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| 型号： | MAX1544ETL+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 32/42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，AMD Hammer |
| 输入电压： | 2 V ~ 28 V |
| 输出数： | 1 |
| 输出电压： | 0.68 V ~ 1.55 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 Controller for
AMD Hammer CPU Core Power Supplies
Transient Response
The inductor ripple current impacts transient-response
performance, especially at low V IN - V OUT differentials.
Low inductor values allow the inductor current to slew
faster, replenishing charge removed from the output
filter capacitors by a sudden load step. The amount of
output sag is also a function of the maximum duty fac-
tor, which can be calculated from the on-time and mini-
mum off-time. For a dual-phase controller, the
worst-case output sag voltage can be determined by:
Output Capacitor Selection
The output filter capacitor must have low enough effec-
tive series resistance (ESR) to meet output ripple and
load-transient requirements, yet have high enough ESR
to satisfy stability requirements.
In CPU V CORE converters and other applications where
the output is subject to large-load transients, the output
capacitor ’ s size typically depends on how much ESR is
needed to prevent the output from dipping too low
under a load transient. Ignoring the sag due to finite
L ( ? I LOAD ( MAX ) ) 2 ? ? OUT ? + t OFF ( MIN ) ?
? ? ?
? ?
? ? 2 t OFF ( MIN ) ?
2 C OUT V OUT ? ?
? ?
? ?
? I LOAD ( MAX ) ? ? V OUT K ? ?
? ?
V IN ?
?
R ESR ≤
V SAG =
+ ? ? ? + t OFF ( MIN ) ?
2 C OUT
? ? V K ? ?
V IN ?
? ? ( V IN ? 2 V OUT ) K ? ?
? V IN ?
capacitance:
V STEP
? I LOAD ( MAX )
In non-CPU applications, the output capacitor ’ s size
often depends on how much ESR is needed to maintain
an acceptable level of output ripple voltage. The output
ripple voltage of a step-down controller equals the total
where t OFF(MIN) is the minimum off-time (see the
Electrical Characteristics ) and K is from Table 6.
The amount of overshoot due to stored inductor energy
can be calculated as:
inductor ripple current multiplied by the output capaci-
tor ’ s ESR. When operating multiphase systems out-of-
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
V SOAR ≈
( ? I LOAD ( MAX ) ) 2 L
2 η TOTAL C OUT V OUT
4-phase operation, the maximum ESR to meet ripple
requirements is:
where η TOTAL is the total number of active phases.
Setting the Current Limit
The minimum current-limit threshold must be high
R ESR ≤
V RIPPLE L
( 2 V IN ? η TOTAL V OUT ) t ON ? η TOTAL V OUT t TRIG
I LIMIT ( LOW ) > ? LOAD ( MAX ) ? ? 1 ?
η TOTAL ? ?
2 ?
enough to support the maximum load current when the
current limit is at the minimum tolerance value. The val-
ley of the inductor current occurs at I LOAD(MAX) minus
half the ripple current; therefore:
? I ? ? LIR ?
?
?
where η TOTAL is the total number of active phases, and
I LIMIT(LOW) equals the minimum current-limit threshold
voltage divided by the current-sense resistor (R SENSE ).
For the 30mV default setting, the minimum current-limit
threshold is 28mV.
Connect ILIM to V CC for the default current-limit thresh-
old (see the Electrical Characteristics ). In adjustable
mode, the current-limit threshold is precisely 1/20 the
voltage seen at ILIM. For an adjustable threshold, con-
nect a resistive divider from REF to GND with ILIM con-
nected to the center tap. When adjusting the current
limit, use 1% tolerance resistors with approximately
10μA of divider current to prevent a significant increase
of errors in the current-limit tolerance.
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 x 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).
32
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1544ETL+ | 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 |
| MAX1544ETL+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 |
| MAX1544ETL+TG075 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1544ETL-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 |
| MAX1544EVKIT | 制造商:Maxim Integrated Products 功能描述:DUAL-PHASE, QUICK-PWM CONTROLLER FOR AMD HAMM - Bulk |
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