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参数资料
| 型号： | MAX1545ETL+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 33/43页 |
| 文件大小： | 0K |
| 描述： | IC QUICK-PWM DUAL-PHASE 40-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| 系列： | Quick-PWM™ |
| 应用： | 控制器，Intel Pentium? IV |
| 输入电压： | 2 V ~ 28 V |
| 输出数： | 1 |
| 输出电压： | 0.6 V ~ 1.85 V |
| 工作温度： | -40°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 40-WFQFN 裸露焊盘 |
| 供应商设备封装： | 40-TQFN-EP（6x6） |
| 包装： | 管件 |
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Dual-Phase, Quick-PWM Controllers for
Programmable CPU Core Power Supplies
phase, the peak inductor currents of each phase are
staggered, resulting in lower output ripple voltage by
reducing the total inductor ripple current. For 3- or 4-
phase operation, the maximum ESR to meet ripple
requirements is:
For a standard 300kHz application, the ESR zero frequen-
cy must be well below 95kHz, preferably below 50kHz.
Tantalum, Sanyo POSCAP, and Panasonic SP capacitors
in widespread use at the time of publication have typical
ESR zero frequencies below 50kHz. For example, the
R ESR ≤
( 2 V IN ? η TOTAL V OUT ) t ON ? η TOTAL V OUT t TRIG
V RIPPLE L
ESR needed to support a 30mV P-P ripple in a 40A design
is 30mV/(40A × 0.3) = 2.5m Ω . Four 330μF/2.5V Panasonic
SP (type XR) capacitors in parallel provide 2.5m Ω (max)
ESR. Their typical combined ESR results in a zero at
40kHz.
where η TOTAL is the total number of active phases, t ON
is the calculated on-time per phase, and t TRIG is the
trigger delay between the master’s DH rising edge and
the slave’s DH rising edge. The trigger delay must be
less than 1/(f SW × η TOTAL ) for stable operation. The
actual capacitance value required relates to the physi-
cal size needed to achieve low ESR, as well as to the
chemistry of the capacitor technology. Thus, the
capacitor is usually selected by ESR and voltage rating
rather than by capacitance value (this is true of polymer
types).
When using low-capacity ceramic filter capacitors,
capacitor size is usually determined by the capacity
needed to prevent V SAG and V SOAR from causing
problems during load transients. Generally, once
enough capacitance is added to meet the overshoot
requirement, undershoot at the rising load edge is no
longer a problem (see the V SAG and V SOAR equations
in the Transient Response section).
Output Capacitor Stability Considerations
For Quick-PWM controllers, stability is determined by
the value of the ESR zero relative to the switching fre-
quency. The boundary of instability is given by the fol-
lowing equation:
Ceramic capacitors have a high ESR zero frequency,
but applications with significant voltage positioning can
take advantage of their size and low ESR. Do not put
high-value ceramic capacitors directly across the out-
put without verifying that the circuit contains enough
voltage positioning and series PC board resistance to
ensure stability. When only using ceramic output
capacitors, output overshoot (V SOAR ) typically deter-
mines the minimum output capacitance requirement.
Their relatively low capacitance value can cause output
overshoot when stepping from full-load to no-load con-
ditions, unless a small inductor value is used (high
switching frequency) to minimize the energy transferred
from inductor to capacitor during load-step recovery.
The efficiency penalty for operating at 550kHz is about
5% when compared to the 300kHz circuit, primarily due
to the high-side MOSFET switching losses.
Unstable operation manifests itself in two related but
distinctly different ways: double-pulsing and feedback
loop instability. Double-pulsing occurs due to noise on
the output or because the ESR is so low that there is
not enough voltage ramp in the output voltage signal.
This “fools” the error comparator into triggering a new
cycle immediately after the minimum off-time period
has expired. Double-pulsing is more annoying than
where:
f ESR ≤
f SW
π
harmful, resulting in nothing worse than increased out-
put ripple. However, it can indicate the possible pres-
ence of loop instability due to insufficient ESR. Loop
instability can result in oscillations at the output after
line or load steps. Such perturbations are usually
f ESR =
1
2 π R EFF C OUT
damped, but can cause the output voltage to rise
above or fall below the tolerance limits.
The easiest method for checking stability is to apply a
and:
R EFF = R ESR + A VPS R SENSE + R PCB
where C OUT is the total output capacitance, R ESR is the
total equivalent-series resistance, R SENSE is the cur-
rent-sense resistance, A VPS is the voltage-positioning
gain, and R PCB is the parasitic board resistance
between the output capacitors and sense resistors.
very fast zero-to-max load transient and carefully
observe the output voltage ripple envelope for over-
shoot and ringing. It can help to simultaneously monitor
the inductor current with an AC current probe. Do not
allow more than one cycle of ringing after the initial
step-response under/overshoot.
______________________________________________________________________________________
33
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1545ETL+ | 功能描述:电压模式 PWM 控制器 Dual-Phase Quick-PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1545ETL+T | 功能描述:电压模式 PWM 控制器 Dual-Phase Quick-PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1545ETL-T | 功能描述:电压模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1546AETL | 制造商:Maxim Integrated Products 功能描述:DUAL-PHASE, QUICK-PWM CONTROLLER FOR IMVP CPU - Rail/Tube |
| MAX1546AETL+ | 制造商:Maxim Integrated Products 功能描述:DUAL-PHASE, QUICK-PWM CONTROLLER FOR IMVP CPU - Rail/Tube |
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