lm2765.pdf

March 2000

LM2765

Switched Capacitor Voltage Converter

General Description

The LM2765 CMOS charge-pump voltage converter oper-

ates as a voltage doubler for an input voltage in the range of

+1.8V to +5.5V. Two low cost capacitors and a diode are

used in this circuit to provide up to 20 mA of output current.

The LM2765 operates at 50 kHz switching frequency to re-

duce output resistance and voltage ripple. With an operating

current of only 130 µA (operating efficiency greater than 90%

with most loads) and 0.1µA typical shutdown current, the

LM2765 provides ideal performance for battery powered

systems. The device is manufactured in a SOT-23-6 pack-

age.

Features

n Doubles Input Supply Voltage

n SOT23-6 Package

n 20

Applications

n Cellular Phones

n Pagers

n PDAs

n Operational Amplifier Power Supplies

n Interface Power Supplies

n Handheld Instruments

Basic Application Circuits

Voltage Doubler

DS101281-1

Connection Diagram

6-Lead SOT (M6)

DS101281-22

Actual Size

DS101281-13

Top View With Package Marking

Ordering Information

Order Number

Package

Number

Package

Marking

Supplied as

LM2765M6

MA06A

S15B (Note 1)

Tape and Reel (1000 units/reel)

LM2765M6X

MA06A

S15B (Note 1)

Tape and Reel (3000 units/reel)

Note 1: The small physical size of the SOT-23 package does not allow for the full part number marking. Devices will be marked with the designation shown in

the column Package Marking.

DS101281

www.national.com

Typical Output Impedance

n 90% Typical Conversion Efficiency at 20 mA

n 0.1µA Typical Shutdown Current

Pin Description

Name

Function

V+

Power supply positive voltage input.

GND

Power supply ground input.

CAP−

Connect this pin to the negative terminal of the charge-pump

capacitor.

Shutdown control pin, tie this pin to ground in normal operation.

V OUT

Positive voltage output.

CAP+

Connect this pin to the positive terminal of the charge-pump

capacitor.

www.national.com

Absolute Maximum Ratings (Note 2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

Operating Ratings

q JA (Note 4)

210˚C/W

Supply Voltage (V+ to GND, or V+ to V OUT )

5.8V

Junction Temperature Range

−40˚ to 100˚C

(GND − 0.3V) to (V+ +

0.3V)

Ambient Temperature Range

−40˚ to 85˚C

Storage Temperature Range

−65˚C to 150˚C

V OUT Continuous Output Current

40 mA

Lead Temp. (Soldering, 10

seconds)

Output Short-Circuit Duration to GND (Note 3)

1 sec.

240˚C

Continuous Power

Dissipation (T A = 25˚C)(Note 4)

600 mW

ESD Rating (Note 5)

Human body model

Machine model

2kV

200V

T JMax (Note 4)

150˚C

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 6)

Symbol

Parameter

Condition

Min

Typ

Max

Units

V+

Supply Voltage

1.8

5.5

I Q

Supply Current

No Load

130

450

µA

I SD

Shutdown Supply Current

0.1

0.5

µA

T A = 85˚C

0.2

V SD

Shutdown Pin Input Voltage

Shutdown Mode

2.0

Normal Operation

0.6

I L

Output Current

2.5V

V IN

5.5V

1.8V

V IN < 2.5V

f OSC Oscillator Frequency (Note 8) 40 100 200 kHz

f SW Switching Frequency (Note 8) 20 50 100 kHz

P EFF Power Efficiency I L = 20 mA to GND 92 %

V OEFF Voltage Conversion Efficiency No Load 99.96 %

Note 2: 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 3: V OUT may be shorted to GND for one second without damage. However, shorting V OUT to V+ may damage the device and should be avoided. Also, for tem-

peratures above 85˚C, OUT must not be shorted to GND or V+, or device may be damaged.

Note 4: The maximum allowable power dissipation is calculated by using P DMax =(T JMax −T A )/

Output Resistance (Note 7)

I L =20mA

q JA , where T JMax is the maximum junction temperature, T A is the

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

Note 5: The human body model is a 100pF capacitor discharged through a 1.5k

resistor into each pin. The machine model is a 200pF capacitor discharged directly

into each pin.

Note 6: In the test circuit, capacitors C 1 and C 2 are 3.3 µF, 0.3

maximum ESR capacitors. Capacitors with higher ESR will increase output resistance, reduce output

voltage and efficiency.

Note 7: Specified output resistance includes internal switch resistance and capacitor ESR. See the details in the application information for positive voltage doubler.

Note 8: The output switches operate at one half of the oscillator frequency, f OSC =2f SW .

www.national.com

R OUT

ambient temperature, and

Test Circuit

DS101281-3

FIGURE 1. LM2765 Test Circuit

Typical Performance Characteristics (Circuit of Figure 1, V IN =5V,T A = 25˚C unless otherwise

specified)

Supply Current vs

Supply Voltage

Output Resistance vs

Capacitance

DS101281-4

DS101281-5

Output Resistance vs

Supply Voltage

Output Resistance vs

Temperature

DS101281-6

DS101281-7

www.national.com

Typical Performance Characteristics (Circuit of Figure 1, V IN = 5V, T A = 25˚C unless otherwise

specified) (Continued)

Output Voltage vs

Load Current

Efficiency vs

Load Current

DS101281-9

DS101281-8

Switching Frequency vs

Supply Voltage

Switching Frequency vs

Temperature

DS101281-10

DS101281-11

Output Ripple vs

Load Current

DS101281-12

www.national.com

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: