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參數(shù)資料
| 型號： | LP5900TL-1.8 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | 128 x 64 pixel format, LED Backlight available |
| 中文描述： | 1.8 V FIXED POSITIVE REGULATOR, PBGA4 |
| 封裝： | 1.057 X 1.083 MM, MICRO, SMD-4 |
| 文件頁數(shù)： | 9/10頁 |
| 文件大小： | 645K |
| 代理商： | LP5900TL-1.8 |
Application Hints
(Continued)
This capacitor must be located a distance of not more than 1
cm from the input pin and returned to a clean analogue
ground.Any good quality ceramic, tantalum, or film capacitor
may be used at the input.
Important:
To ensure stable operation it is essential that
good PCB practices are employed to minimize ground im-
pedance and keep input inductance low. If these conditions
cannot be met, or if long leads are to be used to connect the
battery or other power source to the LP5900, then it is
recommended to increase the input capacitor to at least
2.2μF. Also, tantalum capacitors can suffer catastrophic fail-
ures due to surge current when connected to a low-
impedance source of power (like a battery or a very large
capacitor). If a tantalum capacitor is used at the input, it must
be guaranteed by the manufacturer to have a surge current
rating sufficient for the application. There are no require-
ments for the ESR (Equivalent Series Resistance) on the
input capacitor, but tolerance and temperature coefficient
must be considered when selecting the capacitor to ensure
the capacitance will remain 0.47 μF
±
30% over the entire
operating temperature range.
OUTPUT CAPACITOR
The LP5900 is designed specifically to work with very small
ceramic output capacitors. A ceramic capacitor (dielectric
types X5R or X7R) in the 0.47 μF to 10 μF range, and with
ESR between 5 m
to 500 m
, is suitable in the LP5900
application circuit. For this device the output capacitor
should be connected between the V
OUT
pin and a good
ground connection and should be mounted within 1 cm of the
device.
It may also be possible to use tantalum or film capacitors at
the device output, V
, but these are not as attractive for
reasons of size and cost (see the section Capacitor Charac-
teristics).
The output capacitor must meet the requirement for the
minimum value of capacitance and have an ESR value that
is within the range 5 m
to 500 m
for stability.
CAPACITOR CHARACTERISTICS
The LP5900 is designed to work with ceramic capacitors on
the input and output to take advantage of the benefits they
offer. For capacitance values in the range of 0.47 μF to 4.7
μF, ceramic capacitors are the smallest, least expensive and
have the lowest ESR values, thus making them best for
eliminating high frequency noise. The ESR of a typical 0.47
μF ceramic capacitor is in the range of 20 m
to 40 m
,
which easily meets the ESR requirement for stability for the
LP5900.
The temperature performance of ceramic capacitors varies
by type and manufacturer. Most large value ceramic capaci-
tors (
≥
2.2 μF) are manufactured with Z5U or Y5V tempera-
ture characteristics, which results in the capacitance drop-
ping by more than 50% as the temperature goes from 25C
to 85C.
A better choice for temperature coefficient in a ceramic
capacitor is X7R. This type of capacitor is the most stable
and holds the capacitance within
±
15% over the tempera-
ture range. Tantalum capacitors are less desirable than ce-
ramic for use as output capacitors because they are more
expensive when comparing equivalent capacitance and volt-
age ratings in the 0.47 μF to 4.7 μF range.
Another important consideration is that tantalum capacitors
have higher ESR values than equivalent size ceramics. This
means that while it may be possible to find a tantalum
capacitor with an ESR value within the stable range, it would
have to be larger in capacitance (which means bigger and
more costly) than a ceramic capacitor with the same ESR
value. It should also be noted that the ESR of a typical
tantalum will increase about 2:1 as the temperature goes
from 25C down to 40C, so some guard band must be
allowed.
NO-LOAD STABILITY
The LP5900 will remain stable and in regulation with no
external load.
ENABLE CONTROL
The LP5900 may be switched ON or OFF by a logic input at
the ENABLE pin, V
. A high voltage at this pin will turn the
device on. When the enable pin is low, the regulator output is
off and the device typically consumes 3 nA. If the application
does not require the shutdown feature, the V
pin should
be tied to V
IN
to keep the regulator output permanently on.
A 1M
pulldown resistor ties the V
input to ground, this
ensures that the device will remain off when the enable pin is
left open circuit. To ensure proper operation, the signal
source used to drive the V
EN
input must be able to swing
above and below the specified turn-on/off voltage thresholds
listed in the Electrical Characteristics section under V
IL
and
V
IH
.
micro SMD MOUNTING
The micro SMD package requires specific mounting tech-
niques, which are detailed in National Semiconductor Appli-
cation Note AN-1112.
For best results during assembly, alignment ordinals on the
PC board may be used to facilitate placement of the micro
SMD device.
micro SMD LIGHT SENSITIVITY
Exposing the micro SMD device to direct light may cause
incorrect operation of the device. Light sources such as
halogen lamps can affect electrical performance if they are
situated in proximity to the device.
Light with wavelengths in the red and infra-red part of the
spectrum have the most detrimental effect thus the fluores-
cent lighting used inside most buildings has very little effect
on performance.
L
www.national.com
9
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LP5900TL-2.0 | 128 x 64 pixel format, LED Backlight available |
| LP5900TL-2.2 | 128 x 64 pixel format, LED Backlight available |
| LP5900 | Ultra Low Noise, 100 mA Linear Regulator for RF/Analog Circuits Requires No Bypass Capacitor |
| LP5900TL-2.5 | 128 x 64 pixel format, LED Backlight available |
| LP5900TL-2.8 | 128 x 64 pixel format, LED Backlight available |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP5900TL-2.0 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Ultra Low Noise, 100 mA Linear Regulator for RF/Analog Circuits Requires No Bypass Capacitor |
| LP5900TL-2.0/NOPB | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP5900TL-2.0EV | 功能描述:電源管理IC開發(fā)工具 LP5900 2.0V EVAL BOARD RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| LP5900TL-2.1 | 制造商:Texas Instruments 功能描述:LDO Regulator Pos 2.1V 0.15A 4-Pin DSBGA T/R |
| LP5900TL-2.1/NOPB | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
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