参数资料
| 型号： | ISL6443AIVZ |
| 厂商： | Intersil |
| 文件页数： | 16/19页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR SGL/STP DWN PWM 28TSSOP |
| 产品培训模块： | Solutions for Industrial Control Applications |
| 标准包装： | 50 |
| 应用： | 电源 |
| 电流 - 电源： | 2mA |
| 电源电压： | 5.6 V ~ 24 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-TSSOP（0.173"，4.40mm 宽） |
| 供应商设备封装： | 28-TSSOP |
| 包装： | 管件 |
ISL6443A
calculating the temperature rise according to package
thermal-resistance specifications.
Output Capacitor Selection
The output capacitors for each output have unique
requirements. In general, the output capacitors should be
selected to meet the dynamic regulation requirements
including ripple voltage and load transients. Selection of
output capacitors is also dependent on the output inductor,
so some inductor analysis is required to select the output
capacitors.
Use only specialized low-ESR capacitors intended for
switching-regulator applications at 300kHz for the bulk
capacitors. In most cases, multiple small-case electrolytic
capacitors perform better than a single large-case capacitor.
The stability requirement on the selection of the output
capacitor is that the ‘ESR zero’ (f Z ) be between 1.2kHz and
30kHz. This range is set by an internal, single compensation
zero at 6kHz. The ESR zero can be a factor of five on either
side of the internal zero and still contribute to increased
phase margin of the control loop. Therefore,
C OUT = -------------------------------------
One of the parameters limiting the converter ’s response to a
load transient is the time required for the inductor current to
1
2 Π ( ESR ) ( f Z )
(EQ.14)
slew to it’s new level. The ISL6443A will provide either 0% or
93% duty cycle in response to a load transient.
The response time is the time interval required to slew the
inductor current from an initial current value to the load
current level. During this interval the difference between the
inductor current and the transient current level must be
supplied by the output capacitor(s). Minimizing the response
time can minimize the output capacitance required. Also, if
the load transient rise time is slower than the inductor
response time, as in a hard drive or CD drive, it reduces the
requirement on the output capacitor.
The maximum capacitor value required to provide the full,
rising step, transient load current during the response time of
the inductor is:
In conclusion, the output capacitors must meet three criteria:
1. They must have sufficient bulk capacitance to sustain the
output voltage during a load transient while the output
inductor current is slewing to the value of the load
transient.
2. The ESR must be sufficiently low to meet the desired
output voltage ripple due to the output inductor current.
3. The ESR zero should be placed, in a rather large range,
to provide additional phase margin.
The recommended output capacitor value for the ISL6443A
is between 150μF to 680μF, to meet stability criteria with
external compensation. Use of aluminum electrolytic,
POSCAP, or tantalum type capacitors is recommended. Use
of low ESR ceramic capacitors is possible but would take
( L O ) ( I TRAN )
2 ( V IN – V O ) ( DV OUT )
2
C OUT = -----------------------------------------------------------
(EQ.12)
more rigorous loop analysis to ensure stability.
Output Inductor Selection
where, C OUT is the output capacitor(s) required, L O is the
output inductor, I TRAN is the transient load current step, V IN
is the input voltage, V O is output voltage, and DV OUT is the
drop in output voltage allowed during the load transient.
High frequency capacitors initially supply the transient
current and slow the load rate-of-change seen by the bulk
capacitors. The bulk filter capacitor values are generally
The PWM converters require output inductors. The output
inductor is selected to meet the output voltage ripple
requirements. The inductor value determines the converter ’s
ripple current and the ripple voltage is a function of the ripple
current and output capacitor(s) ESR. The ripple voltage
Equation 15:
( V IN – V OUT ) ( V OUT )
( f S ) ( L ) ( V IN )
determined by the ESR (Equivalent Series Resistance) and
voltage rating requirements as well as actual capacitance
requirements.
Δ I L = ----------------------------------------------------------
(EQ.15)
The output voltage ripple is due to the inductor ripple current
and the ESR of the output capacitors as defined by
Equation 13:
V RIPPLE = Δ I L ( ESR ) (EQ.13)
High frequency decoupling capacitors should be placed as
close to the power pins of the load as physically possible. Be
careful not to add inductance in the circuit board wiring that
could cancel the usefulness of these low inductance
components. Consult with the manufacturer of the load
circuitry for specific decoupling requirements.
16
For the ISL6443A, inductor values between 6.4μH to 10μH
are recommended when using the “Typical Application
thorough stability study should be done.
FN6600.2
June 2, 2008
相关PDF资料 |
PDF描述 |
|---|---|
| ISL6443IR-TK | IC CTRLR PWM DUAL 300KHZ 28-QFN |
| ISL6444CA-T | IC CONTROLLER DDR 28-QSOP |
| ISL6445IAZ | IC REG CTRLR BUCK PWM CM 24-QSOP |
| ISL6455AIRZS2698 | IC REG TRPL SYNC DUAL LDO 24-QFN |
| ISL6504CR-T | IC MULTIPLE POWER CTRLR 20-QFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6443AIVZ-TK | 功能描述:IC CTRLR SGL/STP DWN PWM 28TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
| ISL6443IR | 功能描述:IC CTRLR SGL/STEP DOWN PWM 28QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
| ISL6443IR-T | 功能描述:IC CTRLR PWM DUAL 300KHZ 28-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
| ISL6443IR-TK | 功能描述:IC CTRLR PWM DUAL 300KHZ 28-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
| ISL6443IRZ | 功能描述:IC CTRLR SGL/STEP DOWN PWM 28QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
发布紧急采购，3分钟左右您将得到回复。