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| 型号： | MAX8655ETN+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 15/23页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 25A 56TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.7 V ~ 5.5 V |
| 输入电压： | 4.5 V ~ 25 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 200kHz ~ 1MHz |
| 电流 - 输出： | 25A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 56-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 56-TQFN-EP（8x8） |
Highly Integrated, 25A, Wide-Input,
Internal MOSFET, Step-Down Regulator
R 4 = R 6 × ? OUT ? 1 ?
R FSYNC =
? 9 . 914
L =
120 × R L
f S × L
Setting the Output Overvoltage Protection
To set the overvoltage threshold voltage for the
MAX8655, connect OVP to the center of an external
resistor-divider connected between the output and GND
(R4 and R6 of Figure 3). Select R6 between 5k ? and
24k ? , then calculate R4 with the following equation:
? V ?
? V OVP ?
where V OVP = 1.15 x V FB .
Inductor Selection
There are several parameters that must be examined
when determining which inductor is to be used. Input
voltage, output voltage, load current, switching fre-
quency, and LIR. LIR is the ratio of the inductor current
ripple to the maximum DC load current. A higher LIR
value allows for a smaller inductor, but results in higher
losses and higher output ripple. A good compromise
between size and efficiency is an LIR of 0.3. Once all
the parameters are chosen, the inductor value is deter-
mined as follows:
V OUT × ( V IN ? V OUT )
V IN × f S × I LOAD ( MAX ) × LIR
where f S is the switching frequency. Choose a stan-
dard-value inductor close to the calculated value. The
exact inductor value is not critical and can be adjusted
to make trade-offs among size, cost, and efficiency.
Setting the Switching Frequency
To set the switching frequency, connect a resistor from
FSYNC to GND. Calculate the resistor value in k ? from
the following equation:
30600
f S
where f S is the desired switching frequency in kHz.
Setting the Slope Compensation
For most applications where the duty cycle is less than
40%, connect SCOMP to GND to set the internal slope
compensation to the default of 125mV/T, where T is the
oscillator period (T = 1/f S ).
For a slope compensation of 250mV/T, connect
SCOMP to AVL.
For applications with a duty cycle greater than 40%, set
the SCOMP voltage with a resistor voltage-divider from
AVL to GND (R11 and R12 in Figure 6). First, use the
following equation to find the SCOMP voltage:
V SCOMP = × ( V OUT ? 0 . 182 × V IN _ MIN )
where R L is the DC resistance of the inductor, V IN_MIN
is the minimum operating input voltage, and f S is the
switching frequency.
Next, select a value for R11, typically 10k ? , and solve
for R12 as follows:
Lower inductor values minimize size and cost, but they
also increase the output ripple and reduce the efficien-
cy due to higher peak currents. On the other hand,
higher inductor values increase efficiency, but eventu-
R 12 =
( 5V ? V SCOMP ) × R11
V SCOMP
ally resistive losses due to extra turns of wire exceed
the benefit gained from lower AC current levels. This is
especially true if the inductance is increased without
also increasing the physical size of the inductor. Find a
low-loss inductor having the lowest possible DC resis-
tance that fits the allotted dimensions. The chosen
inductor’s saturation current rating must exceed the
This sets the internal slope-compensation voltage rate
to V SCOMP /(10 x T).
AVL
peak inductor current determined as:
MAX8655
R12
I PEAK = I LOAD ( MAX ) +
LIR
2
× I LOAD ( MAX )
SCOMP
R11
Figure 6. Resistor-Divider for Setting the Slope Compensation
______________________________________________________________________________________
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| MAX8655EVKIT+ | 功能描述:电源管理IC开发工具 MAX8655/88 Eval Kit 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 |
| MAX8657 | 功能描述:电流型 PWM 控制器 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 |
| MAX8658 | 功能描述:电流型 PWM 控制器 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 |
| MAX8659 | 功能描述:电流型 PWM 控制器 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 |
| MAX8659ETL+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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