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参数资料
| 型号： | MAX1842EEE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC 1A 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： | 1 |
| 输出电压： | 1.5V，1.8V，2.5V，可调 |
| 输入电压： | 3 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 1A |
| 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 |
1A/2.7A, 1MHz, Step-Down Regulators with
Synchronous Rectification and Internal Switches
The peak inductor current at full load is 1.125 x I OUT if
the above equation is used; otherwise, the peak current
is calculated by:
I PEAK = I OUT +
V OUT × t OFF
2 × L
SHDN
0
1.8V
Choose an inductor with a saturation current at least as
high as the peak inductor current. The inductor you
V SS (V)
0
0.7V
select should exhibit low losses at your chosen operat-
ing frequency.
Capacitor Selection
The input filter capacitor reduces peak currents and
noise at the voltage source. Use a low-ESR and low-
ESL capacitor located no further than 5mm from IN.
Select the input capacitor according to the RMS input
ripple-current requirements and voltage rating:
I LIMIT (A)
0
Figure 5. Soft-Start Current Limit over Time
I LIMIT
t
I RIPPLE = I LOAD
V OUT ( V IN ? V OUT
V IN
)
decreases stability. Choose the capacitor values that
result in optimal performance.
where I RIPPLE = input RMS current ripple.
The output filter capacitor affects the output voltage rip-
ple, output load-transient response, and feedback loop
stability. For stable operation, the MAX1742/MAX1842
requires a minimum output ripple voltage of V RIPPLE ≥
1% x V OUT .
The minimum ESR of the output capacitor should be:
Soft-Start
Soft-start allows a gradual increase of the internal cur-
rent limit to reduce input surge currents at startup and
at exit from shutdown. A timing capacitor, C SS , placed
from SS to GND sets the rate at which the internal cur-
rent limit is changed. Upon power-up, when the device
comes out of undervoltage lockout (2.6V typ) or after
the SHDN pin is pulled high, a 4μA constant-current
ESR > 1 % ×
L
t OFF
source charges the soft-start capacitor and the voltage
on SS increases. When the voltage on SS is less than
approximately 0.7V, the current limit is set to zero. As
C OUT ≥ OFF 33 μ FV / μ s for the MAX 1742
C OUT ≥ OFF 79 μ FV / μ s for the MAX 1842
V SS =
SSI LIMIT = SS
× I LIMIT
Stable operation requires the correct output filter capaci-
tor. When choosing the output capacitor, ensure that:
t
V OUT
t
V OUT
Integrator Amplifier
An internal transconductance amplifier fine tunes the
output DC accuracy. A capacitor, C COMP , from COMP
to V CC compensates the transconductance amplifier.
For stability, choose C COMP = 470pF.
A large capacitor value maintains a constant average
output voltage but slows the loop response to changes
in output voltage. A small capacitor value speeds up
the loop response to changes in output voltage but
the voltage increases from 0.7V to approximately 1.8V,
the current limit is adjusted from 0 to the current-limit
threshold (see the Electrical Characteristics ).The volt-
age across the soft-start capacitor changes with time
according to the equation:
4 μ A × t
C SS
The soft-start current limit varies with the voltage on the
soft-start pin, SS, according to the equation:
V ? 0.7V
1 . 1 V
where I LIMIT is the current threshold from the Electrical
Characteristics .
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相关代理商/技术参数 |
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| MAX1842EEE-TG074 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1843EGI | 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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| MAX1843EGI+T | 制造商:Maxim Integrated Products 功能描述:CONV DC-DC SGL-OUT STEP DOWN 28QFN EP - Tape and Reel |
| MAX1843EGI-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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