NSC LM2664MDC, LM2664M6 Datasheet

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 cor­responding negative voltage of −1.8V to −5.5V.The LM2664
uses two low cost capacitors to provide up to 40 mA of out­put current.

The LM2664 operates at 160 kHz oscillator frequency to re­duce 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

DS100031-1

+5V to −10V Converter

DS100031-25

November 1999

LM2664 Switched Capacitor Voltage Converter

© 1999 National Semiconductor Corporation DS100031 www.national.com

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage (V+ to GND, or GND to OUT) 5.8V
SD (GND − 0.3V) to (V+ +

0.3V)
V+ and OUT Continuous Output Current 50 mA
Output Short-Circuit Duration to GND (Note 2) 1 sec.

Continuous Power
Dissipation (T

A

=

25˚C)(Note 3)

600 mW

T

JMax

(Note 3) 150˚C

θ

JA

(Note 3) 210˚C/W

Operating Junction
Temperature Range

−40˚ to 85˚C

Storage Temperature Range −65˚C to +150˚C
Lead Temp. (Soldering, 10 seconds) 300˚C
ESD Rating 2kV

Electrical Characteristics

Limits in standard typeface are for T

J

=

25˚C, and limits in boldface type apply over the full operating temperature range. Un-

less otherwise specified: V+=5V, C

1

=

C

2

=

3.3 µF. (Note 4)

Symbol Parameter Condition Min Typ Max Units

V+ Supply Voltage 1.8 5.5 V
I

Q

Supply Current No Load 220 500 µA

I

SD

Shutdown Supply Current 1 µA

V

SD

Shutdown Pin Input Voltage Normal Operation 2.0

(Note 5)

V

Shutdown Mode 0.8

(Note 6)

I

L

Output Current 40 mA

R

SW

Sum of the R

ds(on)

of the four

internal MOSFET switches

I

L

=

40 mA 4 8

Ω

R

OUT

Output Resistance (Note 7) I

L

=

40 mA 12 25 Ω

f

OSC

Oscillator Frequency (Note 8) 80 160 kHz

f

SW

Switching Frequency (Note 8) 40 80 kHz

P

EFF

Power Efficiency RL(1.0k) between GND and

OUT

90 94

%

I

L

=

40 mA to GND 91

V

OEFF

Voltage Conversion Efficiency No Load 99 99.96

%

Note 1: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device
beyond its rated operating conditions.

Note 2: OUT may be shorted to GND for one second without damage. However,shorting OUT to V+ may damage the device and should be avoided. Also, for tem­peratures above 85˚C, OUT must not be shorted to GND or V+, or device may be damaged.

Note 3: The maximum allowable power dissipation is calculated by using P

DMax

=

(T

JMax−TA

)/θJA, where T

JMax

is the maximum junction temperature, TAis the

ambient temperature, and θ

JA

is the junction-to-ambient thermal resistance of the specified package.

Note 4: In the test circuit, capacitors C

1

and C2are 3.3 µF,0.3Ωmaximum ESR capacitors. Capacitors with higher ESR will increase output resistance, reduce output

voltage and efficiency.

Note 5: The minimum input high for the shutdown pin equals 40%of V+.
Note 6: The maximum input low for the shutdown pin equals 20%of V+.
Note 7: Specified output resistance includes internal switch resistance and capacitor ESR. See the details in the application information for simple negative voltage

converter.
Note 8: The output switches operate at one half of the oscillator frequency, f

OSC

=

2f

SW

.

LM2664

www.national.com 2

Test Circuit

Typical Performance Characteristics

(Circuit of Figure 1, V+=5V unless otherwise specified)

DS100031-3

*

C1and C2are 3.3 µF, SC series OS-CON capacitors.

FIGURE 1. LM2664 Test Circuit

Supply Current vs
Supply Voltage

DS100031-21

Supply Current vs
Temperature

DS100031-13

Output Source
Resistance vs Supply
Voltage

DS100031-14

Output Source
Resistance vs
Temperature

DS100031-15

LM2664

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