156869 Datasheet, PDF (5/9 Pages) Texas Instruments – Switched Capacitor Voltage Converter

Connection Diagrams
6-Lead Small Outline Package (M6)
10003122
Actual Size
10003104
Top View With Package Marking
Ordering Information
Order Number
LM2664M6
LM2664M6X
Package Number
MA06A
MA06A
Package Marking
Supplied as
SO3A (Note 11) Tape and Reel (1000 units/rail)
SO3A (Note 11) Tape and Reel (3000 units/rail)
Note 11: 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 Descriptions
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, C₁ charges to the supply
voltage 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
current. The output voltage drop when a load is added is
determined by the parasitic resistance (R_ds(on) of the MOS-
FET 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
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