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参数资料
| 型号： | MAX5072ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 12/27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
Detailed Description
PWM Controller
The MAX5072 converter uses a pulse-width modulation
(PWM) voltage-mode control scheme for each out-of-
phase controller. It is nonsynchronous rectification and
uses an external low-forward-drop Schottky diode for
rectification. The controller generates the clock signal
by dividing down the internal oscillator or the SYNC
input when driven by an external clock, so each con-
troller’s switching frequency equals half the oscillator
frequency (f SW = f OSC / 2). An internal transconduc-
tance error amplifier produces an integrated error volt-
age at the COMP pin, providing high DC accuracy. The
voltage at COMP sets the duty cycle using a PWM
comparator and a ramp generator. At each rising edge
of the clock, converter 1’s high-side n-channel MOSFET
turns on and remains on until either the appropriate or
maximum duty cycle is reached, or the maximum cur-
rent limit for the switch is detected. Converter 2 oper-
ates out-of-phase, so the second high-side MOSFET
turns on at each falling edge of the clock.
In the case of buck operation (Figure 1), during each
high-side MOSFET’s on-time, the associated inductor
current ramps up. During the second half of the switch-
ing cycle, the high-side MOSFET turns off and forward
biases the Schottky rectifier. During this time, the
SOURCE voltage is clamped to 0.4V (V D ) below
ground. The inductor releases the stored energy as its
current ramps down, and provides current to the out-
put. The bootstrap capacitor is also recharged from the
inductance energy when the MOSFET turns off. The cir-
cuit goes in discontinuous conduction mode operation
at light load, when the inductor current completely dis-
charges before the next cycle commences. Under
25 × 10 9
R OSC =
f OSC
where f OSC is the internal oscillator frequency in hertz
and R OSC in ohms.
The two independent regulators in the MAX5072 switch
180° out-of-phase to reduce input filtering require-
ments, to reduce electromagnetic interference (EMI),
and to improve efficiency. This effectively lowers com-
ponent cost and saves board space, making the
MAX5072 ideal for cost-sensitive applications.
With dual synchronized out-of-phase operation, the
MAX5072’s high-side MOSFETs turn on 180° out-of-
phase. The instantaneous input current peaks of both
regulators do not overlap, resulting in reduced RMS rip-
ple current and input voltage ripple. This reduces the
required input capacitor ripple current rating, allows for
fewer or less expensive capacitors, and reduces
shielding requirements for EMI. The out-of-phase wave-
forms in the Typical Operating Characteristics demon-
strate synchronized 180° out-of-phase operation.
Synchronization (SYNC)/Clock
Output (CLKOUT)
The main oscillator can be synchronized to the system
clock by applying an external clock (f SYNC ) at SYNC.
The f SYNC frequency must be twice the required oper-
ating frequency of an individual converter. Use a TTL
logic signal for the external clock with at least a 100ns
pulse width. R OSC is still required when using external
synchronization. Program the internal oscillator fre-
quency so 0.2f SYNC < f OSC < 1.2f SYNC . The rising
edge of f SYNC synchronizes the turn-on edge of internal
MOSFET (see Figure 3).
overload conditions, when the inductor current exceeds
the peak current limit of the respective switch, the high-
side MOSFET turns off quickly and waits until the next
clock cycle.
R OSC =
25 × 10 9
f OSC
In the case of boost operation, the MOSFET is a low-
side switch (Figure 9). During each on-time, the induc-
tor current ramps up. During the second half of the
switching cycle, the low-side switch turns off and for-
ward biases the Schottky diode. During this time the
DRAIN voltage is clamped to 0.4V (V D ) above V OUT_
and the inductor provides energy to the output as well
as replenishes the output capacitor charge.
Internal Oscillator/Out-of-Phase Operation
The internal oscillator generates the 180° out-of-phase
clock signal required by each regulator. The internal
oscillator frequency is programmable from 400kHz to
4.4MHz using a single 1% resistor at R OSC . Use the fol-
lowing equation to calculate R OSC :
where f OSC is the internal oscillator frequency in hertz
and R OSC in ohms, f OSC = 2 x f SW .
Two MAX5072s can be connected in master-slave con-
figuration for four ripple-phase operation. The MAX5072
provides a clock output (CLKOUT) that is 45° phase-
shifted with respect to the internal switch turn-on edge.
Feed the CLKOUT of the master to the SYNC input of
the slave. The effective input ripple switching frequency
shall be four times the individual converter’s switching
frequency. When driving the master converter using
external clock at SYNC, set the clock duty cycle to 50%
for a 90° phase-shifted operation.
12
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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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