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| 型号： | MAX15049ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 19/31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
Consequently, peak currents and I 2 R losses are lower
at higher switching frequencies, but core losses, gate-
IN
CURRENT LIMIT
COUNT OF 8
N CL
CLR
INITIATE HICCUP
TIMEOUT
N HT
charge currents, and switching losses increase.
Effective Input Voltage Range
Although the MAX15048/MAX15049 converters can
operate from input supplies ranging from 4.7V to 23V,
the input voltage range can be effectively limited by the
duty-cycle limitations for a given output voltage. The
IN
COUNT OF 3
N CLR
CLR
maximum input voltage is limited by the minimum on-
time (t ON(MIN) ):
Figure 3. Hiccup-Mode Block Diagram
V IN(MAX) ≤
V OUT_
t ON(MIN) × f SW
just before the beginning of a new PWM cycle, the con-
troller skips that cycle. During severe overload or short-
circuit conditions, the switching frequency of the device
appears to decrease because the on-time of the low-side
MOSFET extends beyond a clock cycle.
where t ON(MIN) is 75ns.
The minimum input voltage is limited by the maximum
duty cycle and is calculated using the following equa-
tion:
If the current-limit threshold is exceeded for more than
eight cumulative clock cycles (N CL ), the device shuts
down (both DH_ and DL_ are pulled low) for 4096 clock
V IN(MIN) =
V OUT_
1-(t OFF(MIN) × f SW )
L = OUT_ IN OUT_
cycles (hiccup timeout) and then restarts with a soft-
start sequence. If three consecutive cycles pass without
a current-limit event, the count of N CL is cleared (see
Figure 3). Hiccup mode protects the circuit against a
continuous output short circuit.
Thermal-Overload Protection
The MAX15048/MAX15049 feature an integrated ther-
mal-overload protection with temperature hysteresis.
Thermal-overload protection limits the total power dis-
sipation in the device and protects it in the event of an
extended thermal-fault condition. When the die tempera-
ture exceeds +160 N C (typ), an internal thermal sensor
shuts down the device, turning off the power MOSFETs
and allowing the die to cool. After the die temperature
falls by +20 N C (typ), the part restarts with a soft-start
sequence.
Design Procedure
Setting the Switching Frequency
Connect a 15.625k I to 93.75k I resistor from RT to
SGND to program the switching frequency from 200kHz
to 1.2MHz. Calculate the switching frequency using the
following equation:
f SW (kHz) = 12.8 O R RT (k I )
Higher switching frequencies allow designs with
lower inductor values and less output capacitance.
Maxim Integrated
where t OFF(MIN) typically is equal to 300ns.
Inductor Selection
Three key inductor parameters must be specified for
operation with the MAX15048/MAX15049: inductance
value (L), inductor saturation current (I SAT ), and induc-
tor series resistance (DCR). The minimum required
inductance is a function of operating frequency, input-to-
output voltage differential, and the peak-to-peak inductor
current ( D I P-P ). Higher D I P-P allows for a lower inductor
value. A lower inductance value minimizes size and
cost and improves large-signal and transient response.
However, efficiency is reduced due to higher peak cur-
rents and higher peak-to-peak output-voltage ripple for
the same output capacitor. A higher inductance increas-
es efficiency by reducing the ripple current; however,
resistive losses due to extra wire turns can exceed the
benefit gained from lower ripple current levels, especial-
ly when the inductance is increased without also allow-
ing for larger inductor dimensions. A good rule of thumb
is to choose D I P-P equal to 30% of the full load current.
Calculate the inductance using the following equation:
V (V - V )
V IN × f SW × ? I P-P
V IN and V OUT_ are typical values so that efficiency is
optimum for typical conditions. The switching frequency
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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 |
| MAX15049ETJ+ | 制造商:Maxim Integrated Products 功能描述:IC BUCK CNTRL TRIPLE 32WQFN 制造商:Maxim Integrated Products 功能描述:IC, BUCK, CNTRL, TRIPLE, 32WQFN |
| MAX15049ETJ+ | 制造商:Maxim Integrated Products 功能描述:IC PWM STEP-DOWN DC/DC CONVER |
| MAX15049ETJ+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 |
| MAX15049EVKIT+ | 功能描述:电源管理IC开发工具 MAX15049 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 |
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