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参数资料
| 型号： | MAX684EUA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 6/12页 |
| 文件大小： | 0K |
| 描述： | IC REG SWITCHED CAP 5V 8UMAX |
| 标准包装： | 2,500 |
| 类型： | 切换式电容器（充电泵） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 5V |
| 输入电压： | 2.7 V ~ 5.5 V |
| 频率 - 开关： | 200kHz，1MHz |
| 电流 - 输出： | 50mA |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-uMAX |
3.3V-Input to Regulated 5V-Output
Charge Pumps
Detailed Description
The MAX682/MAX683/MAX684 charge pumps provide
IN
S2
OUT
a regulated 5V output from a 2.7V to 5.5V input. They
deliver a maximum of 250mA, 100mA, or 50mA load
current, respectively. Designed specifically for com-
pact applications, a complete regulator circuit requires
only three small external capacitors and one resistor.
An externally adjustable switching frequency and inno-
vative control scheme allow the circuit to be optimized
for efficiency, size, or output noise. The devices also
contain a shutdown feature.
The MAX682/MAX683/MAX684 consist of an error
amplifier, a 1.23V bandgap reference, an internal resis-
tive feedback network, an oscillator, high-current MOS-
C IN
S1
C X
OSC
C OUT
FET switches, and shutdown and control logic (Figure
1). Figure 2 shows an idealized unregulated charge-
pump voltage doubler. The oscillator runs at a 50%
duty cycle. During one half of the period, the transfer
Figure 2. Unregulated Voltage Doubler
capacitor (C X ) charges to the input voltage. During the
IN
S2
OUT
other half, the doubler stacks the voltage across C X
and the input voltage, and transfers the sum of the two
voltages to the output filter capacitor (C OUT ). Rather
than simply doubling the input voltage, the
MAX682/MAX683/MAX684 provide a regulated fixed
S1
C X
output voltage (5V) using either skip mode or constant-
frequency mode. Skip mode and constant-frequency
mode are externally selected via the SKIP input pin.
C IN
EN
OSCILLATOR
OUT
IN
Figure 3. Skip-Mode Regulation
Skip Mode
SKIP
CONTROL
LOGIC
1.23V
In skip mode ( SKIP = low), the error amplifier disables
switching when it detects an output higher than 5V. The
device then skips switching cycles until the output volt-
age drops. Then the error amplifier reactivates the
SHDN
CXP
oscillator. Figure 3 illustrates the regulation scheme.
This regulation method minimizes operating current
SHDN
EN
OSC
SWITCHES
CXN
because the device does not switch continuously. SKIP
is a logic input and should not remain floating.
Constant-Frequency Mode
When SKIP is high, the charge pump runs continuously
Figure 1. Functional Block Diagram
PGND
at the selected frequency. Figure 4 shows a block dia-
gram of the device in constant-frequency mode. The
error amplifier controls the charge on C X by driving the
gate of the N-channel FET. When the output voltage
falls, the gate drive increases, resulting in a larger volt-
age across C X . This regulation scheme minimizes out-
put ripple. Since the device switches continuously, the
6
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| MAX6850AEE | 功能描述:VFD驱动器 RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube |
| MAX6850AEE+T | 功能描述:VFD驱动器 RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube |
| MAX6850AEE-T | 功能描述:VFD驱动器 RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube |
| MAX6851AEE | 功能描述:VFD驱动器 RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube |
| MAX6851AEE+T | 功能描述:VFD驱动器 RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube |
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