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| 型号： | MAX860IUA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/11页 |
| 文件大小： | 0K |
| 描述： | IC REG SWITCHD CAP DBL INV 8UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 切换式电容器（充电泵），倍增器，反相 |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | -1.5 V ~ -5.5 V，3 V ~ 11 V |
| 输入电压： | 1.5 V ~ 5.5 V |
| 频率 - 开关： | 6kHz，50kHz，130kHz |
| 电流 - 输出： | 50mA |
| 同步整流器： | 无 |
| 工作温度： | -25°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 |
MAX860/MAX861
50mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters
Flying Capacitor, C1
Increasing the size of the flying capacitor reduces the
output resistance.
Output Capacitor, C2
Increasing the size of the output capacitor reduces the
output ripple voltage. Decreasing its ESR reduces both
output resistance and ripple. Smaller capacitance val-
ues can be used if one of the higher switching frequen-
cies is selected, if less than the maximum rated output
current (50mA) is required, or if higher ripple can be
tolerated. The following equation for peak-to-peak rip-
ple applies to both the inverter and doubler circuits.
I OUT
V RIPPLE = ———————— + 2 x I OUT x ESR C2
2 x f S x C2
Bypass Capacitor
Bypass the incoming supply to reduce its AC impedance
and the impact of the MAX860/MAX861 ’s switching
noise. The recommended bypassing depends on the cir-
cuit configuration and where the load is connected.
When the inverter is loaded from OUT to GND or the
doubler is loaded from V DD to GND, current from the
supply switches between 2 x I OUT and zero. Therefore,
use a large bypass capacitor (e.g., equal to the value
of C1) if the supply has a high AC impedance.
When the inverter and doubler are loaded from V DD to
OUT, the circuit draws 2 x I OUT constantly, except for
short switching spikes. A 0.1μF bypass capacitor is
sufficient.
Cascading Devices
Two devices can be cascaded to produce an even
larger negative voltage, as shown in Figure 1. The
unloaded output voltage is nominally -2 x V IN , but this is
reduced slightly by the output resistance of the first
device multiplied by the quiescent current of the sec-
ond. The output resistance of the complete circuit is
approximately five times the output resistance of a sin-
gle MAX860/MAX861.
Three or more devices can be cascaded in this way,
but output resistance rises dramatically, and a better
solution is offered by inductive switching regulators
(such as the MAX755, MAX759, MAX764, or MAX774).
Connect LV as with a standard inverter circuit (see Pin
Description).
The maximum load current and startup current of nth
cascaded circuit must not exceed the maximum output
current capability of (n-1)th circuit to ensure proper
startup.
Paralleling Devices
Paralleling multiple MAX860s or MAX861s reduces the
output resistance. As illustrated in Figure 2, each
device requires its own pump capacitor (C1), but the
reservoir capacitor (C2) serves all devices. C2’s value
should be increased by a factor of n, where n is the
number of devices. Figure 2 shows the equation for cal-
culating output resistance. An alternative solution is to
use the MAX660 or MAX665, which are capable of sup-
plying up to 100mA of load current. Connect LV as with
a standard inverter circuit (see Pin Description).
Combined Doubler/Inverter
In the circuit of Figure 3, capacitors C1 and C2 form the
inverter, while C3 and C4 form the doubler. C1 and C3
are the pump capacitors; C2 and C4 are the reservoir
capacitors. Because both the inverter and doubler use
part of the charge-pump circuit, loading either output
causes both outputs to decline towards GND. Make
8
…
+V IN
8
8
R OUT OF SINGLE DEVICE
R OUT = NUMBER OF DEVICES
…
+V IN
8
C1
2
3
4
MAX860
MAX861
“1”
7
5
C1
2
3
4
…
C2
MAX860
MAX861
“n”
7
5
V OUT
C2
C1
2
3
4
MAX860
MAX861
“1”
7
5
C1
…
2
3
4
MAX860
MAX861
“n”
7
5
V OUT
V OUT = -nV IN
V OUT = -V IN
C2
Figure 1. Cascading MAX860s or MAX861s to Increase
Output Voltage
8
Figure 2. Paralleling MAX860s or MAX861s to Reduce Output
Resistance
Maxim Integrated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX860MJA | 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 |
| MAX860MSA/PR2 | 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 |
| MAX860MSA/PR2-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 |
| MAX8610ETD+ | 制造商:Maxim Integrated Products 功能描述: |
| MAX8610ETM+ | 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 |
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