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參數(shù)資料
| 型號： | LP8358 |
| 廠商： | National Semiconductor Corporation |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | 150mA, UCap, Low Dropout Voltage Regulator with Power Good |
| 中文描述： | 150mA的，開普，低壓差線性穩(wěn)壓器的電源良好 |
| 文件頁數(shù)： | 9/10頁 |
| 文件大?。?/td> | 508K |
| 代理商： | LP8358 |
Application Notes
The LP8358 is a linear regulator with power good output
designed to be used with a low ESR, low cost ceramic
capacitors.
EXTERNAL CAPACITORS
The LP8358 regulator requires an output capacitor to main-
tain stability. The capacitor must be at least 1μF or greater.
The capacitor can be low-ESR ceramic chip capacitor, how-
ever for improved capacitance over temperature, tantalum
capacitors can be used.
A1μF input capacitor is recommend when the supply capaci-
tance is more than 10 inches away from the device, or when
the supply is a battery.
X7R dielectric ceramic capacitors are recommended be-
cause of their temperature performance. X7R-type capacitor
change capacitance by 15% over their operating tempera-
ture range and are the most stable type of ceramic capaci-
tors. Z5U and Y5V dielectric capacitors change value by as
much 50% and 60% respectively over their operating tem-
perature range. To use a ceramic chip capacitor with Y5V
dielectric, the value must be much higher than a X7/R ce-
ramic or a tantalum capacitor to ensure the same minimum
capacitance value over the operating temperature range.
Tantalum capacitors have a very stable dielectric (10% over
their operating temperature range) and can also be used
with this device.
ENABLE/SHUTDOWN
The LP8358 has an active high enable pin that allows the
regulator to be disabled. Applying a Logic Level low (
<
0.4 V)
to the Shutdown pin will cause the output to turn off, in this
state current consumed by the regulator goes nearly to zero.
Applying a Logic Level high (
>
2.0V) enables the output
voltage. The enable/shutdown pin must not be left floating; a
floating enable pin may cause an indeterminate state on the
output.
ACTIVE SHUTDOWN
The LP8358 is designed with a N-channel MOSFET that
acts as a shutdown clamp. The N-channel turns on when the
device is disabled to allow the output capacitor and load to
discharge
POWER GOOD
The power good output is an open-drain output with extreme
low R
. It is designed essentially to work as a power-on
reset generator once the regulated voltage is up and/ or a
fault condition. When a fault condition occurs, the output of
the power good pin goes low. The power good output comes
back up once the output has reached 97% of its nominal
value and 1ms to 5ms delay has passed , see timing dia-
gram.
The LP8358 internal circuit monitors overcurrent, tempera-
ture and falling output voltage. If one of these conditions is
flagged this indicates a fault condition.
The flagged condition output is fed into an onchip delay
circuit that drives the open drain output transistor.
TRANSIENT RESPONSE
The LP8358 implements a unique output stage to dramati-
cally improve transient response recovery time. The output is
a totem-pole configuration with a P-channel MOSFET pass
device and a N-channel MOSFET clamp. The N-channel
clamp is a significantly smaller device that prevents the
output voltage from overshooting when a heavy load is
removed. This feature helps to speed up the transient re-
sponse by significantly decreasing transient response recov-
ery time during the transition from heavy load to light load.
THERMAL BEHAVIOR
The LP8358 regulator has internal thermal shutdown to pro-
tect the device from over heating. Under all operating con-
ditions, the maximum junction temperature of the LP8358
must be below 125C. Maximum power dissipation can be
calculated based on the output current and the voltage drop
across the part. The maximum power dissipation is
P
D(MAX)
= (T
J(MAX)
–T
A
)/
θ
JA
θ
is the junction-to-ambient thermal resistance, 235C/W
for the LP8358 in the SOT23-5 package. T
A
is the maximum
ambient temperature T
J(MAX)
is the maximum junction tem-
perature of the die, 125C.
When operating the LP8358 at room temperature, the maxi-
mum power dissipation is 425mW.
The actual power dissipated by the regulator is
P
D
= (V
IN
–V
OUT
)I
L
+V
IN
I
GND
Substituting P
D(MAX)
, determined above, for P
D
and solving
for the operating condition that is critical to the application
will give the maximum operating condition for the regulator
circuit. To prevent the device from entering thermal shut-
down, maximum power dissipation cannot be exceeded.
L
www.national.com
9
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| LP8358A-1.2 E WAF | 制造商:Texas Instruments 功能描述: |
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| LP8358MF-1.2 | 制造商:Texas Instruments 功能描述:IC V REG LDO 0.15A 1.2V SMD 8358 |
| LP8358MF-1.2/NOPB | 功能描述:IC REG LDO 1.2V .15A SOT23-5 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):正，固定式 輸出電壓:4V 輸入電壓:最高 16V 電壓 - 壓降（標(biāo)準(zhǔn)）:0.28V @ 150mA 穩(wěn)壓器數(shù)量:1 電流 - 輸出:150mA 電流 - 限制（最?。?- 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:5-VFBGA 供應(yīng)商設(shè)備封裝:5-uSMD 包裝:Digi-Reel® 其它名稱:LP2985AIBP-4.0DKR |
| LP8358MFX-1.2 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:150mA, UCap, Low Dropout Voltage Regulator with Power Good |
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