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参数资料
| 型号： | MAX1686HEUA+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 6/8页 |
| 文件大小： | 0K |
| 描述： | IC CHARGE PUMP SIM CARD 8UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| 应用： | 充电泵，SIM 卡 |
| 输入电压： | 2.7 V ~ 4.2 V |
| 输出数： | 1 |
| 输出电压： | 5V |
| 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） |
| 供应商设备封装： | 8-uMAX |
| 包装： | 管件 |
3V to 5V Regulating
Charge Pumps for SIM Cards
1μA. Other features include soft-start, undervoltage
lockout, and short-circuit protection.
Charge-Pump Control
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 capac-
itor (C X ) charges to the input voltage. During the 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 ). The MAX1686 uses
Skip Mode control to regulate its output voltage and to
achieve good efficiency over a large output current
range. When the comparator detects that the output
voltage is too low, the 1MHz oscillator is enabled and
C X is switched. When the output voltage is above regu-
lation, the oscillator is disabled and C X is connected at
the input.
Soft-Start
In the 5V mode (3/ 5 = GND), the start-up current is lim-
ited by the soft-start control to typically 200mA, inde-
pendent of the load. Until the output voltage reaches
V IN / 2, the input is connected to the output through a
50 ? series P-channel MOSFET and the charge pump
is disabled. For V IN / 2 < V OUT < 4.75V (5.00V for
MAX1686H) and for a maximum of 2ms the charge
pump is active, but R ON of the switch S2 is limited to
50 ? . This limits typical current surges associated with
charge pumps at start-up. When soft-start is complete,
V OUT > 4.75V (5.00V for MAX1686H) or 2ms (whichever
occurs first), switch S2’s on-resistance is decreased to
minimize losses.
C X
In 3V mode (3/ 5 = IN), the start-up current is limited by
the 50 ? series P-channel MOSFET connected between
IN and OUT until the output voltage reaches V IN / 2. For
V OUT > V IN / 2, R ON is reduced to 2.5 ? .
With a 500 ? load the device turns on in less than 1.5ms
(see Typical Operating Characteristics for graphs of
start-up waveforms).
Shutdown Mode
Driving SHDN low places the device in shutdown mode,
which disables the oscillator, the control logic, and the
reference. Placing the device in shutdown mode
reduces the no-load supply current to less than 1μA; the
output is actively discharged through the internal N-
channel FET and disconnected from the input. In normal
operation, SHDN is driven high or connected to IN.
Applications Information
Capacitor Selection
The MAX1686 requires only three external capacitors.
The capacitor values are closely linked to the output
current capability, noise, and switching frequency. The
1MHz oscillator frequency minimizes capacitor size
compared to lower-frequency charge pumps.
Generally, the transfer capacitor (C X ) will be the
smallest, the input capacitor (C IN ) will be twice the size
of C X , and the output capacitor (C OUT ) can be from 10
to 50 times C X . The suggested capacitor values are
C IN = 0.1μF, C X = 0.047μF, and C OUT = 2.2μF as
shown in Figure 3. For input voltages as low as 2.7V,
the following values are recommended: C IN = 0.47μF,
C X = 0.22μF, and C OUT = 10μF. Table 1 lists the perfor-
C X
0.047 μ F
CXN
CXP
IN
C IN
S1
S2
OUT
C OUT
INPUT
2.85V TO 4.2V
C IN
0.1 μ F
3
2
6 7
CXN CXP
IN
MAX1686
SHDN
OUT
8
OUTPUT
V IN OR 4.75V AT 20mA
C OUT
2.2 μ F
(CERAMIC)
OSC
3V
5V
1
3/5
GND
GND
4
PGND
5
Figure 2. Unregulated Voltage Doubler
Figure 3. Standard Application Circuit
6
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| MAX1686HEUA+ | 功能描述:电荷泵 3-5V Regulating Chrg Pump For SIM Cards RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| MAX1686HEUA+T | 功能描述:电荷泵 3-5V Regulating Chrg Pump For SIM Cards RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| MAX1686HEUA-T | 功能描述:电荷泵 3-5V Regulating Chrg Pump For SIM Cards RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| MAX1687ESA | 功能描述:直流/直流开关转换器 StepUp w/Prec Adapt Crnt Limit for GSM 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 |
| MAX1687ESA+ | 功能描述:直流/直流开关转换器 StepUp w/Prec Adapt Crnt Limit for GSM 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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