- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄358906 > LP2954IM (NATIONAL SEMICONDUCTOR CORP) 5V and Adjustable Micropower Low-Dropout Voltage Regulators PDF資料下載
參數(shù)資料
| 型號(hào)： | LP2954IM |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | 5V and Adjustable Micropower Low-Dropout Voltage Regulators |
| 中文描述： | 1.23 V-29 V ADJUSTABLE POSITIVE LDO REGULATOR, 0.8 V DROPOUT, PDSO8 |
| 封裝： | SO-8 |
| 文件頁數(shù)： | 9/13頁 |
| 文件大?。?/td> | 336K |
| 代理商： | LP2954IM |
Application Hints
(Continued)
OUTPUT ISOLATION
The regulator output can be left connected to an active volt-
age source (such as a battery) with the regulator input power
turned off,
as long as the regulator ground pin is con-
nected to ground
. If the ground pin is left floating,
damage
to the regulator can occur
if the output is pulled up by an
external voltage source.
REDUCING OUTPUT NOISE
In reference applications it may be advantageous to reduce
theAC noise present on the output. One method is to reduce
regulator bandwidth by increasing output capacitance. This
is relatively inefficient, since large increases in capacitance
are required to get significant improvement.
Noise can be reduced more effectively by a bypass capacitor
placed across R1 (refer to Figure 2). The formula for select-
ing the capacitor to be used is:
This gives a value of about 0.1 μF. When this is used, the
output capacitor must be 6.8 μF (or greater) to maintain sta-
bility. The 0.1 μF capacitor reduces the high frequency gain
of the circuit to unity, lowering the output noise from 260 μV
to 80 μV using a 10 Hz to 100 kHz bandwidth. Also, noise is
no longer proportional to the output voltage, so improve-
ments are more pronounced at high output voltages.
SHUTDOWN INPUT
A logic-level signal will shut off the regulator output when a
“LOW” (
<
1.2V) is applied to the Shutdown input.
To prevent possible mis-operation, the Shutdown input must
be
actively
terminated.
If
open-collector logic, a pull-up resistor (20 k
to 100 k
rec-
ommended) should be connected from the Shutdown input
to the regulator input.
If the Shutdown input is driven from a source that actively
pulls high and low (like an op-amp), the pull-up resistor is not
required, but may be used.
If the shutdown function is not to be used, the cost of the
pull-up resistor can be saved by simply tying the Shutdown
input directly to the regulator input.
IMPORTANT:
Since the Absolute Maximum Ratings state
that the Shutdown input can not go more than 0.3V below
ground, the reverse-battery protection feature which protects
the regulator input is sacrificed if the Shutdown input is tied
directly to the regulator input.
If reverse-battery protection is required in an application, the
pull-up resistor between the Shutdown input and the regula-
tor input must be used.
the
input
is
driven
from
Typical Applications
DS011128-37
* In shutdown mode, ERROR will go high if it has been pulled up to an
*
* Exact value depends on dropout voltage. (See Application Hints)
FIGURE 3. ERROR Output Timing
Typical Application Circuit
DS011128-1
5V Regulator
DS011128-6
www.national.com
9
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LP2954IT | 5V and Adjustable Micropower Low-Dropout Voltage Regulators |
| LP2954AIS | 5V and Adjustable Micropower Low-Dropout Voltage Regulators |
| LP2954IS | 5V and Adjustable Micropower Low-Dropout Voltage Regulators |
| LP2956AMJ-QML | Dual Micropower Low-Dropout Voltage Regulators |
| LP2956AIM | Dual Micropower Low-Dropout Voltage Regulators |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP2954IM/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: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP2954IM/NOPB | 制造商:Texas Instruments 功能描述:Voltage Regulator IC |
| LP2954IMX | 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: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP2954IMX/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: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP2954IS | 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: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。