參數(shù)資料
型號(hào): L5985TR
廠商: 意法半導(dǎo)體
英文描述: 2A step-down switching regulator
中文描述: 第2A降壓型開關(guān)穩(wěn)壓器
文件頁數(shù): 16/36頁
文件大?。?/td> 757K
代理商: L5985TR
L5985
Application informations
16/36
5.3
Output capacitor selection
The current in the capacitor has a triangular waveform (with zero average value) which
generates a voltage ripple across it. This ripple is due to the capacitive component and the
resistive component (ESR). So the output capacitor has to be selected in order to have a
voltage ripple compliant with the application requirements.
The amount of the voltage ripple can be calculated starting from the current ripple obtained
by the inductor selection.
Equation 9
Usually the resistive component of the ripple is much higher than the capacitive one, if the
output capacitor adopted is not a multi layer ceramic capacitor (MLCC) with very low ESR
value.
The output capacitor is important also for loop stability: it fixes the double LC filter pole and
the zero due to its ESR. In
Chapter 5.4
, it will be illustrated how to consider its effect in the
system stability.
For example with V
OUT
= 3.3V, V
IN
= 12V,
I
L
= 0.6A (resulting by the inductor value), in
order to have a
V
OUT
= 0.01·V
OUT
, if the multi layer capacitor are adopted, 10uF are
needed and the ESR effect on the output voltage ripple can be neglected. In case of not
negligible ESR (electrolytic or tantalum capacitors), the capacitor is chosen taking into
account its ESR value. So 100uF with ESR = 40m
is compliant with the requested output
voltage ripple
.
The output capacitor is also important to sustain the output voltage when a load transient
with high slew rate is required by the load. When the load transient slew rate exceeds the
system bandwidth the output capacitor provides the current to the load. So if the high slew
rate load transient is required by the application the output capacitor and system bandwidth
have to be chosen in order to sustain the load transient.
In the table below some capacitor series are listed.
Coiltronics
CD1
15 to 22
2.9 to 3.6
UP2.8B
4.7 to 10
2.7 to 3.9
BI
HM76-3
15 to 33
2.5 to 3.7
SUMIDA
CDRH8D28
4.7 to 10
2.5 to 3.4
CDRH8D28/HP
15 to 22
2.5 to 2.8
Table 6.
Inductors
Manufacturer
Series
Inductor Value (
μ
H)
Saturation Current (A)
V
OUT
ESR
I
MAX
I
8 C
OUT
f
SW
------------------------------------
+
=
相關(guān)PDF資料
PDF描述
L5991 PRIMARY CONTROLLER WITH STANDBY
L5991A PRIMARY CONTROLLER WITH STANDBY
L5991AD PRIMARY CONTROLLER WITH STANDBY
L5991D PRIMARY CONTROLLER WITH STANDBY
L5993 CONSTANT POWER CONTROLLER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L5986 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A buck switching regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5986A 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A STEP-DOWN SWITCH REG RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5986ATR 功能描述:直流/直流開關(guān)調(diào)節(jié)器 Step-down switch regulator, 2.5A RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5986TR 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A Step-down Switch Regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5987 功能描述:直流/直流開關(guān)調(diào)節(jié)器 3 A buck switching regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5