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参数资料
| 型号： | MAX1971EEE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 18/21页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC 0.75A DL 16QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 两者兼有 |
| 输出数： | 2 |
| 输出电压： | 1.5V，1.8V，2.5V，3.3V，可调 |
| 输入电压： | 2.6 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 700kHz |
| 电流 - 输出： | 750mA |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SSOP（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 16-QSOP |
Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step-
Down Regulator with POR and RSI/PFO
troller can respond, the output deviates further,
depending on the inductor and output capacitor
The zero frequency for the output capacitor ESR is:
values. After a short time (see the Typical Operating
Characteristics), the controller responds by regulating
the output voltage back to its nominal state. The con-
fz ESR =
1
2 π × C OUT × ESR
troller response time depends on the closed-loop
bandwidth. With a higher bandwidth, the response time
is faster, thus preventing the output from deviating fur-
ther from its regulating value.
Compensation Design
An internal transconductance error amplifier is used to
compensate the control loop. Connect a series resistor
and capacitor between COMP and GND to form a pole-
zero pair. The external inductor, internal high-side
MOSFET, output capacitor, compensation resistor, and
compensation capacitor determine the loop stability.
where, R LOAD = V OUT /I OUT(MAX) , and GMC = 2μS. The
feedback divider has a gain of G FB = V FB /V OUT , where
V FB is equal to 1.2V. The transconductance error ampli-
fier has a DC gain, G EA(DC) , of 60dB. A dominant pole
is set by the compensation capacitor, C C , the output
resistance of the error amplifier (R OEA ), 20M ? , and the
compensation resistor, R C . A zero is set by R C and C C .
The pole frequency set by the transconductance ampli-
fier output resistance, and compensation resistor and
capacitor is:
The inductor and output capacitor are chosen based
on performance, size, and cost. Additionally, the com-
pensation resistor and capacitor are selected to opti-
mize control-loop stability. The component values
fp EA =
1
2 π × C C × R OEA
shown in the typical application circuits (Figures 3, 4,
and 5) yield stable operation over a broad range of
input-to-output voltages.
The zero frequency set by the compensation capacitor
and resistor is:
The controller uses a current-mode control scheme that
regulates the output voltage by forcing the required
current through the external inductor. The voltage
fz EA =
1
2 π × C C × R C
G EA ( fc ) × G MOD ( fc ) × = 1
across the internal high-side MOSFET’s on-resistance
(R DS(ON) ) is used to sense the inductor current. Current
mode control eliminates the double pole caused by the
inductor and output capacitor, which has large phase
shift that requires more elaborate error-amplifier com-
pensation. A simple Type 1 compensation with single
compensation resistor (R C ) and compensation capaci-
tor (C C ) is all that is needed to have a stable and high-
bandwidth loop.
The basic regulator loop consists of a power modulator,
an output feedback divider, and an error amplifier. The
power modulator has DC gain set by gmc x R LOAD ,
with a pole and zero pair set by R LOAD , the output
capacitor (C OUT ), and its ESR. Below are equations
that define the power modulator:
For best stability and response performance, the
closed-loop unity-gain frequency must be much higher
than the modulator pole frequency. In addition, the
closed-loop unity-gain frequency should be approxi-
mately 50kHz. The loop gain equation at unity gain fre-
quency then is:
V FB
V O
Where G EA(fc) = gm EA R C , and G MOD(fc) = gmc
R LOAD fp MOD / fc , where gm EA = 50μS, R C can be
calculated as:
G MOD = gmc × R LOAD
The pole frequency for the modulator is:
R C =
V O
gm EA × V FB × G MOD ( fc )
fp MOD =
1
2 π × C OUT × ( R LOAD + ESR )
The error-amplifier compensation zero formed by R C
and C C is set at the modulator pole frequency at maxi-
mum load. C C is calculated as follows:
C OUT
C C = V OUT ×
R C × I OUT ( MAX )
18
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1972EEE | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX1972EEE+ | 功能描述:直流/直流开关调节器 Dual 180 Out 1.4MHz 750mA Step-Down RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX1972EEE+T | 功能描述:直流/直流开关调节器 Dual 180 Out 1.4MHz 750mA Step-Down RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX1972EEE-G05 | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1972EEE-T | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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