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参数资料
| 型号： | MAX15026CATD+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 15/23页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 14TDFN |
| 产品培训模块： | Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 2.4MHz |
| 占空比： | 88% |
| 电源电压： | 4.5 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 ~ 125°C |
| 封装/外壳： | 14-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
MAX15026
Low-Cost, Small, 4.5V to 28V Wide Operating
Range, DC-DC Synchronous Buck Controller
requirements. Choose the small-signal components for
the error amplifier to achieve the desired closed-loop
bandwidth and phase margin.
To choose the appropriate compensation network type,
the power-supply poles and zeros, the zero crossover
frequency, and the type of the output capacitor must be
determined.
In a buck converter, the LC filter in the output stage intro-
duces a pair of complex poles at the following frequency:
Type II Compensation Network
(Figure 3)
If f ZO is lower than f O and close to f PO , the phase lead
of the capacitor ESR zero almost cancels the phase
loss of one of the complex poles of the LC filter around
the crossover frequency. Use a Type II compensation
network with a midband zero and a high-frequency
pole to stabilize the loop. In Figure 3, R F and C F intro-
duce a midband zero (f Z1 ). R F and C CF in the Type II
compensation network provide a high-frequency pole
f PO =
1
2 π × L OUT × C OUT
(f P1 ), which mitigates the effects of the output high-fre-
quency ripple.
Follow the instructions below to calculate the component
The output capacitor introduces a zero at:
values for the Type II compensation network in Figure 3:
f ZO =
1
2 π × ESR × C OUT
1) Calculate the gain of the modulator (GAIN MOD ),
comprised of the regulator’s pulse-width modulator,
LC filter, feedback divider, and associated circuitry
at the crossover frequency:
where ESR is the equivalent series resistance of the
×
output capacitor.
The loop-gain crossover frequency (f O ), where the loop
gain equals 1 (0dB) should be set below 1/10th of the
GAIN MOD =
V IN ESR
V RAMP ( 2 π × f O × L OUT )
×
V FB
V OUT
f O ≤ SW
switching frequency:
f
10
Choosing a lower crossover frequency reduces the
effects of noise pick-up into the feedback loop, such as
jittery duty cycle.
To maintain a stable system, two stability criteria must
be met:
1) The phase shift at the crossover frequency f O , must
be less than 180°. In other words, the phase margin
of the loop must be greater than zero.
2) The gain at the frequency where the phase shift is
-180° (gain margin) must be less than 1.
where V IN is the input voltage of the regulator, V RAMP is
the amplitude of the ramp in the pulse-width modulator,
V FB is the FB input voltage set-point (0.591V typically,
see the Electrical Characteristics table), and V OUT is
the desired output voltage.
The gain of the error amplifier (GAIN EA ) in midband fre-
quencies is:
GAIN EA = g M x R F
where g M is the transconductance of the error amplifier.
The total loop gain, which is the product of the modula-
tor gain and the error amplifier gain at f O , is 1.
GAIN MOD × GAIN EA = 1
So:
× × g M F = 1
× R
Maintain a phase margin of around 60° to achieve a
robust loop stability and well-behaved transient
response.
V IN
V RAMP
×
ESR
( 2 π × f O × L OUT )
V FB
V OUT
× ( 2 π × f × L ) × V
R F = RAMP O OUT OUT
When using an electrolytic or large-ESR tantalum output
capacitor the capacitor ESR zero f ZO typically occurs
between the LC poles and the crossover frequency f O
(f PO < f ZO < f O ). Choose Type II (PI—proportional-inte-
gral) compensation network.
When using a ceramic or low-ESR tantalum output
capacitor, the capacitor ESR zero typically occurs
Solving for R F :
V
V FB × V IN × g M × ESR
2) Set a midband zero (f Z1 ) at 0.75 x f PO (to cancel
one of the LC poles):
above the desired crossover frequency f O , that is f PO <
f O < f ZO . Choose Type III (PID—proportional, integral,
and derivative) compensation network.
Maxim Integrated
f Z 1 =
1
2 π × R F × C F
= 0 . 75 × f PO
15
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| MAX15026CETD+ | 功能描述:DC/DC 开关控制器 4.5-28V Synchronous Buck Controller 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 |
| MAX15026CETD+G1D | 制造商:Maxim Integrated Products 功能描述:LOW-COST, SMALL, 4.5V TO 28V WIDE OPERATING RANGE, DC-DC SYN - Rail/Tube |
| MAX15026CETD+T | 功能描述:DC/DC 开关控制器 4.5-28V Synchronous Buck Controller 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 |
| MAX15026CETD+TG1D | 制造商:Maxim Integrated Products 功能描述:LOW-COST, SMALL, 4.5V TO 28V WIDE OPERATING RANGE, DC-DC SYN - Tape and Reel |
| MAX15026CETD+TW | 制造商:Maxim Integrated Products 功能描述:LOW-COST SMALL 4.5V TO 28V WIDE OPERATING RANGE DC-DC CONT - Tape and Reel |
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