参数资料
| 型号： | LT3085EMS8E#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 10/28页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO ADJ .5A 8-MSOP |
| 产品培训模块： | LT3085 Adjustable Low Dropout Regulator More Information on LDOs |
| 标准包装： | 50 |
| 稳压器拓扑结构： | 正，可调式 |
| 输出电压： | 可调 |
| 输入电压： | 1.2 V ~ 36 V |
| 电压 - 压降（标准）： | 1.35V @ 500mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 500mA |
| 电流 - 限制（最小）： | 500mA |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽）裸露焊盘 |
| 供应商设备封装： | 8-MSOP-EP |
| 包装： | 管件 |
| 产品目录页面： | 1331 (CN2011-ZH PDF) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页当前第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页
LT3085
APPLICATIONS INFORMATION
Input Capacitance and Stability
The LT3085 is designed to be stable with a minimum
capacitance of 1μF at each input pin. Ceramic capacitors
with low ESR are available for use to bypass these pins,
but in cases where long wires connect the LT3085 inputs
to a power supply (and also from ground of the LT3085
circuitry back to power supply ground), this causes insta-
bilities. This happens due to the wire inductance forming
an LC tank circuit with the input capacitor and not as a
result of instability on the LT3085.
The self-inductance, or isolated inductance, of a wire is
directly proportional to its length. The diameter does not
have a major in?uence on its self-inductance. As an ex-
ample, the self-inductance of a 2-AWG isolated wire with a
diameter of 0.26in. is approximately half the self-inductance
of a 30-AWG wire with a diameter of 0.01in. One foot of
30-AWG wire has 465nH of self-inductance.
The overall self-inductance of a wire is reduced in one of
two ways. One is to divide the current ?owing towards
the LT3085 between two parallel conductors. In this
case, the farther apart the wires are from each other, the
more the self-inductance is reduced, up to a 50% reduc-
tion when placed a few inches apart. Splitting the wires
basically connects two equal inductors in parallel, but
placing them in close proximity gives the wires mutual
inductance adding to the self-inductance. The second
and most effective way to reduce overall inductance is to
place both forward- and return-current conductors (the
wire for the input and the wire for ground) in very close
proximity. Two 30-AWG wires separated by only 0.02in.
used as forward- and return-current conductors reduce
the overall self-inductance to approximately one-?fth that
of a single isolated wire.
If the LT3085 is powered by a battery mounted in close
proximity on the same circuit board, a 2.2μF input capaci-
tor is suf?cient for stability. When powering from distant
supplies, use a larger input capacitor based on a guide-
line of 1μF plus another 1μF per 8 inches of wire length.
As power supply impedance does vary, the amount of
capacitance needed to stabilize your application will also
vary. Extra capacitance placed directly on the output of
the power supply requires an order of magnitude more
capacitance as opposed to placing extra capacitance close
to the LT3085.
Using series resistance between the power supply and
the input of the LT3085 also stabilizes the application.
As little as 0.1Ω to 0.5Ω, often less, is all that is needed
to provide damping in the circuit. If the extra impedance
between the power supply and the input is unacceptable,
placing the resistors in series with the capacitors will pro-
vide damping to prevent the LC resonance from causing
full-blown oscillation.
Stability and Output Capacitance
The LT3085 requires an output capacitor for stability. It
is designed to be stable with most low ESR capacitors
(typically ceramic, tantalum or low ESR electrolytic). A
minimum output capacitor of 2.2μF with an ESR of 0.5Ω
or less is recommended to prevent oscillations. Larger
values of output capacitance decrease peak deviations
and provide improved transient response for larger load
current changes. Bypass capacitors, used to decouple
individual components powered by the LT3085, increase
the effective output capacitor value.
For improvement in transient performance, place a capaci-
tor across the voltage setting resistor. Capacitors up to
1μF can be used. This bypass capacitor reduces system
noise as well, but start-up time is proportional to the time
constant of the voltage setting resistor (R SET in Figure 1)
and SET pin bypass capacitor.
Extra consideration must be given to the use of ceramic
capacitors. Ceramic capacitors are manufactured with a
variety of dielectrics, each with different behavior across
temperature and applied voltage. The most common
dielectrics used are speci?ed with EIA temperature
characteristic codes of Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitances
3085fb
10
相关PDF资料 |
PDF描述 |
|---|---|
| LT1121IS8-5#PBF | IC REG LDO 5V .15A 8-SOIC |
| HMC17DRTI-S13 | CONN EDGECARD 34POS .100 EXTEND |
| RSC12DTES | CONN EDGECARD 24POS .100 EYELET |
| EMM28DTMS | CONN EDGECARD 56POS R/A .156 SLD |
| HSC22DRES-S13 | CONN EDGECARD 44POS .100 EXTEND |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3085EMS8E-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:Adjustable 500mA Single Resistor Low Dropout Regulator |
| LT3085EMS8E-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Adjustable 500mA Single Resistor Low Dropout Regulator |
| LT3085IDCB | 制造商:LINER 制造商全称:Linear Technology 功能描述:Adjustable 500mA Single Resistor Low Dropout Regulator |
| LT3085IDCB#PBF | 制造商:Linear Technology 功能描述:LDO Regulator Pos 0V to 36V 0.5A 6-Pin DFN EP 制造商:Linear Technology 功能描述:LDO Regulator Pos 0V to 36V 0.5A 6-Pin DFN EP Bulk |
| LT3085IDCB#TRMPBF | 功能描述:IC REG LDO ADJ .5A 6-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 标准包装:800 系列:- 稳压器拓扑结构:正，固定式 输出电压:2.5V 输入电压:最高 16V 电压 - 压降（标准）:0.7V @ 4A 稳压器数量:1 电流 - 输出:4A 电流 - 限制（最小）:4.2A 工作温度:0°C ~ 125°C 安装类型:表面贴装 封装/外壳:TO-263-6，D²Pak（5 引线+接片），TO-263BA 供应商设备封装:TO-263-5 包装:带卷 (TR) 其它名称:AP1184K525L-13AP1184K525LDITR |
发布紧急采购，3分钟左右您将得到回复。