參數(shù)資料
型號: LM2598T-3.3
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: SIMPLE SWITCHER Power Converter 150 kHz 1A Step-Down Voltage Regulator, with Features
中文描述: 2.6 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, PSFM7
封裝: BENT STAGGERED, TO-220, 7 PIN
文件頁數(shù): 10/33頁
文件大?。?/td> 847K
代理商: LM2598T-3.3
Test Circuit and Layout Guidelines
(Continued)
As in any switching regulator, layout is very important. Rap-
idly switching currents associated with wiring inductance can
generate voltage transients which can cause problems. For
minimal inductance and ground loops, the wires indicated by
heavy lines should be wide printed circuit traces and
should be kept as short as possible.
For best results,
external components should be located as close to the
switcher lC as possible using ground plane construction or
single point grounding.
LM2598 Series Buck Regulator Design Procedure (Fixed Output)
If
open core inductors are used,
special care must be
taken as to the location and positioning of this type of induc-
tor. Allowing the inductor flux to intersect sensitive feedback,
lC groundpath and C
OUT
wiring can cause problems.
When using the adjustable version, special care must be
taken as to the location of the feedback resistors and the
associated wiring. Physically locate both resistors near the
IC, and route the wiring away from the inductor, especially an
open core type of inductor. (See application section for more
information.)
PROCEDURE (Fixed Output Voltage Version)
EXAMPLE (Fixed Output Voltage Version)
Given:
Given:
V
OUT
= Regulated Output Voltage (3.3V, 5V or 12V)
V
OUT
= 5V
V
IN
(max) = Maximum DC Input Voltage
V
IN
(max) = 12V
I
LOAD
(max) = Maximum Load Current
I
LOAD
(max) = 1A
1. Inductor Selection (L1)
1. Inductor Selection (L1)
A.
Select the correct inductor value selection guide from
Figures Figure 4 Figure 5 or Figure 6 (Output voltages of
3.3V, 5V, or 12V respectively.) For all other voltages, see the
design procedure for the adjustable version.
A.
Use the inductor selection guide for the 5V version shown
in Figure 5
B.
From the inductor value selection guide, identify the in-
ductance region intersected by the Maximum Input Voltage
line and the Maximum Load Current line. Each region is
identified by an inductance value and an inductor code
(LXX).
B.
From the inductor value selection guide shown in Figure 5
the inductance region intersected by the 12V horizontal line
and the 1A vertical line is 68 μH, and the inductor code is
L30.
C.
Select an appropriate inductor from the four manufactur-
er’s part numbers listed in Figure 8
C.
The inductance value required is 68 μH. From the table in
Figure 8 go to the L30 line and choose an inductor part
number from any of the four manufacturers shown. (In most
instance, both through hole and surface mount inductors are
available.)
2. Output Capacitor Selection (C
OUT
)
2. Output Capacitor Selection (C
OUT
)
A.
In the majority of applications, low ESR (Equivalent Series
Resistance) electrolytic capacitors between 47 μF and 330
μF and low ESR solid tantalum capacitors between 56 μF
and 270 μF provide the best results. This capacitor should be
located close to the IC using short capacitor leads and short
copper traces. Do not use capacitors larger than 330 μF.
For additional information, see section on output capaci-
tors in application information section.
A. See section on output capacitors in application infor-
mation section.
L
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LM2598T-5.0/NOPB 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
LM2598T-ADJ 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
LM2598T-ADJ/NOPB 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
LM2599S-12 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT