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參數(shù)資料
| 型號(hào)： | LP3958TLX |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 顯示驅(qū)動(dòng)器 |
| 英文描述： | Lighting Management Unit with High Voltage Boost Converter |
| 中文描述： | LED DISPLAY DRIVER, PBGA25 |
| 封裝： | 2.54 X 2.54 MM, 0.60 MM HEIGHT, 0.50 MM PITCH, LEAD FREE, MICRO SMD PACKAGE-25 |
| 文件頁數(shù)： | 22/28頁 |
| 文件大?。?/td> | 1091K |
| 代理商： | LP3958TLX |
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Recommended External Components
OUTPUT CAPACITOR, C
OUT
The output capacitor C
directly affects the magnitude of
the output ripple voltage. In general, the higher the value of
C
, the lower the output ripple magnitude. Multilayer ce-
ramic capacitors with low ESR are the best choice. At the
lighter loads, the low ESR ceramics offer a much lower V
ripple that the higher ESR tantalums of the same value. At
the higher loads, the ceramics offer a slightly lower V
ripple magnitude than the tantalums of the same value.
However, the dv/dt of the V
ripple with the ceramics is
much lower that the tantalums under all load conditions.
Capacitor voltage rating must be sufficient, 25V or greater is
recommended. Examples of suitable capacitors are: TDK
C3216X5R1E475K,
Panasonic
ECJMFB1E475K and ECJ4YB1E475K.
Some ceramic capacitors, especially those in small
packages, exhibit a strong capacitance reduction with
the increased applied voltage (DC bias effect). The ca-
pacitance value can fall below half of the nominal ca-
pacitance. Too low output capacitance can make the
boost converter unstable. Output capacitors DC bias
effect should be better than –50% at 18V.
ECJ3YB1E475K,
INPUT CAPACITOR, C
IN
The input capacitor C
directly affects the magnitude of the
input ripple voltage and to a lesser degree the V
ripple. A
higher value C
will give a lower V
ripple. Capacitor volt-
age rating must be sufficient, 10V or greater is recom-
mended.
OUTPUT DIODE, D
1
A schottky diode should be used for the output diode. Peak
repetitive current should be greater than inductor peak cur-
rent (800mA) to ensure reliable operation. Schottky diodes
with a low forward drop and fast switching speeds are ideal
for increasing efficiency in portable applications. Choose a
reverse breakdown voltage of the schottky diode signifi-
cantly larger (~30V) than the output voltage. Do not use
ordinary rectifier diodes, since slow switching speeds and
long recovery times cause the efficiency and the load regu-
lation to suffer. Example of suitable diode is: Central Semi-
conductor CMMSH1-40.
EMI FILTER COMPONENTS C
SW
, R
SW
EMI filter (R
and C
) on the SW pin can be used to
suppress EMI caused by fast switching. These components
should be as near as possible to the SW pin to ensure
reliable operation. 50V or greater voltage rating is recom-
mended for capacitor.
INDUCTOR, L
1
A 10uH shielded inductor is suggested for LP3958 boost
converter. The inductor should have a saturation current
rating higher than the rms current it will experience during
circuit operation (600mA). Less than 300m
ESR is sug-
gested for high efficiency and sufficient output current. Open
core inductors cause flux linkage with circuit components
and interfere with the normal operation of the circuit. This
should be avoided. For high efficiency, choose an inductor
with a high frequency core material such as ferrite to reduce
the core losses. To minimize radiated noise, use a toroid, pot
core or shielded core inductor. The inductor should be con-
nected to the SW pin as close to the IC as possible. Ex-
amples
of
suitable
inductors
100MR79, VLF4018BT-100MR90, VLF5014AT-100MR92,
Coilcraft LPS4018-103ML.
are:
TDK
VLF4012AT-
LIST OF RECOMMENDED EXTERNAL COMPONENTS
Symbol
C
VDD
C
VDDIO
C
VDDA
Symbol explanation
C between VDD1,2 and GND
C between VDDIO and GND
C between VDDA and GND
C between FB and GND
Maximum DC bias effect
@
18V
C between battery voltage and GND
L between SW and V
BAT
Saturation current
C between V
REF
and GND
R between I
KEY
and GND
R between I
RT
and GND
Rectifying diode (Vf
@
maxload)
Reverse voltage
Repetitive peak current
C in EMI filter
R in EMI filter
Value
100
100
1
Unit
nF
nF
μF
μF
%
μF
μH
mA
nF
k
k
V
V
mA
pF
Type
Ceramic, X7R / X5R
Ceramic, X7R / X5R
Ceramic, X7R / X5R
C
OUT
2 x 4.7 or 1 x 10
-50
10
10
600
100
8.2
82
0.3-0.5
30
800
100
390
Ceramic, X7R / X5R, tolerance +/-10%
C
IN
Ceramic, X7R / X5R
L
1
Shielded inductor, low ESR
C
VREF
R
KEY
R
RT
Ceramic, X7R / X5R
±
1%
±
1%
D
1
Schottky diode
C
SW
R
SW
LEDs
Ceramic, X7R / X5R, 50V
±
1%
User Defined
Note: See Application Note AN-1436 "Design and Programming Examples for Lighting Management Unit LP3958" for more
information on how to design with LP3958
L
www.national.com
22
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP3958TLX/NOPB | 功能描述:LED照明驅(qū)動(dòng)器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| LP395Z | 功能描述:兩極晶體管 - BJT RoHS:否 制造商:STMicroelectronics 配置: 晶體管極性:PNP 集電極—基極電壓 VCBO: 集電極—發(fā)射極最大電壓 VCEO:- 40 V 發(fā)射極 - 基極電壓 VEBO:- 6 V 集電極—射極飽和電壓: 最大直流電集電極電流: 增益帶寬產(chǎn)品fT: 直流集電極/Base Gain hfe Min:100 A 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PowerFLAT 2 x 2 |
| LP395Z | 制造商:Texas Instruments 功能描述:POWER TRANSISTOR TO-92-3 395 |
| LP395Z/LFT1 | 功能描述:兩極晶體管 - BJT RoHS:否 制造商:STMicroelectronics 配置: 晶體管極性:PNP 集電極—基極電壓 VCBO: 集電極—發(fā)射極最大電壓 VCEO:- 40 V 發(fā)射極 - 基極電壓 VEBO:- 6 V 集電極—射極飽和電壓: 最大直流電集電極電流: 增益帶寬產(chǎn)品fT: 直流集電極/Base Gain hfe Min:100 A 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PowerFLAT 2 x 2 |
| LP395Z/LFT2 | 功能描述:兩極晶體管 - BJT RoHS:否 制造商:STMicroelectronics 配置: 晶體管極性:PNP 集電極—基極電壓 VCBO: 集電極—發(fā)射極最大電壓 VCEO:- 40 V 發(fā)射極 - 基極電壓 VEBO:- 6 V 集電極—射極飽和電壓: 最大直流電集電極電流: 增益帶寬產(chǎn)品fT: 直流集電極/Base Gain hfe Min:100 A 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PowerFLAT 2 x 2 |
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