLE 1. Parts List (Bill Of Materials)

FIGURE 1. LM2653 EVAL Schematic

ideal

22µH, Coilcraft DO3316P-223

100µF, 16V, Sprague 594D107X0016D2T

0.1µF ceramic capacitor

4.7nF ceramic capacitor

120µF, 6.3V, Sprague 594D127X06R3C2T

2.2nF ceramic capacitor

fit

National Semiconductor

Application Note 1133

Dongyan Zhou

May 1999

were selected based on the design procedure in the LM2653

datasheet. The feedback resistors can be adjusted to

achieve a different output voltage:

Choose 1% resistors between 10kΩ to 100kΩ for R1 and

R2.

PCB layout is critical to reduce noises and ensure specified

performance. See the LM2653 datasheet for layout guide-

lines. The artwork for the evaluation board is shown at the

end of this application note.

The schematic for the evaluation board is shown in Figure 1,

and the parts list is given in Table 1.

When the undervoltage protection occurs, the output voltage

can be pulled below ground as the inductor current is re-

versed through the synchronous FET. For applications which

need to be protected from a negative voltage, a clamping

diode D2 is recommended.

The PGOOD flag goes low whenever the overvoltage or

undervoltage latch protection is enabled. The overvoltage

protection will be enabled immediately when the output volt-

age exceeds 110% of its nominal. While the undervoltage

latch protection will wait for a period of time set by the

LDELAY capacitor. If the output voltage is still below 80% of

its nominal after this waiting period, the latch protection will

be enabled.

Description

OUT

= 1.238V x [1+ (R

10113201

)]

www.national.com

Related parts for LM2653-ADJEVAL

LM2653-ADJEVAL Summary of contents

Page 1

... LM2653 battery-powered applications. Synchronous rectification and 75 mΩ internal switches pro- vide up to 97% efficiency. At light loads, the LM2653 enters a low power hysteretic or “sleep” mode to keep the efficiency high. In many applications, the efficiency still exceeds 80 load. A shutdown pin is available to disable the LM2653 and reduce the supply current to 7 µ ...

Page 2

Evaluation Board Design Designation CC2 (compensation) RC (compensation CDELAY RP D2 Typical PC Board Layout: (2X Size) www.national.com (Continued) TABLE 1. Parts List (Bill Of Materials) (Continued) 100pF ceramic capacitor 30kΩ, 5% resistor 1A Schottky diode, Motorola ...

Page 3

... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...

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