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參數(shù)資料
| 型號(hào)： | LX8587-33CDD |
| 廠(chǎng)商： | MICROSEMI CORP-ANALOG MIXED SIGNAL GROUP |
| 元件分類(lèi)： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | 3A LOW DROPOUT POSITIVE REGULATORS |
| 中文描述： | 3.3 V FIXED POSITIVE LDO REGULATOR, 1.3 V DROPOUT, PSSO3 |
| 封裝： | ROHS COMPLIANT, PLASTIC, TO-263, 3 PIN |
| 文件頁(yè)數(shù)： | 5/8頁(yè) |
| 文件大?。?/td> | 211K |
| 代理商： | LX8587-33CDD |
3A L
OW
D
ROPOUT
P
OSITIVE
R
E G U L ATORS
LX8587-xx/8587A-xx
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
5
Copyright 1998
Rev. 1.2 3/98
P
R O D U C T I O N
D
A T A
S
H E E T
A P P L I C AT I O N N O T E S
The LX8587/87A series ICs are easy to use Low-Dropout (LDO)
voltage regulators. They have all of the standard self-protection
features expected of a voltage regulator: short circuit protection,
safe operating area protection and automatic thermal shutdown if
the device temperature rises above approximately 165°C.
Use of an output capacitor is REQUIRED with the LX8587/87A
series. Please see the table below for recommended minimum
capacitor values.
These regulators offer a more tightly controlled reference voltage
tolerance and superior reference stability when measured against
the older pin-compatible regulator types that they replace.
STABILITY
The output capacitor is part of the regulator’s frequency compen-
sation system. Many types of capacitors are available, with different
capacitance value tolerances, capacitance temperature coefficients,
and equivalent series impedances. For all operating conditions,
connection of a 220μF aluminum electrolytic capacitor or a 47μF
solid tantalum capacitor between the output terminal and ground
will guarantee stable operation.
If a bypass capacitor is connected between the output voltage
adjust (ADJ) pin and ground, ripple rejection will be improved
(please see the section entitled “
RIPPLE REJECTION
”). When ADJ
pin bypassing is used, the required output capacitor value increases.
Output capacitor values of 220μF (aluminum) or 47μF (tantalum)
provide for all cases of bypassing the ADJ pin. If an ADJ pin bypass
capacitor is not used, smaller output capacitor values are adequate.
The table below shows recommended minimum capacitance values
for stable operation.
INPUT
10μF
10μF
OUTPUT
ADJ
None
15μF
15μF Tantalum, 100μF Aluminum
47μF Tantalum, 220μF Aluminum
In order to ensure good transient response from the power supply
system under rapidly changing current load conditions, designers
generally use several output capacitors connected in parallel. Such
an arrangement serves to minimize the effects of the parasitic
resistance (ESR) and inductance (ESL) that are present in all
capacitors. Cost-effective solutions that sufficiently limit ESR and
ESL effects generally result in total capacitance values in the range
of hundreds to thousands of microfarads, which is more than
adequate to meet regulator output capacitor specifications. Output
capacitance values may be increased without limit.
The circuit shown in Figure 1 can be used to observe the transient
response characteristics of the regulator in a power system under
changing loads. The effects of different capacitor types and values
on transient response parameters, such as overshoot and under-
shoot, can be quickly compared in order to develop an optimum
solution.
RECOMMENDED CAPACITOR VALUES
FIGURE 1
— Dynamic Input And Output Test
LX8587/87A
Power Supply
OUT
IN
ADJ
Star Ground
1 sec
10ms
R
DSON
<< R
L
Full Load
(Smaller resistor)
Minumum Load
(Larger resistor)
OVERLOAD RECOVERY
Like almost all IC power regulators, the LX8587/87A regulators are
equipped with Safe Operating Area (SOA) protection. The SOA
circuit limits the regulator's maximum output current to progres-
sively lower values as the input-to-output voltage difference
increases. By limiting the maximum output current, the SOA circuit
keeps the amount of power that is dissipated in the regulator itself
within safe limits for all values of input-to-output voltage within the
operating range of the regulator. The LX8587/87A SOA protection
system is designed to be able to supply some output current for all
values of input-to-output voltage, up to the device breakdown
voltage.
Under some conditions, a correctly operating SOA circuit may
prevent a power supply system from returning to regulated
operation after removal of an intermittent short circuit at the output
of the regulator. This is a normal mode of operation which can be
seen in most similar products, including older devices such as 7800
series regulators. It is most likely to occur when the power system
input voltage is relatively high and the load impedance is relatively
low.
When the power system is started “cold”, both the input and
output voltages are very close to zero. The output voltage closely
follows the rising input voltage, and the input-to-output voltage
difference is small. The SOA circuit therefore permits the regulator
to supply large amounts of current as needed to develop the
designed voltage level at the regulator output. Now consider the
case where the regulator is supplying regulated voltage to a resistive
load under steady state conditions. A moderate input-to-output
voltage appears across the regulator but the voltage difference is
small enough that the SOA circuitry allows sufficient current to flow
through the regulator to develop the designed output voltage across
the load resistance. If the output resistor is short-circuited to ground,
the input-to-output voltage difference across the regulator suddenly
becomes larger by the amount of voltage that had appeared across
the load resistor. The SOA circuit reads the increased input-to-
output voltage, and cuts back the amount of current that it will
permit the regulator to supply to its output terminal. When the short
circuit across the output resistor is removed, all the regulator output
current will again flow through the output resistor. The maximum
current that the regulator can supply to the resistor will be limited
by the SOA circuit, based on the large input-to-output voltage across
the regulator at the time the short circuit is removed from the output.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LX8587-33CDDT | 制造商:MICROSEMI 制造商全稱(chēng):Microsemi Corporation 功能描述:Positive Fixed Voltage Regulator |
| LX8587-33CP | 功能描述:IC REG LDO 3.3V 3A TO220 RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線(xiàn)性 系列:- 標(biāo)準(zhǔn)包裝:3,000 系列:- 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):正，固定式 輸出電壓:3.8V 輸入電壓:最高 16V 電壓 - 壓降（標(biāo)準(zhǔn)）:0.3V @ 80mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:80mA 電流 - 限制（最?。?- 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應(yīng)商設(shè)備封裝:SOT-23-5 包裝:帶卷 (TR) 其它名稱(chēng):MIC5203-3.8BM5TRMIC5203-3.8BM5TR-ND |
| LX8587A-00 | 制造商:MICROSEMI 制造商全稱(chēng):Microsemi Corporation 功能描述:3A LOW DROPOUT POSITIVE REGULATORS |
| LX8587A-00CDD | 功能描述:IC REG LDO ADJ 3A TO263 RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線(xiàn)性 系列:- 標(biāo)準(zhǔn)包裝:3,000 系列:- 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):正，固定式 輸出電壓:3.8V 輸入電壓:最高 16V 電壓 - 壓降（標(biāo)準(zhǔn)）:0.3V @ 80mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:80mA 電流 - 限制（最?。?- 工作溫度:-40°C ~ 125°C 安裝類(lèi)型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應(yīng)商設(shè)備封裝:SOT-23-5 包裝:帶卷 (TR) 其它名稱(chēng):MIC5203-3.8BM5TRMIC5203-3.8BM5TR-ND |
| LX8587A-00CDDT | 制造商:MICROSEMI 制造商全稱(chēng):Microsemi Corporation 功能描述:Positive Adjustable Voltage Regulator |
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