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| 型号： | MAX8548EUB+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/18页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 10-UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 120kHz |
| 占空比： | 95% |
| 电源电压： | 2.7 V ~ 28 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 管件 |
Low-Cost, Wide Input Range, Step-Down
Controllers with Foldback Current Limit
has a gain drop of 40dB per decade, and a phase shift
of 180°. The error amplifier must compensate for this
gain drop and phase shift to achieve a stable high-
The compensation resistor and the compensation
capacitor set a zero:
bandwidth, closed-loop system.
The basic regulator loop consists of a power modulator
f ZEA =
1
2 π × C C × R C
G MOD ( DC ) =
f ZESR C ≤ SW
< f
f PMOD =
(Figure 3), an output feedback divider, and an error
amplifier. The power modulator has DC gain set by
V IN /V RAMP , with a double pole set by the inductor and
output capacitor, and a single zero set by the output
capacitor (C OUT ) and its equivalent series resistance
(ESR). Below are equations that define the power mod-
ulator:
The DC gain of the power modulator is:
V IN
V RAMP
where V RAMP = 1V.
The pole frequency due to the inductor and output
capacitor is:
1
2 π LC OUT
The zero frequency due to the output capacitor’s ESR is:
The total closed-loop gain must equal unity at the
crossover frequency. The crossover frequency should
be higher than f ZESR , so that the -1 slope is used to
cross over at unity gain. Also, the crossover frequency
should be less than or equal to 1/5 the switching fre-
quency (f SW ) of the controller:
f
5
The loop-gain equation at the crossover frequency is:
V FB /V OUT x G EA(f C ) x G MOD(f C ) = 1
where G EA(f C ) = g mEA × R C , and G MOD(f C ) =
G MOD(DC) × (f PMOD ) 2 / (f ZESR × f C ).
The compensation resistor, R C , is calculated from:
R C = V OUT / g mEA x V FB x G MOD(f C )
where g mEA = 108μS.
Due to the underdamped (Q > 1) nature of the output
f ZESR =
1
2 π × ESR × C OUT
LC double pole, the error-amplifier compensation zero
should be approximately 0.2 f PMOD to provide good
phase boost. C C is calculated from:
The output capacitor is usually comprised of several
same capacitors connected in parallel. With n capaci-
tors in parallel, the output capacitance is:
C C =
5
2 π × R C × f PMOD
The total ESR is:
C OUT = n x C EACH
A small capacitor, C F , can also be added from COMP to
GND to provide high-frequency decoupling. C F adds
ESR =
ESR EACH
n
another high-frequency pole, f PHF , to the error-amplifier
response. This pole should be greater than 100 times the
error-amplifier zero frequency to have negligible impact
The ESR zero (f ZESR ) for a parallel combination of
capacitors is the same as for an individual capacitor.
The feedback divider has a gain of G FB = V FB /V OUT ,
where V FB is 0.8V.
The transconductance error amplifier has DC gain
on the phase margin. This pole should also be less than
1/2 the switching frequency for effective decoupling:
100 f ZEA < f PHF < 0.5 f sw
Select a value for f PHF in the range given above, then
solve for C F using the following equation:
G EA(dc) of 72dB. A dominant pole (f DPEA ) is set by the
compensation capacitor (C C ), the amplifier output
resistance (R O ) equals 37M Ω , and the compensation
resistor (R C ):
C F =
1
2 π × R C × f PHF
f DPEA =
1
2 π × C C × ( R O + R C )
PCB Layout Guidelines
Careful PCB layout is critical to achieve low switching
losses and stable operation. If possible, mount all the
power components on the top side of the board with their
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8548EUB+ | 功能描述:电压模式 PWM 控制器 Wide Input Range Step-Down Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX8548EUB+T | 功能描述:电压模式 PWM 控制器 Wide Input Range Step-Down Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX8548EUB-T | 功能描述:DC/DC 开关控制器 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 |
| MAX8550AETI | 功能描述:PMIC 解决方案 RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| MAX8550AETI+ | 功能描述:电压模式 PWM 控制器 Integrated DDR Power Supply Solution RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
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