参数资料
| 型号： | MAX1720EUT |
| 厂商： | ON Semiconductor |
| 文件页数： | 5/18页 |
| 文件大小： | 0K |
| 描述： | IC REG SWITCHD CAP INV ADJ 6TSOP |
| 产品变化通告： | LTB Notification 03/Jan/2008 |
| 标准包装： | 3,000 |
| 类型： | 切换式电容器（充电泵），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： | 12kHz |
| 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： | SC-74，SOT-457 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 6-TSOP |
| 其它名称： | MAX1720EUTOS |
MAX1720
?V out
Charge Pump Efficiency
The overall power conversion efficiency of the charge
+ 2
1
6
C
R L
pump is affected by four factors:
1. Losses from power consumed by the internal
OSC
oscillator, switch drive, etc. (which vary with input
V in
+
C 3
2
5
+
C 1
voltage, temperature and oscillator frequency).
2. I 2 R losses due to the on?resistance of the MOSFET
switches on?board the charge pump.
3
4
3. Charge pump capacitor losses due to Equivalent
Series Resistance (ESR).
4. Losses that occur during charge transfer from the
C 1 = C 2 = C 3 = 10 m F
Figure 14. Test Setup/Voltage Inverter
DETAILED OPERATING DESCRIPTION
commutation capacitor to the output capacitor when
a voltage difference between the two capacitors
exists.
Most of the conversion losses are due to factors 2, 3 and 4.
These losses are given by Equation 1.
LOSS(2,3,4)
The MAX1720 charge pump converter inverts the voltage
applied to the V in pin. Conversion consists of a two?phase
P
+ I out 2
R out ^ I out 2
operation (Figure 15). During the first phase, switches S 2 and
S 4 are open and S 1 and S 3 are closed. During this time, C 1
charges to the voltage on V in and load current is supplied from
C 2 . During the second phase, S 2 and S 4 are closed, and S 1 and
(f
1
OSC
)C1
) 8R
SWITCH
) 4ESR
C1
) ESR
C2
(eq. 1)
S 3 are open. This action connects C 1 across C 2 , restoring
charge to C 2 .
The 1/(f OSC )(C 1 ) term in Equation 1 is the effective output
resistance of an ideal switched capacitor circuit (Figures 16
V in
S1
S2
and 17).
The losses due to charge transfer above are also shown in
Equation 2. The output voltage ripple is given by Equation 3.
C 1
PLOSS + [ 0.5C 1 (Vin 2 * Vout 2 )
C 2
) 0.5C2 (VRIPPLE 2 * 2VoutVRIPPLE)]
fOSC
(eq. 2)
S3
S4
?V out
V
RIPPLE
+
(f
Iout
OSC )(C 2)
) 2(I out)(ESR
C2
)
(eq. 3)
From Osc
f
Figure 15. Ideal Switched Capacitor Charge Pump
V in
V out
APPLICATIONS INFORMATION
C 1
C 2
R L
Output Voltage Considerations
The MAX1720 performs voltage conversion but does not
provide regulation. The output voltage will drop in a linear
manner with respect to load current. The value of this
equivalent output resistance is approximately 26 W nominal
at 25 ° C with V in = 5.0 V. V out is approximately ?5.0 V at light
Figure 16. Ideal Switched Capacitor Model
R EQUIV
loads, and drops according to the equation below:
V in
V out
VDROP + Iout Rout
Vout + * (Vin * VDROP)
R
EQUIV
+
f
1
C1
C 2
R L
Figure 17. Equivalent Output Resistance
http://onsemi.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1720EUT+ | 制造商:Maxim Integrated Products 功能描述:CHG PUMP INV -1.25V TO -5.5V 25MA 6PIN SOT-23 - Rail/Tube |
| MAX1720EUT+T | 功能描述:电荷泵 Switched-Cap Voltage Inverter w/Shutdown 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 |
| MAX1720EUTG | 功能描述:电荷泵 Switched Cap Voltage Inverter w/Shutdown 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 |
| MAX1720EUT-T | 功能描述:电荷泵 Switched-Cap Voltage Inverter w/Shutdown 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 |
| MAX1721EUT | 制造商:Maxim Integrated Products 功能描述:VOLTAGE INVERTER - Rail/Tube |
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