Connection Diagram

Ordering Information

Order Number

Package

Number

Package

Marking

Supplied as

LM2664M6

MA06A

SO3A (Note 9)

Tape and Reel (1000 units/rail)

LM2664M6X

MA06A

SO3A (Note 9)

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.

4SD

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 S

age V+. During this time interval, switches S

open. In the second time interval, S

same time, S

number of cycles, the voltage across C

V+. Since the anode of C

at the cathode of C

rent. The output voltage drop when a load is added is deter-

mined by the parasitic resistance (R

switches and the ESR of the capacitors) and the charge

transfer loss between capacitors. Details will be discussed in

the following application information section.

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 R

function of the ON resistance of the internal MOSFET

switches, the oscillator frequency, the capacitance and ESR

of C

charging C

6-Lead Small Outline Package (M6)

DS100031-4

Top View With Package Marking

DS100031-22

Actual Size

DS100031-5

FIGURE 2. Voltage Inverting Principle

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