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| 型号： | MAX1644EAE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 9/11页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 2A 16SSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 76 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.1 V ~ 5.5 V |
| 输入电压： | 3 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 最高 350kHz |
| 电流 - 输出： | 2A |
| 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（0.209"，5.30mm 宽） |
| 包装： | 管件 |
| 供应商设备封装： | 16-SSOP |
| 产品目录页面： | 1410 (CN2011-ZH PDF) |
2A, Low-Voltage, Step-Down Regulator with
Synchronous Rectification and Internal Switches
f PWM = switching frequency in PWM mode
(I OUT > 0.2A)
Select R TOFF according to the formula:
R TOFF = (t OFF - 0.07μs) (150k Ω / 1.26μs)
Recommended values for R TOFF range from 39k Ω to
470k Ω for off-times of 0.4μs to 4μs.
The output filter capacitor affects the output voltage rip-
ple, output load-transient response, and feedback loop
stability. For stable operation, the MAX1644 requires a
minimum output ripple voltage of V RIPPLE ≥ 2% · V OUT
(with 2% load regulation setting).
The minimum ESR of the output capacitor should be:
Inductor Selection
Three key inductor parameters must be specified:
ESR > 1 % ×
L
t OFF
inductor value (L), peak current (I PEAK ), and DC resis-
tance (R DC ). The following equation includes a con-
stant, denoted as LIR, which is the ratio of peak-
to-peak inductor AC current (ripple current) to maxi-
mum DC load current. A higher value of LIR allows
smaller inductance but results in higher losses and rip-
ple. A good compromise between size and losses is
found at approximately a 25% ripple-current to load-
current ratio (LIR = 0.25), which corresponds to a peak
inductor current 1.125 times higher than the DC load
current:
Stable operation requires the correct output filter
capacitor. When choosing the output capacitor, ensure
that:
C OUT ≥ (t OFF / V OUT ) ? (64μFV / μs)
With an AC load regulation setting of 1%, the C OUT
requirement doubles, and the minimum ESR of the out-
put capacitor is halved.
Integrator Amplifier
An internal transconductance amplifier fine tunes the
L =
V OUT × t OFF
I OUT × LIR
output DC accuracy. A capacitor, C COMP , from COMP
to V CC compensates the transconductance amplifier.
For stability, choose:
C COMP ≥ 470pF
where: I OUT = maximum DC load current
LIR = ratio of peak-to-peak AC inductor current
to DC load current, typically 0.25
The peak inductor current at full load is 1.125 · I OUT if
the above equation is used; otherwise, the peak current
is calculated by:
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
decreases stability. Choose the capacitor values that
result in optimal performance.
I PEAK = I OUT +
V OUT × t OFF
2 × L
Setting the AC Loop Gain
The MAX1644 allows selection of a 1% or 2% AC load-
regulation error when the adjustable output voltage
Choose an inductor with a saturation current at least as
high as the peak inductor current. To minimize loss,
choose an inductor with a low DC resistance.
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:
mode is selected (Table 2). A 2% setting is automati-
cally selected in preset output voltage mode (FBSEL
connected to V CC or unconnected). A 2% load-regula-
tion error setting reduces output filter capacitor require-
ments, allowing the use of smaller and less expensive
capacitors. Selecting a 1% load-regulation error
reduces transient load errors, but requires larger capac-
itors.
V OUT ( IN ? V OUT
I RIPPLE = I LOAD
V
V IN
)
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1644EAE/GH9 | 功能描述:直流/直流开关转换器 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 |
| MAX1644EAE/GH9-T | 功能描述:直流/直流开关转换器 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 |
| MAX1644EAE+ | 功能描述:直流/直流开关转换器 2A Step-Dow w/Synch Rectification 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 |
| MAX1644EAE+T | 功能描述:直流/直流开关转换器 2A Step-Dow w/Synch Rectification 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 |
| MAX1644EAE+TG116 | 制造商:Maxim Integrated Products 功能描述:2A, LOW-VOLTAGE, STEP-DOWN REGULATOR WITH SYNCHRONOUS RECTIF - Tape and Reel |
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