Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

LM2672 Datasheet(PDF) 18 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor. Click here to check the latest version.
Part No. LM2672
Description  SIMPLE SWITCHER Power Converter High Efficiency 1A Step-Down Voltage Regulator with Features
Download  25 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  NSC [National Semiconductor (TI)]
Direct Link  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM2672 Datasheet(HTML) 18 Page - National Semiconductor (TI)

Back Button LM2672 Datasheet HTML 14Page - National Semiconductor (TI) LM2672 Datasheet HTML 15Page - National Semiconductor (TI) LM2672 Datasheet HTML 16Page - National Semiconductor (TI) LM2672 Datasheet HTML 17Page - National Semiconductor (TI) LM2672 Datasheet HTML 18Page - National Semiconductor (TI) LM2672 Datasheet HTML 19Page - National Semiconductor (TI) LM2672 Datasheet HTML 20Page - National Semiconductor (TI) LM2672 Datasheet HTML 21Page - National Semiconductor (TI) LM2672 Datasheet HTML 22Page - National Semiconductor (TI) Next Button
Zoom Inzoom in Zoom Outzoom out
 18 / 25 page
background image
LM2672 Series Buck Regulator
Design Procedure (Adjustable
Output)
PROCEDURE (Adjustable Output Voltage Version)
EXAMPLE (Adjustable Output Voltage Version)
To simplify the buck regulator design procedure, National
Semiconductor is making available computer design software to
be used with the SIMPLE SWITCHER line of switching
regulators. LM267X Made Simple version 1.0 is available on
Windows 3.1, NT, or 95 operating systems.
Given:
Given:
V
OUT = Regulated Output Voltage
V
OUT = 20V
V
IN(max) = Maximum Input Voltage
V
IN(max) = 28V
I
LOAD(max) = Maximum Load Current
I
LOAD(max) = 1A
F = Switching Frequency (Fixed at a nominal 260 kHz).
F = Switching Frequency (Fixed at a nominal 260 kHz).
1. Programming Output Voltage (Selecting R
1 and R2,as
shown in Figure 3)
Use the following formula to select the appropriate resistor
values.
1. Programming Output Voltage (Selecting R
1 and R2,as
shown in Figure 3)
Select R
1 to be 1 k
Ω, 1%. Solve for R
2.
where V
REF = 1.21V
Select a value for R
1 between 240
Ω and 1.5 kΩ. The lower
resistor values minimize noise pickup in the sensitive feedback
pin. (For the lowest temperature coefficient and the best stability
with time, use 1% metal film resistors.)
R
2 =1k
Ω (16.53 − 1) = 15.53 kΩ, closest 1% value is 15.4 kΩ.
R
2 = 15.4 k
Ω.
2. Inductor Selection (L1)
A. Calculate the inductor Volt
microsecond constant E T
(V
µs), from the following formula:
2. Inductor Selection (L1)
A. Calculate the inductor Volt
microsecond constant (E T),
where V
SAT=internal switch saturation voltage=0.25V and
V
D = diode forward voltage drop = 0.5V
B. Use the E
T value from the previous formula and match it
with the E
T number on the vertical axis of the Inductor Value
Selection Guide shown in Figure 7.
B. E
T = 21.6 (V µs)
C. On the horizontal axis, select the maximum load current.
C. I
LOAD(max) = 1A
D. Identify the inductance region intersected by the E
T value
and the Maximum Load Current value. Each region is identified
by an inductance value and an inductor code (LXX).
D. From the inductor value selection guide shown in Figure 7,
the inductance region intersected by the 21.6 (V
µs) horizontal
line and the 1A vertical line is 68 µH, and the inductor code is
L30.
E. Select an appropriate inductor from the four manufacturer’s
part numbers listed in Figure 8. For information on the different
types of inductors, see the inductor selection in the fixed output
voltage design procedure.
E. From the table in Figure 8, locate line L30, and select an
inductor part number from the list of manufacturers’ part
numbers.
3. Output Capacitor SeIection (C
OUT)
A. Select an output capacitor from the capacitor code selection
guide in Figure 16. Using the inductance value found in the
inductor selection guide, step 1, locate the appropriate capacitor
code corresponding to the desired output voltage.
3. Output Capacitor SeIection (C
OUT)
A. Use the appropriate row of the capacitor code selection
guide, in Figure 16. For this example, use the 15–20V row. The
capacitor code corresponding to an inductance of 68 µH is C20.
www.national.com
18


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25 


Datasheet Download

Go To PDF Page

Related Electronics Part Number

Part No.DescriptionHtml ViewManufacturer
LM2671 SIMPLE SWITCHER Power Converter High Efficiency 500mA Step-Down Voltage Regulator with Features 1  2  3  4  5  More National Semiconductor (TI)
LM2590HV SIMPLE SWITCHER Power Converter 150 kHz 1A Step-Down Voltage Regulator with Features 1  2  3  4  5  More National Semiconductor (TI)
LM2593HV SIMPLE SWITCHER Power Converter 150 kHz 2A Step-Down Voltage Regulator with Features 1  2  3  4  5  More National Semiconductor (TI)
LM2597 SIMPLE SWITCHER Power Converter 150 kHz 0.5A Step-Down Voltage Regulator with Features 1  2  3  4  5  More National Semiconductor (TI)
LM2598 SIMPLE SWITCHER Power Converter 150 kHz 1A Step-Down Voltage Regulator with Features 1  2  3  4  5  More National Semiconductor (TI)
LM2674 SIMPLE SWITCHER Power Converter High Efficiency 500 mA Step-Down Voltage Regulator 1  2  3  4  5  More National Semiconductor (TI)
LM2599 SIMPLE SWITCHER Power Converter 150 kHz 3A Step-Down Voltage Regulator with Features 1  2  3  4  5  More National Semiconductor (TI)
LM2675 SIMPLE SWITCHER Power Converter High Efficiency 1A Step-Down Voltage Regulator 1  2  3  4  5  More National Semiconductor (TI)
LM2670 SIMPLE SWITCHER High Efficiency 3A Step-Down Voltage Regulator with Sync 1  2  3  4  5  More National Semiconductor (TI)
LM2677 SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator with Sync 1  2  3  4  5  More National Semiconductor (TI)

Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn