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参数资料
| 型号： | MAX1649CSA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/12页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 8-SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 控制器 |
| 输出数： | 1 |
| 频率 - 最大： | 300kHz |
| 占空比： | 96.5% |
| 电源电压： | 3 V ~ 16 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： | 0°C ~ 70°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
5V/3.3V or Adjustable, High-Efficiency,
Low-Dropout, Step-Down DC-DC Controllers
V IN
C4
C1
V+
5
0.1 μ F
100 μ F
1.5A
1A
3
MAX1649
MAX1651
SHDN
CS
EXT
R1
0.05 Ω
6
7
P1
Si9430
L1
47 μ H
OUTPUT
@ 1.5A
0A
4
REF
GND
OUT
FB
1
2
R2
2 μ s/div
V+ = 10V, I LOAD = 1.3A
CIRCUIT OF FIGURE 1, R1 = 75m Ω
C3
0.1 μ F
R2 = R3
(
V OUT
V REF
–1
8
)
D1
1N5820
C2
330 μ F
R3
150k
V REF = 1.5V
(
)
Figure 3. MAX1649 Continuous-Conduction Mode, Heavy
Load-Current Waveform (500mA/div)
Modes of Operation
When delivering high output currents, the MAX1649/
MAX1651 operate in continuous-conduction mode. In
this mode, current always flows in the inductor, and
the control circuit adjusts the switch duty cycle to main-
tain regulation without exceeding the switch current
capability (Figure 3). This provides excellent load-tran-
sient response and high efficiency.
In discontinuous-conduction mode, current through the
inductor starts at zero, rises to a peak value, then
ramps down to zero. Although efficiency is still excel-
lent, the output ripple increases slightly, and the switch
waveform exhibits ringing (at the inductor's self-reso-
nant frequency). This ringing is to be expected and
poses no operational problems.
Dropout
The MAX1649/MAX1651 are in dropout when the input
voltage (V+) is low enough that the output drops below
the minimum output voltage specification (see
Electrical Characteristics ). The dropout voltage is the
difference between the input and output voltage when
dropout occurs. See the Typical Operating
Characteristics for the Dropout Voltage vs. Load
Current and Dropout Voltage vs. Temperature graphs.
Figure 4. Adjustable-Output Operation
__________________Design Procedure
Setting the Output Voltage
The MAX1649/MAX1651 are preset for 5V and 3.3V out-
put voltages, respectively; tie FB to GND for fixed-output
operation. They may also be adjusted from 1.5V (the
reference voltage) to the input voltage, using external
resistors R2 and R3 configured as shown in Figure 4. For
adjustable-output operation, 150k Ω is recommended for
resistor R3—high enough to avoid wasting energy, yet
low enough to avoid RC delays caused by parasitic
capacitance at FB. R2 is given by:
V OUT
R2 = R3 x ——— -1
V REF
where V REF = 1.5V.
When using external resistors, it does no harm to con-
nect OUT and the output together, or to leave OUT
unconnected.
Current-Sense Resistor Selection
The current-sense resistor limits the peak switch cur-
rent to 110mV/R SENSE , where R SENSE is the value of
the current-sense resistor, and 110mV is the current-
limit trip level (see Electrical Characteristics ).
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1649EPA | 功能描述:DC/DC 开关控制器 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 |
| MAX1649EPA+ | 功能描述:DC/DC 开关控制器 3V or Adjustable High-Efficiency Low-Dropout Step-Down DC-DC 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 |
| MAX1649ESA | 功能描述:DC/DC 开关控制器 5/3.3/Adj Low-Drop Step-Down 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 |
| MAX1649ESA+ | 功能描述:DC/DC 开关控制器 5/3.3/Adj Low-Drop Step-Down 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 |
| MAX1649ESA+T | 功能描述:DC/DC 开关控制器 5/3.3/Adj Low-Drop Step-Down 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 |
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