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参数资料
| 型号： | ISL6341IRZ-T |
| 厂商： | Intersil |
| 文件页数： | 15/17页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 10-TDFN |
| 标准包装： | 6,000 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 330kHz |
| 占空比： | 85% |
| 电源电压： | 4.5 V ~ 14.4 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
ISL6341, ISL6341A, ISL6341B, ISL6341C
frequency. When designing compensation networks, select
target crossover frequencies in the range of 10% to 30% of
the switching frequency, f SW .
This is just one method to calculate compensation components;
there are variations of the compensation break frequency
equations. The error amp is similar to that on other Intersil
Output Inductor Selection
The output inductor is selected to meet the output voltage
ripple requirements and minimize the converter ’s response
time to the load transient. The inductor value determines the
converter ’s ripple current and the ripple voltage is a function
of the ripple current. The ripple voltage and current are
Δ I =
V IN
regulators, so existing tools can be used here as well. Special
consideration is needed if the size of a ceramic output
capacitance in parallel with bulk capacitors gets too large; the
approximated by Equation 10:
V IN - V OUT V OUT
x
Fsw x L
Δ V OUT = Δ I x ESR
(EQ. 10)
calculation needs to model them both separately (attempting to
combine two different capacitors types into one composite
component model may not work properly; a special tool may be
needed; contact your local Intersil person for assistance).
Component Selection Guidelines
Output Capacitor Selection
An output capacitor is required to filter the output and supply
the load transient current. The filtering requirements are a
function of the switching frequency and the ripple current.
The load transient requirements are a function of the slew
rate (di/dt) and the magnitude of the transient load current.
These requirements are generally met with a mix of
capacitors and careful layout.
Modern components and loads are capable of producing
transient load rates above 1A/ns. High frequency capacitors
initially supply the transient and slow the current load rate
seen by the bulk capacitors. The bulk filter capacitor values
Increasing the value of inductance reduces the ripple current
and voltage. However, the large inductance values reduce
the converter ’s response time to a load transient.
One of the parameters limiting the converter ’s response to
a load transient is the time required to change the inductor
current. Given a sufficiently fast control loop design, the
ISL6341x will provide either 0% or 100% duty cycle in
response to a load transient. The response time is the time
required to slew the inductor current from an initial current
value to the transient current level. During this interval, the
difference between the inductor current and the transient
current level must be supplied by the output capacitor.
Minimizing the response time can minimize the output
capacitance required.
The response time to a transient is different for the
application of load and the removal of load. Equation 11
gives the approximate response time interval for application
and removal of a transient load:
are generally determined by the ESR (Effective Series
Resistance) and voltage rating requirements rather than
t RISE =
L x I TRAN
V IN - V OUT
t FALL =
L x I TRAN
V OUT
(EQ. 11)
actual capacitance requirements.
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 on
specific decoupling requirements.
Use only specialized low-ESR capacitors intended for
switching-regulator applications for the bulk capacitors. The
bulk capacitor’s ESR will determine the output ripple voltage
and the initial voltage drop after a high slew-rate transient. An
aluminum electrolytic capacitor’s ESR value is related to the
case size with lower ESR available in larger case sizes.
However, the Equivalent Series Inductance (ESL) of these
capacitors increases with case size and can reduce the
usefulness of the capacitor to high slew-rate transient loading.
Unfortunately, ESL is not a specified parameter. Work with
your capacitor supplier and measure the capacitor’s
impedance with frequency to select a suitable component. In
most cases, multiple electrolytic capacitors of small case size
perform better than a single large case capacitor.
15
where: I TRAN is the transient load current step, t RISE is the
response time to the application of load, and t FALL is the
response time to the removal of load. The worst case
response time can be either at the application or removal of
load. Be sure to check Equation 11 at the minimum and
maximum output levels for the worst case response time.
Input Capacitor Selection
Use a mix of input bypass capacitors to control the voltage
overshoot across the MOSFETs. Use small ceramic
capacitors for high frequency decoupling and bulk capacitors
to supply the current needed each time Q 1 turns on. Place the
small ceramic capacitors physically close to the MOSFETs
and between the drain of Q 1 and the source of Q 2 .
The important parameters for the bulk input capacitor are the
voltage rating and the RMS current rating. For reliable
operation, select the bulk capacitor with voltage and current
ratings above the maximum input voltage and largest RMS
current required by the circuit. The capacitor voltage rating
should be at least 1.25x greater than the maximum input
voltage and a voltage rating of 1.5x is a conservative
guideline. The RMS current rating requirement for the input
capacitor of a buck regulator is approximately 1/2 the DC
load current.
FN6538.2
December 2, 2008
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6353CRTZ | 功能描述:电流型 PWM 控制器 VR12 MEMORY CNTRLR 3 PHS 2 INT 5V DRVRS RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL6353CRTZ-T | 功能描述:电流型 PWM 控制器 VR12 MEMORY CNTRLR 3 PHS 2 INT 5V DRVRS RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL6353CRTZ-TS2568 | 制造商:Intersil Corporation 功能描述:INTEL, ISL6353CRTZ-T W/BARCODE LABELS, 12 MONTH D/C RESTRICT - Tape and Reel |
| ISL6353CRZ | 制造商:Intersil 功能描述:Multiphase PWM Regulator for VR12 DDR Memory Systems |
| ISL6353IRTZ | 功能描述:电流型 PWM 控制器 VR12 MEMORY CNTRLR 3 PHS 2 INT 5V DRVRS RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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