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参数资料
| 型号： | LM3420A16.8MDA |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, UUC |
| 封装： | DIE |
| 文件页数： | 2/21页 |
| 文件大小： | 468K |
| 代理商： | LM3420A16.8MDA |
Five Lead Surface Mount Package Information
The small SOT23-5 package allows only 4 alphanumeric characters to identify the product. The table below contains the field in-
formation marked on the package.
The first letter “D” identifies the part as a Driver, the next two numbers indicate the voltage, “02” for a 4.2V part, “07” for an 8.2V
part, “03” for an 8.4V part, “04” for a 12.6V part, and “05” for a 16.8V part. The fourth letter indicates the grade, “B” for standard
grade, “A” for the prime grade.
The SOT23-5 surface mount package is only available on tape in quantity increments of 1000 on tape and reel (indicated by the
letters “M5” in the part number), or in quantity increments of 3000 on tape and reel (indicated by the letters “M5X” in the part num-
ber).
Product Description
The LM3420 is a shunt regulator specifically designed to be
the reference and control section in an overall feedback loop
of a Lithium-Ion battery charger. The regulated output volt-
age is sensed between the IN pin and GROUND pin of the
LM3420. If the voltage at the IN pin is less than the LM3420
regulating voltage (V
REG), the OUT pin sources no current.
As the voltage at the IN pin approaches the V
REG voltage,
the OUT pin begins sourcing current. This current is then
used to drive a feedback device (opto-coupler), or a power
device (linear regulator, switching regulator, etc.), which ser-
vos the output voltage to be the same value as V
REG.
In some applications, (even under normal operating condi-
tions) the voltage on the IN pin can be forced above the
V
REG voltage. In these instances, the maximum voltage ap-
plied to the IN pin should not exceed 20V. In addition, an ex-
ternal resistor may be required on the OUT pin to limit the
maximum current to 20 mA.
Compensation
The inverting input of the error amplifier is brought out to al-
low overall closed-loop compensation. In many of the appli-
cations circuits shown here, compensation is provided by a
single capacitor (C
C) connected from the compensation pin
to the out pin of the LM3420. The capacitor values shown in
the schematics are adequate under most conditions, but
they can be increased or decreased depending on the de-
sired loop response. Applying a load pulse to the output of a
regulator circuit and observing the resultant output voltage
response is an easy method of determining the stability of
the control loop.
Analyzing more complex feedback loops requires additional
information.
The formula for AC gain at a frequency (f) is as follows;
where R
f ≈ 75 k for the 4.2V part, Rf ≈ 181 k for the 8.4V
part, R
f ≈ 287 k for the 12.6V part, and Rf ≈ 392 k for the
16.8V part.
The resistor (R
f) in the formula is an internal resistor located
on the die. Since this resistor value will affect the phase mar-
gin, the worst case maximum and minimum values are im-
Voltage
Grade
Order
Package
Supplied as
Information
Marking
4.2V
A (Prime)
LM3420AM5-4.2
D02A
1000 unit increments on tape and reel
4.2V
A (Prime)
LM3420AM5X-4.2
D02A
3000 unit increments on tape and reel
4.2V
B (Standard)
LM3420M5-4.2
D02B
1000 unit increments on tape and reel
4.2V
B (Standard)
LM3420M5X-4.2
D02B
3000 unit increments on tape and reel
8.2V
A (Prime)
LM3420AM5-8.2
D07A
1000 unit increments on tape and reel
8.2V
A (Prime)
LM3420AM5X-8.2
D07A
3000 unit increments on tape and reel
8.2V
B (Standard)
LM3420M5-8.2
D07B
1000 unit increments on tape and reel
8.2V
B (Standard)
LM3420M5X-8.2
D07B
3000 unit increments on tape and reel
8.4V
A (Prime)
LM3420AM5-8.4
D03A
1000 unit increments on tape and reel
8.4V
A (Prime)
LM3420AM5X-8.4
D03A
3000 unit increments on tape and reel
8.4V
B (Standard)
LM3420M5-8.4
D03B
1000 unit increments on tape and reel
8.4V
B (Standard)
LM3420M5X-8.4
D03B
3000 unit increments on tape and reel
12.6V
A (Prime)
LM3420AM5-12.6
D04A
1000 unit increments on tape and reel
12.6V
A (Prime)
LM3420AM5X-12.6
D04A
3000 unit increments on tape and reel
12.6V
B (Standard)
LM3420M5-12.6
D04B
1000 unit increments on tape and reel
12.6V
B (Standard)
LM3420M5X-12.6
D04B
3000 unit increments on tape and reel
16.8V
A (Prime)
LM3420AM5-16.8
D05A
1000 unit increments on tape and reel
16.8V
A (Prime)
LM3420AM5X-16.8
D05A
3000 unit increments on tape and reel
16.8V
B (Standard)
LM3420M5-16.8
D05B
1000 unit increments on tape and reel
16.8V
B (Standard)
LM3420M5X-16.8
D05B
3000 unit increments on tape and reel
FIGURE 1. SOT23-5 Marking
LM3420-4.2/LM3420-8.2/LM3420-8.4/LM3420-12.6/LM3420-16.8
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相关PDF资料 |
PDF描述 |
|---|---|
| LM3420M5-12.6/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3420AM5-12.6/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3420M5X-16.8/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3420AM5-4.2/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3420M5-8.4/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM3420AL-4.2 DIE | 制造商:Texas Instruments 功能描述: |
| LM3420AL-8.2 WAF | 制造商:Texas Instruments 功能描述: |
| LM3420AM5-12.6 | 功能描述:IC CTRLR LIION BAT CHRG SOT23-5 RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:1 系列:- 功能:充电管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:3.75 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:剪切带 (CT) 产品目录页面:669 (CN2011-ZH PDF) 其它名称:MCP73831T-2ACI/OTCT |
| LM3420AM5-12.6/NOPB | 制造商:Texas Instruments 功能描述:Battery Charger Li-Ion 15mA 12.6V 5-Pin SOT-23 T/R |
| LM3420AM5-16.8 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Lithium-Ion Battery Charge Controller |
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