LM2593HVEVAL National Semiconductor, LM2593HVEVAL Datasheet

LM2593HVEVAL

Manufacturer Part Number

LM2593HVEVAL

Description

BOARD EVALUATION LM2593

Manufacturer

National Semiconductor

Series

SIMPLE SWITCHER®r

Datasheets

1.LM2593HVS-ADJNOPB.pdf (21 pages)

2.LM2593HVEVAL.pdf (4 pages)

Specifications of LM2593HVEVAL

Main Purpose

DC/DC, Step Down

Outputs And Type

1, Non-Isolated

Voltage - Output

12V

Current - Output

Voltage - Input

4.5 ~ 60V

Regulator Topology

Buck

Frequency - Switching

150kHz

Board Type

Fully Populated

Utilized Ic / Part

LM2593

Lead Free Status / RoHS Status

Not applicable / Not applicable

Power - Output

Current page: 1 of 4
Download datasheet (220Kb)

LM2593HV Evaluation

Board

Specifications of the Board

The board is designed for a nominal DC input of 48V, but can

safely withstand up to 60V. The regulated DC output is 12V

at a maximum load current of 2A. It uses the Adjustable

Version of the LM2593HV in 7 lead Surface Mount Package

(TO263). Relying on careful layout, it eliminates the need for

a snubber across the diode and uses a minimum number of

components. It has shutdown capability and error flag output

available on the board. It incorporates soft-start and delayed

output error signaling and has an overall efficiency higher

than 85%.

The board uses no external heatsinks, or through-hole parts

and is therefore suitable for a fully automatic production

process. It requires only 1.7 x 2.0 x 0.7 cu. inches of space.

The printed circuit board is standard 1.6 mm thick (62 mils)

‘

plating, totaling a little over 1 oz of copper (“1 oz” is 1.4

mils/35 µm thick). The traces have been left unmasked to

allow solder to deposit on the traces during reflow, so as to

aid thermal dissipation. The converter is designed for con-

tinuous operation at rated load under natural convection up

to a maximum ambient of 40˚C.

Component Selection

We set

INDUCTOR

We define ‘D’ as the Duty Cycle and ‘r’ the ripple current ratio

∆I/I

terms and equations used here.

We choose r to be 0.3 here as per the design procedure

inductor nomographs in the LM2593HV datasheet as well as

the guidelines in the referenced Application Note. ‘r’ is re-

lated to the inductance through the equation

where ‘Et’ is the applied Voltµsecs, I

load in Amps, and L is the inductance in µH.

The Duty Cycle is

where V

is the drop across the switch when it is ON, plus any para-

sitics (≅1.5V). So

⁄

= 2A

oz’ double-sided FR4 laminate, with additional cooper

= 12V

= 48V

. See Application Note AN-1197 for more details on the

is the diode forward voltage drop (≅0.5V), and V

is the maximum rated

AN200256

National Semiconductor

Application Note 1207

Sanjaya Maniktala

July 2001

The switch ON-time is

So the Voltµseconds ‘Et’ is

Et = (V

Et = 61.1 Vµs

Estimated inductance is therefore

L = 101.8 µH

The first pass selection of the inductor is usually on the basis

of the inductance calculated above and the max load cur-

rent. But if the Input Voltage exceeds 40V, as it does here,

we need to evaluate the inductor further to ensure that the

converter

overloaded/shorted. Here we have chosen a 100 µH/1.8A

drum core type (large inherent air gap) from Coilcraft, which

saturates above 3A. It is designed for a 40˚C rise in tem-

perature at a maximum ambient of 85˚C. We have accepted

its use at a load current slightly higher than its continuous

rating since the maximum ambient temperature for the

demo-board is only 40˚C not 85˚C, and since we also know

it does not saturate at the maximum load current.

INPUT CAPACITOR

The Voltage rating of the input capacitor must be higher than

the DC Input. Tantalum capacitors were not considered suit-

able here due to their 50V maximum rating, and their inher-

ent surge current limitations (which are always of concern

especially at high input voltages). We have chosen a 63V

aluminum electrolytic SMT capacitor from Panasonic, sized

to handle the RMS current as calculated below:

The capacitor we chose is 100 µF with an RMS current rating

of 1.02A at 100 kHz.

= 1.77 µs

− V

withstands

− V

) x t

damage

= (48−1.5−12) x 1.77 Vµs

the

www.national.com

outputs

are

Related parts for LM2593HVEVAL

LM2593HVEVAL Summary of contents

Page 1

... The Duty Cycle is where V is the diode forward voltage drop (≅0.5V), and the drop across the switch when it is ON, plus any para- sitics (≅1.5V). So © 2002 National Semiconductor Corporation National Semiconductor Application Note 1207 Sanjaya Maniktala July 2001 The switch ON-time 1.77 µ ...

Page 2

Component Selection OUTPUT CAPACITOR We have chosen a capacitor type similar to the input capaci- tor mainly for logistic reasons. It was initially sized simply to handle the RMS current as calculated below, and with a voltage rating just higher ...

Page 3

... C1 100 µF/63V C2, C3, C4 0.1 µF/100V C5 47 µF/16V R1 2.37K/1% R2, R3 21K/1% FIGURE 2. Top Side (Component Side) of PCB TABLE 1. Bill of Material Manufacturer Part Number National Semiconductor LM2593HVS-ADJ International Rectifier MBRS360TR Coilcraft DO5022-104 Panasonic EEVFC1J101Q Vishay-Vitramon VJ1206Y104KXBA Panasonic EEVFK1C470P Vishay CRCW12062371F Vishay ...

Page 4

... 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 ...

Related keywords

lm2594
lm2593hveval
lm2593hv
lm2593
LM2593HVEVAL datasheet
LM2593HVEVAL data sheet
LM2593HVEVAL pdf datasheet
LM2593HVEVAL component
LM2593HVEVAL part
LM2593HVEVAL distributor
LM2593HVEVAL RoHS
LM2593HVEVAL datasheet download