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参数资料
| 型号： | MAX5072ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 17/27页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK BST ADJ 1A/2A 32TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 类型： | 降压（降压），升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 2 |
| 输出电压： | 0.8 V ~ 28 V |
| 输入电压： | 4.5 V ~ 23 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 200kHz ~ 2.2MHz |
| 电流 - 输出： | 1A，2A |
| 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： | 32-WFQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
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2.2MHz, Dual-Output Buck or Boost
Converter with POR and Power-Fail Output
In deep overload or short-circuit conditions when the
FB voltage drops below 0.4V, the switching frequency
is reduced to 1/4 x f SW to provide sufficient time for the
inductor to discharge. During overload conditions, if the
voltage across the inductor is not high enough to allow
for the inductor current to properly discharge, current
runaway may occur. Current runaway can destroy the
LX_
FB_
R A
BYPASS
FB_
R C
device in spite of internal thermal-overload protection.
Reducing the switching frequency during overload con-
ditions prevents current runaway.
MAX5072
R B
MAX5072
LX_
R A
Thermal-Overload Protection
During continuous short circuit or overload at the out-
V OUT_ > 0.8V
V OUT_ < 0.8V
put, the power dissipation in the IC can exceed its limit.
Internal thermal shutdown is provided to avoid irre-
versible damage to the device. When the die tempera-
ture or junction temperature exceeds +150°C, an
on-chip thermal sensor shuts down the device, forcing
the internal switches to turn off, allowing the IC to cool.
The thermal sensor turns the part on again after the
junction temperature cools by +30°C. During thermal
shutdown, both regulators shut down, RST goes low,
and soft-start resets.
Figure 6. Adjustable Output Voltage
Buck Converter
Effective Input Voltage Range
Although the MAX5072 converters can operate from
input supplies ranging from 4.5V to 23V, the input volt-
age range can be effectively limited by the MAX5072
duty-cycle limitations for a given output voltage. The
maximum input voltage is limited by the minimum on-
time (t ON(MIN) ):
Applications Information
Setting the Switching Frequency
The controller generates the clock signal by dividing
V IN ( MAX ) ≤
V OUT
t ON ( MIN ) × f SW
V IN ( MIN ) = ? OUT DROP 1 ? + V DROP 2 ? V DROP 1
?
?
down the internal oscillator or the SYNC input signal
when driven by an external oscillator. The switching
frequency equals half the oscillator frequency (f SW =
f OSC / 2). The internal oscillator frequency is set by a
resistor (R OSC ) connected from OSC to SGND. The
relationship between f SW and R OSC is:
where t ON(MIN) is 100ns. The minimum input voltage is
limited by the maximum duty cycle (D MAX = 0.88):
? V + V ?
0 . 88
R OSC =
12.5 × 10 9
f SW
where V DROP1 is the total parasitic voltage drops in the
inductor discharge path, which includes the forward
voltage drop (V D ) of the rectifier, the series resistance of
the inductor, and the PC board resistance. V DROP2 is
R A = R B ? ? OUT ? ? 1 ?
where f SW and f OSC are in hertz, and R OSC is in ohms.
For example, a 1250kHz switching frequency is set with
R OSC = 10k ? . Higher frequencies allow designs with
lower inductor values and less output capacitance.
Consequently, peak currents and I 2 R losses are lower
at higher switching frequencies, but core losses, gate-
charge currents, and switching losses increase.
A rising clock edge on SYNC is interpreted as a syn-
chronization input. If the SYNC signal is lost, the inter-
nal oscillator takes control of the switching rate,
returning the switching frequency to that set by R OSC .
This maintains output regulation even with intermittent
SYNC signals. When an external synchronization signal
is used, R OSC should be set for the oscillator frequency
to be lower than or equal to the SYNC rate (f SYNC ).
the total resistance in the charging path, which includes
the on-resistance of the high-side switch, the series
resistance of the inductor, and the PC board resistance.
Setting the Output Voltage
For 0.8V or greater output voltages, connect a voltage-
divider from OUT_ to FB_ to SGND (Figure 6). Select
R B (FB_ to SGND resistor) to between 1k ? and 10k ? .
Calculate R A (OUT_ to FB_ resistor) with the following
equation:
? ? V ? ?
? ?
? ? V FB ? ?
where V FB_ = 0.8V (see the Electrical Characteristics table)
and V OUT_ can range from V FB_ to 28V (boost operation).
______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5072ETJ+ | 功能描述:直流/直流开关转换器 2.2MHz Buck or Boost Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX5072ETJ+T | 功能描述:直流/直流开关转换器 2.2MHz Buck or Boost Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX5072ETJ-T | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX5072EVKIT | 功能描述:电源管理IC开发工具 2.2MHz Buck or Boost Converter 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 |
| MAX5073 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs |
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