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参数资料
| 型号： | MAX5081ATE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/19页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1A 16TQFN |
| 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） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.23 V ~ 32 V |
| 输入电压： | 7.5 V ~ 40 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 250kHz |
| 电流 - 输出： | 1A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 16-TQFN-EP（5x5） |
1A, 40V, MAXPower Step-Down
DC-DC Converters
equal to 20% and 80%, respectively. ? I P-P is the peak-to-
peak inductor current (see the Input Capacitors Selection
section) and f SW is the converter’s switching frequency.
The allowable deviation of the output voltage during
fast load transients also determines the output capaci-
tance, its ESR, and its equivalent series inductance
(ESL). The output capacitor supplies the load current
(C OUT ) (C5 in the Typical Application Circuit ) and its
equivalent series resistance (ESR). The power modula-
tor incorporates a voltage feed-forward feature, which
automatically adjusts for variations in the input voltage
resulting in a DC gain of 10. The following equations
define the power modulator:
during a load step until the controller responds with a
greater duty cycle. The response time (t RESPONSE )
depends on the closed-loop bandwidth of the converter
G MOD ( DC ) =
V IN
V RAMP
= 10
(see the Compensation Design section). The resistive
drop across the output capacitors ESR, the drop
across the capacitors ESL ( ? V ESL) , and the capacitor
discharge causes a voltage droop during the load-
step. Use a combination of low-ESR tantalum/aluminum
f LC =
1
2 π L × C OUT
electrolyte and ceramic capacitors for better transient
load and voltage ripple performance. Nonleaded
capacitors and capacitors in parallel help reduce the
f ZESR =
1
2 π × C OUT × ESR
ESL. Keep the maximum output voltage deviation
below the tolerable limits of the electronics being pow-
ered. Use the following equations to calculate the
required ESR, ESL, and capacitance value during a
load step:
The switching frequency is internally set at 250kHz or
can vary from 150kHz to 350kHz when driven with an
external SYNC signal. The crossover frequency (f C ),
which is the frequency when the closed-loop gain is
equal to unity, should be set at 15kHz or below therefore:
E SR =
C OUT =
? V ESR
I STEP
I STEP × t RESPONSE
? V Q
f C ≤ 15kHz
The error amplifier must provide a gain and phase
bump to compensate for the rapid gain and phase loss
from the LC double pole. This is accomplished by utiliz-
ing a type 3 compensator that introduces two zeroes
and 3 poles into the control loop. The error amplifier
has a low-frequency pole (f P1 ) near the origin.
? V ESL × t STEP
f Z1 =
and f Z2 =
E SL =
I STEP
where I STEP is the load step, t STEP is the rise time of the
load step, and t RESPONSE is the response time of the
controller.
The two zeros are at:
1 1
2 π × R 5 × C 7 2 π × ( R 6 + R 3 ) × C 6
and the higher frequency poles are at:
2 π × R 5 × ?
? C 7 + C 8 ?
Compensation Design
The MAX5080/MAX5081 use a voltage-mode control
scheme that regulates the output voltage by comparing
the error amplifier output (COMP) with an internal ramp
f P 2 =
1
2 π × R 6 × C 6
and f P 3 =
1
? C7 × C8 ?
?
to produce the required duty cycle. The output lowpass
LC filter creates a double pole at the resonant frequen-
cy, which has a gain drop of -40dB/decade. The error
amplifier must compensate for this gain drop and phase
shift to achieve a stable closed-loop system.
The basic regulator loop consists of a power modulator,
an output feedback divider, and a voltage error amplifi-
er. The power modulator has a DC gain set by
V IN /V RAMP , with a double pole and a single zero set by
the output inductance (L), the output capacitance
Compensation When f C < f ZESR
Figure 3 shows the error amplifier feedback as well as
its gain response for circuits that use low-ESR output
capacitors (ceramic). In this case f ZESR occurs after f C .
f Z1 is set to 0.8 x f LC(MOD) and f Z2 is set to f LC to com-
pensate for the gain and phase loss due to the double
pole. Choose the inductor (L) and output capacitor
(C OUT ) as described in the Inductor and Output
Capacitor Selection section.
______________________________________________________________________________________
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5081ATE+ | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down 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 |
| MAX5081ATE+T | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down 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 |
| MAX5081ATE-T | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down 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 |
| MAX5082 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:1.5A, 40V, MAXPower Step-Down DC-DC Converters |
| MAX5082ATE | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down 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 |
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