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| 型号： | MAX15048ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 21/31页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM STP-DN TRIPL 32WQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 应用： | 电源控制器，序列发生器 |
| 电源电压： | 4.7 V ~ 23 V |
| 电流 - 电源： | 6mA |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 管件 |
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MAX15048/MAX15049
Triple-Output Buck Controllers
with Tracking/Sequencing
Use the following equations to calculate the required
ESR, ESL, and capacitance value during a load step:
Power-MOSFET Selection
When choosing the n-channel MOSFETs, consider the
ESR =
? V ESR
I STEP
total gate charge, R DS(ON) , power dissipation, the
maximum drain-to-source voltage, and package thermal
impedance. The product of the MOSFET gate charge
and on-resistance is a figure of merit, with a lower num-
? V ESL STEP
C OUT =
ESL =
I STEP × t RESPONSE
? V Q
× t
I STEP
ber signifying better performance. Choose MOSFETs that
are optimized for high-frequency switching applications.
The average gate-drive current from the MAX15048/
MAX15049s’ output is proportional to the frequency and
gate charge required to drive the MOSFET. The power
dissipated in the MAX15048/MAX15049 is proportional
to the input voltage and the average drive current (see
the Power Dissipation section).
t RESPONSE =
1
3 × f CO
Compensation Design Guidelines
The MAX15048/MAX15049 use a fixed-frequency, volt-
age-mode control scheme that regulates the output
where I STEP is the load step, t STEP is the rise time of the
load step, t RESPONSE is the response time of the con-
troller, and f CO is the closed-loop crossover frequency
of system (see the Compensation Design Guidelines
section).
Setting the Current Limit
The MAX15048/MAX15049 use a valley current-sense
method for current limiting. The valley current-limit
threshold (V LIM ) is internally set at 69mV (typ).
The voltage drop across the low-side MOSFET due to its
on-resistance is used to sense the inductor current. The
voltage drop (V VALLEY ) across the low-side MOSFET at
the valley point and at I LOAD is:
voltage by differentially comparing the “sampled” out-
put voltage against a fixed reference. The subsequent
“error” voltage—that appears at the error-amplifier output
(COMP_)—is compared against an internal ramp voltage
to generate the required duty cycle of the pulse-width
modulator. A 2nd-order lowpass LC filter removes the
switching harmonics and passes the DC component of
the pulse-width-modulated signal to the output. The LC
filter, which has an attenuation slope of -40dB/decade,
introduces 180° out-of-phase shift at frequencies above
the LC resonant frequency. This phase shift, in addi-
tion to the inherent 180° of phase shift of the regulator’s
self-governing (negative) feedback system, poses the
potential for positive feedback. The error amplifier and
its associated circuitry are designed to compensate for
VALLEY
V = R DS(ON) × (I LOAD(MAX) -
? I P-P
2
)
this instability in order to achieve a stable closed-loop
system.
The basic regulator loop consists of a power modula-
R DS(ON) is the on-resistance of the low-side MOSFET,
I LOAD is the rated load current, and D I P-P is the peak-to-
peak inductor current.
The R DS(ON) of the MOSFET varies with temperature.
Calculate the R DS(ON) of the MOSFET at its operating
junction temperature at full load using its data sheet. To
compensate for this temperature variation, the current-
limit circuitry has a temperature coefficient of 3333ppm/ N C.
This allows the valley current-limit threshold (V LIM ) to
track and partially compensate for the increase in the
R DS(ON) of the synchronous MOSFET with increasing
temperature.
Maxim Integrated
tor (comprising the regulator’s pulse-width modulator,
associated circuitry, and LC filter), an output feedback
divider, and an error amplifier. The power modulator has
a DC gain set by V IN /V RAMP , with a double pole and a
single zero set by the output inductance (L), the output
capacitance (C OUT ), and its ESR. A second, higher fre-
quency zero also exists, which is a function of the output
capacitor’s ESR and ESL, though only taken into account
when using very high-quality filter components and/or
frequencies of operation.
21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX15048ETJ+ | 功能描述:DC/DC 开关控制器 1.2MHz Triple Buck w/Tracking 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 |
| MAX15048ETJ+ | 制造商:Maxim Integrated Products 功能描述:IC, BUCK, CNTRL, TRIPLE, 32WQFN |
| MAX15048ETJ+ | 制造商:Maxim Integrated Products 功能描述:IC PWM STEP-DOWN DC/DC CONVER |
| MAX15048ETJ+T | 功能描述:DC/DC 开关控制器 1.2MHz Triple Buck w/Tracking 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 |
| MAX15049ETJ+ | 功能描述:DC/DC 开关控制器 1.2MHz Triple Buck w/Tracking 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 |
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