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參數資料
| 型號： | LMS5214IMG-2.6 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | 80mA, Low Dropout Voltage Regulator with Auto Discharge Function in SC70 |
| 中文描述： | 2.6 V FIXED POSITIVE LDO REGULATOR, 0.5 V DROPOUT, PDSO5 |
| 封裝： | SC-70, 5 PIN |
| 文件頁數： | 8/10頁 |
| 文件大?。?/td> | 286K |
| 代理商： | LMS5214IMG-2.6 |
Typical Characteristics
Unless otherwise specified, T
A
= 25C, V
OUT
= 2.8V, C
L
= 0.47μF (Continued)
Start Up Characteristics
20043104
Application Information
The LMS5214 is a low dropout, linear regulator designed
primarily for battery-powered applications. The LMS5214
can be used with low cost ceramic capacitors, typical value
of 470nF.
The LMS5214 is an enhanced version of the LMS5213 with
auto discharge function which actively discharges the output
voltage to ground when the device is placed in shutdown
mode
As illustrated in the simplified schematics, the LMS5214
consists of a 1.25V reference, error amplifier, P-channel
pass transistor and internal feedback voltage divider. The
1.25V reference is connected to the input of the error amp.
The error amp compares this reference with the feedback
voltage. If the feedback voltage is lower than the reference,
the pass transistor gate is pulled lower allowing more current
to pass and increasing the output voltage. If the feedback
voltage is too high, the pass transistor gate is pulled up
allowing less current to pass to the output. The output volt-
age is fedback through the resistor divider. Additional blocks
include short circuit current protection and thermal protec-
tion.
The LMS5214 features an 80mA P-channel MOSFET tran-
sistor. This provides several advantages over similar designs
using PNP pass transistors including longer battery life.
The P-channel MOSFET requires no base drive, which re-
duces quiescent current considerably. PNP based regulators
waste considerable amounts of current in dropout when the
pass transistor saturates. They also have high base drive
currents under large loads. The LMS5214 does not suffer
from these problems and consumes only the specified qui-
escent current under light and heavy loads.
External Capacitors
Like any low-dropout regulators, the LMS5214 requires ex-
ternal capacitors for regulator stability. The LMS5214 is spe-
cially designed for portable applications requiring minimum
board space and the smallest components.
A 1μF capacitor should be placed from V
to GND if there is
more than 10 inches of wire between the input and AC filter
or when a battery is used as the input. This capacitor must
be located a distance of not more than 1cm from the input
pin and returned to a clean analog ground.
The LMS5214 is designed to work with high quality tantalum
capacitors and small ceramic output capacitors. Ceramic
capacitors ranging between 470nF to 4.7μF are the smallest
and least expensive.
No-Load Stability
The LMS5214 will remain stable and in regulation with
no-load (other than the internal voltage divider). This is
especially important in CMOS RAM keep-alive applications.
Enable Input
The LMS5214 is shut off by pulling the V
pin below 0.6V;
all internal circuitry is powered off and the quiescent current
is typically 10nA. Pulling the V
high above 2V re-enables
the device and allows operation. If the shut down feature is
not used, the V
pin should be tied to V
IN
to keep the
regulator output on all the time.
Thermal Behavior
The LMS5214 regulator has internal thermal shutdown to
protect the device from over heating. Under all operating
conditions, the maximum junction temperature of the
LMS5214 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 dissipa-
tion is
P
D(MAX)
= (T
J(MAX)
- T
A
)/
θ
JA
θ
is the junction-to-ambient thermal resistance, 478C/W
for the LMS5214 in the SC70 package. T
is the maximum
ambient temperature T
is the maximum junction tem-
perature of the die, 125C
When operating the LMS5214 at room temperature, the
maximum power dissipation is 209mW.
The actual power dissipated by the regulator is
P
D
= (V
IN
-V
OUT
) I
L
+ V
IN
I
GND
The figure below shows the voltage and currents, which are
present in the circuit.
L
www.national.com
8
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相關代理商/技術參數 |
參數描述 |
|---|---|
| LMS5214IMG-3.0 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:80mA, Low Dropout Voltage Regulator with Auto Discharge Function in SC70 |
| LMS5214IMG-3.0 | 制造商:Texas Instruments 功能描述:V REG LDO 80MA 3.0V 5214 SC-70-5 |
| LMS5214IMG-3.3 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述: |
| LMS5214IMG-3.3 | 制造商:Texas Instruments 功能描述:V REG LDO 80MA 3.3V 5214 SC-70-5 |
| LMS5214IMG-3.3/NOPB | 功能描述:IC REG LDO 3.3V 80MA SC70-5 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 穩(wěn)壓器拓撲結構:正，固定式 輸出電壓:3.1V 輸入電壓:最高 5.5V 電壓 - 壓降（標準）:- 穩(wěn)壓器數量:1 電流 - 輸出:300mA 電流 - 限制（最?。?420mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-5 細型，TSOT-23-5 供應商設備封裝:TSOT-23-5 包裝:帶卷 (TR) |
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