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参数资料
| 型号： | MAX1937EEI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 19/24页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM HYBRID 28-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 混合物 |
| 输出数： | 1 |
| 频率 - 最大： | 500kHz |
| 占空比： | 50% |
| 电源电压： | 6 V ~ 24 V |
| 降压： | 无 |
| 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： | 0°C ~ 85°C |
| 封装/外壳： | 28-QSOP |
| 包装： | 带卷 (TR) |
Two-Phase Desktop CPU Core Supply
Controllers with Controlled VID Change
(V SAG ) is no longer a problem. The amount of overshoot
from stored inductor energy can be calculated as:
tems that may be powered from very low impedance
sources.
V SOAR =
I 2 PEAK × L
2 × C OUT × V OUT
Multiple smaller value capacitors can be used in paral-
lel to satisfy the ESR and capacitance requirements.
Selecting a BST Capacitor
where I PEAK is the peak inductor current.
The undershoot at the rising load edge of a load tran-
sient is calculated from:
The BST capacitors must be large enough to handle
the gate-charging requirements of the high-side
MOSFETs. For most applications, 0.22μF ceramic
capacitors are recommended.
L × Δ I 2 LOAD × ? OUT
+ t OFF ( MIN ) ?
2 × C OUT × V OUT × ?
? ( V IN ? V OUT ) × K
V SAG =
? V × K ?
? V IN ?
? V IN
? t OFF ( MIN )
BST capacitors are needed to keep the voltage on the
BST_ pins from dropping too much when the high-side
MOSFET gates are charged. A capacitor value that
prevents V BST _ from dropping more than 100mV to
200mV is adequate. The capacitance needed for the
BST_ capacitor is calculated from:
where Δ I LOAD is the change in load current, and K is
4μs.
C BST _ =
Q GH
Δ V BST _
To ensure stability, make sure that the zero frequency
created by the output capacitance, and the ESR of the
output capacitor do not exceed 50kHz. The zero fre-
quency is found from:
where Q GH is the total gate charge of the high-side
MOSFET and Δ V BST_ is the amount that the voltage on
the BST_ pin drops when the gate is charged. If using
multiple MOSFETs in parallel, use the sum of all the
f zESR =
1
2 π × ESR COUT × C OUT
gate charges for Q GH .
Setting the Current Limit
Current limit sets the maximum value of the inductor
Currently, aluminum electrolytic, Sanyo POSCAP, and
Panasonic SP capacitors have ESR zero frequencies
“valley” current. I VALLEY is calculated from the following
equation:
× ? 1 ?
2 ?
well below 50kHz. When using ceramic capacitors, it
might be necessary to use a series resistance to
ensure that the ESR zero is below 50kHz.
I VALLEY =
I LOAD ( MAX )
2
?
?
LIR ?
?
Input Capacitor Selection
The input capacitor reduces peak currents drawn from
the power source and reduces noise and voltage ripple
on the input caused by the circuit’s switching. The input
capacitor must meet the ripple current requirement
(I RMS ) imposed by the switching currents as defined by
the following equation:
The current-limit threshold (I LIMIT ) must be set higher
than the valley current:
I LIMIT > I VALLEY
The current-limit threshold is set by the voltage at ILIM
and the value of the current-sense resistors:
I RMS = LOAD
I
2
V OUT × ( V IN ? V OUT )
V IN
I LIMIT =
V ILIM
10 × R CS
where V ILIM is the voltage on the ILIM pin (0.1V to 2V)
I RMS has a maximum value when the input voltage
equals twice the output voltage (V IN = 2V OUT ), so
I RMS(MAX) = I LOAD / 2. For most applications, nontanta-
lum capacitors (ceramic, aluminum electrolytic, poly-
mer, or OS-CON) are preferred at the input because of
their robustness with high inrush currents typical of sys-
and R CS is the value of the current-sense resistor. If the
on-resistance of the low-side MOSFET is used for cur-
rent sensing, then the maximum value of the on-resis-
tance (overtemperature and part-to-part variation) must
be used for R CS .
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1937EEI-TG069 | 制造商:Maxim Integrated Products 功能描述: |
| MAX1938EEI | 功能描述:DC/DC 开关控制器 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 |
| MAX1938EEI-T | 功能描述:DC/DC 开关控制器 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 |
| MAX1938EEI-TG069 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1938EVKIT | 功能描述:电源管理IC开发工具 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 |
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