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參數(shù)資料
| 型號(hào)： | LP3996SD-0833 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類(lèi)： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | Dual Linear Regulator with 300mA and 150mA Outputs and Power-On-Reset |
| 中文描述： | DUAL OUTPUT, FIXED POSITIVE LDO REGULATOR, DSO10 |
| 封裝： | 3 X 3 MM, LEAD FREE, LLP-10 |
| 文件頁(yè)數(shù)： | 14/16頁(yè) |
| 文件大小： | 871K |
| 代理商： | LP3996SD-0833 |
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Application Hints
(Continued)
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.
ENABLE CONTROL
The LP3996 features active high enable pins for each regu-
lator, EN1 and EN2, which turns the corresponding LDO off
when pulled low. The device outputs are enabled when the
enable lines are set to high. When not enabled the regulator
output is off and the device typically consumes 2nA.
If the application does not require the Enable switching
feature, one or both enable pins should be tied to V
IN
to keep
the regulator output permanently on.
To ensure proper operation, the signal source used to drive
the enable inputs must be able to swing above and below the
specified turn-on / off voltage thresholds listed in the Electri-
cal Characteristics section under V
IL
and V
IH
.
POWER-ON-RESET
The POR pin is an open-drain output which will be set to Low
whenever the output of LDO2 falls out of regulation to ap-
proximately 90% of its nominal value. An external pull-up
resistor, connected to V
or V
, is required on this pin.
During start-up, or whenever a fault condition is removed,
the POR flag will return to the High state after the output
reaches approximately 96% of its nominal value. By con-
necting a capacitor from the SET pin to GND, a delay to the
rising condition of the POR flag may be introduced. The
delayed signal may then be used as a Power-on -Reset for a
microprocessor within the user’s application.
The duration of the delay is determined by the time to charge
the delay capacitor to a threshold voltage of 1.25V at 1.2μA
from the SET pin as in the formula below.
20145841
A 0.1μF capacitor will introduce a delay of approximately
100ms.
BYPASS CAPACITOR
The internal voltage reference circuit of the LP3996 is con-
nected to the C
pin via a high value internal resistor. An
external capacitor, connected to this pin, forms a low-pass
filter which reduces the noise level on both outputs of the
device. There is also some improvement in PSSR and line
transient performance. Internal circuitry ensures rapid charg-
ing of the C
capacitor during start-up.A10nF, high quality
ceramic capacitor with either NPO or COG dielectric is rec-
ommended due to their low leakage characteristics and low
noise performance.
SAFE AREA OF OPERATION
Due consideration should be given to operating conditions to
avoid excessive thermal dissipation of the LP3996 or trigger-
ing its thermal shutdown circuit. When both outputs are
enabled,
the
total
P
D(LDO1)
+ P
D(LDO2)
Where P
D
= (V
IN
- V
OUT
) x I
OUT
for each
LDO.
In general, device options which have a large difference in
output voltage will dissipate more power when both outputs
are enabled, due to the input voltage required for the higher
output voltage LDO. In such cases, especially at elevated
ambient temperature, it may not be possible to operate both
outputs at maximum current at the same time.
dissipation
will
be
L
www.national.com
14
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP3996SD-0833/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(dòng)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(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP3996SD-1018/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(dòng)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(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP3996SD-1525 | 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(dòng)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(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP3996SD-1525/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(dòng)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(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP3996SD-1833/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(dòng)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(lèi)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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