|
|
PDF LM2664 Data sheet ( Hoja de datos )
| Número de pieza | LM2664 | |
| Descripción | Switched Capacitor Voltage Converter | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LM2664 (archivo pdf) en la parte inferior de esta página. Total 9 Páginas | ||
|
No Preview Available !
November 1999
LM2664
Switched Capacitor Voltage Converter
General Description
The LM2664 CMOS charge-pump voltage converter inverts
a positive voltage in the range of +1.8V to +5.5V to the cor-
responding negative voltage of −1.8V to −5.5V. The LM2664
uses two low cost capacitors to provide up to 40 mA of out-
put current.
The LM2664 operates at 160 kHz oscillator frequency to re-
duce output resistance and voltage ripple. With an operating
current of only 220 µA (operating efficiency greater than 91%
with most loads) and 1 µA typical shutdown current, the
LM2664 provides ideal performance for battery powered
systems. The device is in SOT-23-6 package.
Features
n Inverts Input Supply Voltage
n SOT23-6 Package
n 12Ω Typical Output Impedance
n 91% Typical Conversion Efficiency at 40 mA
n 1µA Typical Shutdown Current
Applications
n Cellular Phones
n Pagers
n PDAs
n Operational Amplifier Power Suppliers
n Interface Power Suppliers
n Handheld Instruments
Basic Application Circuits
Voltage Inverter
+5V to −10V Converter
DS100031-1
© 1999 National Semiconductor Corporation DS100031
DS100031-25
www.national.com
1 page  
Connection Diagram
6-Lead Small Outline Package (M6)
DS100031-22
Actual Size
DS100031-4
Top View With Package Marking
Ordering Information
Order Number
LM2664M6
LM2664M6X
Package
Number
MA06A
MA06A
Package
Marking
SO3A (Note 9)
SO3A (Note 9)
Supplied as
Tape and Reel (1000 units/rail)
Tape and Reel (3000 units/rail)
Note 9: The first letter ″S″ identifies the part as a switched capacitor converter. The next two numbers are the device number. The fourth letter ″A″ indicates the
grade. Only one grade is available. Larger quantity reels are available upon request.
Pin Description
Pin Name
Function
1
GND
Power supply ground input.
2
OUT
Negative voltage output.
3
CAP−
Connect this pin to the negative terminal of the charge-pump capacitor.
4 SD Shutdown control pin, tie this pin to V+ in normal operation, and to GND for shutdown.
5 V+ Power supply positive voltage input.
6
CAP+
Connect this pin to the positive terminal of the charge-pump capacitor.
Circuit Description
The LM2664 contains four large CMOS switches which are
switched in a sequence to invert the input supply voltage.
Energy transfer and storage are provided by external capaci-
tors. Figure 2 illustrates the voltage conversion scheme.
When
S1
and
S3
are
closed,
C
1
charges
to
the
supply
volt-
age V+. During this time interval, switches S2 and S4 are
open. In the second time interval, S1 and S3 are open; at the
same time, S2 and S4 are closed, C1 is charging C2. After a
number of cycles, the voltage across C2 will be pumped to
V+. Since the anode of C2 is connected to ground, the output
at the cathode of C2 equals −(V+) when there is no load cur-
rent. The output voltage drop when a load is added is deter-
mined by the parasitic resistance (Rds(on) of the MOSFET
switches and the ESR of the capacitors) and the charge
transfer loss between capacitors. Details will be discussed in
the following application information section.
FIGURE 2. Voltage Inverting Principle
DS100031-5
Application Information
Simple Negative Voltage Converter
The main application of LM2664 is to generate a negative
supply voltage. The voltage inverter circuit uses only two ex-
ternal capacitors as shown in the Basic Application Circuits.
The range of the input supply voltage is 1.8V to 5.5V.
The output characteristics of this circuit can be approximated
by an ideal voltage source in series with a resistance. The
voltage source equals −(V+). The output resistance Rout is a
function of the ON resistance of the internal MOSFET
switches, the oscillator frequency, the capacitance and ESR
of C1 and C2. Since the switching current charging and dis-
charging C1 is approximately twice as the output current, the
5 www.national.com
5 Page | ||
| Páginas | Total 9 Páginas | |
| PDF Descargar | [ Datasheet LM2664.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LM2660 | Switched Capacitor Voltage Converter | National Semiconductor |
| LM2660 | LM2660 Switched Capacitor Voltage Converter (Rev. E) |  Texas Instruments |
| LM2660M | Switched Capacitor Voltage Converter | National Semiconductor |
| LM2660MM | Switched Capacitor Voltage Converter | National Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |