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參數(shù)資料
| 型號： | MAX1852 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | SC70 Inverting Charge Pumps with Shutdown |
| 中文描述： | SC70封裝、反相電荷泵，帶有關(guān)斷 |
| 文件頁數(shù)： | 6/8頁 |
| 文件大小： | 217K |
| 代理商： | MAX1852 |
M
SC70 Inverting Charge Pumps
with Shutdown
6
_______________________________________________________________________________________
Input Bypass Capacitor (C3)
If necessary, bypass the incoming supply to reduce its
AC impedance and the impact of the MAX1852/
MAX1853s
’
switching noise. A bypass capacitor with a
value equal to that of C1 is recommended.
Voltage Inverter
The most common application for these devices is a
charge-pump voltage inverter (Figure 1). This applica-
tion requires only two external components
—
capacitors
C1 and C2
—
plus a bypass capacitor, if necessary.
Refer to the
Capacitor Selection
section for suggested
capacitor types.
Cascading Devices
Two devices can be cascaded to produce an even
larger negative voltage (Figure 4). The unloaded output
voltage is normally -2
V
IN
, but this is reduced slightly
by the output resistance of the first device multiplied by
the quiescent current of the second. When cascading
more than two devices, the output resistance rises sig-
nificantly. For applications requiring larger negative
voltages, see the MAX865 and MAX868 data sheets.
Paralleling Devices
Paralleling multiple MAX1852/MAX1853s reduces the
output resistance. Each device requires its own pump
capacitor (C1), but the reservoir capacitor (C2) serves
all devices (Figure 5). Increase C2
’
s value by a factor of
n
, where
n
is the number of parallel devices. Figure 5
shows the equation for calculating output resistance.
Combined Doubler/Inverter
In the circuit of Figure 6, 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 toward GND. Make sure
the sum of the currents drawn from the two outputs
does not exceed 30mA.
Heavy Load Connected to a
Positive Supply
Under heavy loads, where a higher supply is sourcing
current into OUT, the OUT supply must not be pulled
above ground. Applications that sink heavy current into
OUT require a Schottky diode (1N5817) between GND
and OUT, with the anode connected to OUT (Figure 7).
Layout and Grounding
Good layout is important, primarily for good noise per-
formance. To ensure good layout, mount all compo-
nents as close together as possible, keep traces short
to minimize parasitic inductance and capacitance, and
use a ground plane.
V
=
I
2(f
)C2
2 I
ESR
RIPPLE
OUT
OSC
OUT
C2
+
×
S1
IN
S2
S3
S4
C1
C2
V
OUT
= -(V
IN
)
Figure 2. Ideal Voltage Inverter
V+
C1
f
OSC
C2
R
L
V
OUT
Figure 3a. Switched-Capacitor Model
R
EQUIV
=
R
EQUIV
V
OUT
R
L
1
V+
f
OSC
C1
C2
Figure 3b. Equivalent Circuit
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相關(guān)代理商/技術(shù)參數(shù) |
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|---|---|
| MAX1852EXT | 制造商:Maxim Integrated Products 功能描述:SC70 50KHZ INVERTING CHARGE PUMP - Cut Tape Product |
| MAX1852EXT+ | 制造商:Maxim Integrated Products 功能描述:CHG PUMP INV -2.5V TO -5.5V 30MA 6PIN SC-70 - Rail/Tube |
| MAX1852EXT+T | 功能描述:電荷泵 Inverting w/Shutdown RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| MAX1852EXT-T | 功能描述:電荷泵 Inverting w/Shutdown RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| MAX1853EXT | 制造商:Maxim Integrated Products 功能描述:SC70 200KHZ INVERTING CHARGE PUMP - Rail/Tube 制造商:Rochester Electronics LLC 功能描述: |
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