参数资料
| 型号： | SP6654EU-L |
| 厂商： | Exar Corporation |
| 文件页数： | 12/17页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 0.8A 10MSOP |
| 标准包装： | 50 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1 V ~ 5.5 V |
| 输入电压： | 2.7 V ~ 5.5 V |
| 电流 - 输出： | 800mA |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 管件 |
| 供应商设备封装： | 10-MSOP |
APPLICATION INFORMATION
current ripple of almost 300mA would produce
very stable regulation and fast load transient
response at the expense of slightly reduced
efficiency.
Other inductor parameters are important: the in-
ductor current rating and the DC resistance. When
the current through the inductor reaches the level
of I SAT , the inductance drops to 70% of the
nominal value. This non-linear change can cause
stability problems or excessive fluctuation in in-
ductor current ripple. To avoid this, the inductor
should be selected with saturation current at least
equal to the maximum output current of the con-
verter plus half the inductor current ripple. To
provide the best performance in dynamic condi-
tions such as start-up and load transients, inductors
should be chosen with saturation current close to
the SP6654 inductor current limit of 1.25A.
DC resistance, another important inductor charac-
teristic, directly affects the efficiency of the con-
verter, so inductors with minimum DC resistance
should be chosen for high efficiency designs.
Recommended inductors with low DC resistance
are listed in table 2. Preferred inductors for on
board power supplies with the SP6654 are mag-
netically shielded types to minimize radiated mag-
netic field emissions.
Capacitor Selection
The SP6654 has been designed to work with very
low ESR output capacitors (listed in Table 2
Component Selection) which for the typical appli-
cation circuit are 22 μ F ceramic, POSCAP or Alu-
minum Polymer. These capacitors combine small
size, low ESR and good value. To regulate the
output with low ESR capacitors of 0.01 ? or less,
an internal ramp voltage V RAMP has been added to
the FB signal to reliably trip the loop comparator
(as described in the Operations section).
Output ripple for a buck regulator is determined
mostly by output capacitor ESR, which for the
SP6654 with a constant inductor current ripple can
be expressed as:
V OUT (ripple) = I LR * R ESR
For the 22 μ F POSCAP with 0.04 ? ESR, and a
10 μ H inductor yielding 200mA inductor current
ripple I LR , the V OUT ripple would be 8mVpp.
Since 8mV is a very small signal level, the actual
value would probably be larger due to noise and
layout issues, but this illustrates that the SP6654
output ripple can be very low indeed. To improve
stability, a small ceramic capacitor, C F = 22pF
should be paralleled with the feedback voltage
divider RF, as shown on the typical application
schematic on page 1. Another function of the
output capacitance is to hold up the output voltage
during the load transients and prevent excessive
overshoot and undershoot. The typical perfor-
mance characteristics curves show very good load
step transient response for the SP6654 with the
recommended output capacitance of 22 μ F ce-
ramic.
The input capacitor will reduce the peak current
drawn from the battery, improve efficiency and
significantly reduce high frequency noises in-
duced by a switching power supply. The typical
input capacitor for the SP6654 is 22 μ F ceramic,
POSCAP or Aluminum Polymer. These capaci-
tors will provide good high frequency bypassing
and their low ESR will reduce resistive losses for
higher efficiency. An RC filter is recommended
for the V IN pin 2 to effectively reduce the noise for
the ICs analog supply rail which powers sensitive
circuits. This time constant needs to be at least 5
times greater than the switching period, which is
calculated as 1/FLP during the CCM mode. The
typical application schematic uses the values of
R VIN = 10 ? and C VIN = 1 μ F to meet these require-
ments.
Date: 2/1/05
SP6654 High Efficiency 800mA Synchronous Buck Regulator
12
? Copyright 2005 Sipex Corporation
相关PDF资料 |
PDF描述 |
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| SP6655ER-L/TR | IC REG BUCK SYNC ADJ 0.4A 10DFN |
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| SP6661EU-L/TR | IC REG SWITCHD CAP DBL INV 8MSOP |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP6654EU-L/TR | 功能描述:DC/DC 开关控制器 High Eff 800mA Synchronous RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| SP6655 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Efficiency 400mA Synchronous Buck Regulator Ideal for portable designs powered with Li Ion battery |
| SP6655EB | 功能描述:电源管理IC开发工具 Eval Board for SP6655 Series RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| SP6655ER | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP6655ER/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Efficiency 400mA Synchronous Buck Regulator Ideal for portable designs powered with Li Ion battery |
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