NSC LM2765M6 Datasheet

LM2765
Switched Capacitor Voltage Converter

LM2765 Switched Capacitor Voltage Converter

March 2000

General Description

The LM2765 CMOS charge-pump voltage converter oper­ates 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 mAof output current.

The LM2765 operates at 50 kHz switching frequency to re­duce output resistance and voltage ripple. With an operating
current of only130 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 pack­age.

Basic Application Circuits

Voltage Doubler

Features

n Doubles Input Supply Voltage
n SOT23-6 Package
n 20Ω Typical Output Impedance
n 90% Typical Conversion Efficiency at 20 mA
n 0.1µA Typical Shutdown Current

Applications

n Cellular Phones
n Pagers
n PDAs
n Operational Amplifier Power Supplies
n Interface Power Supplies
n Handheld Instruments

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

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.

© 2000 National Semiconductor Corporation DS101281 www.national.com

Package

Marking

Supplied as

Pin Description

LM2765

Pin Name Function

1 V+ Power supply positive voltage input.
2 GND Power supply ground input.
3 CAP− Connect this pin to the negative terminal of the charge-pump

4 SD Shutdown control pin, tie this pin to ground in normal operation.
5V
6 CAP+ Connect this pin to the positive terminal of the charge-pump

OUT

capacitor.

Positive voltage output.

capacitor.

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Absolute Maximum Ratings (Note 2)

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 V+ to V

) 5.8V

OUT

SD (GND − 0.3V) to (V+ +

0.3V)

V

Continuous Output Current 40 mA

OUT

Output Short-Circuit Duration to GND (Note 3) 1 sec.
Continuous Power

Dissipation (T
T

(Note 4) 150˚C

JMax

= 25˚C)(Note 4)

A

600 mW

Operating Ratings

θJA(Note 4) 210˚C/W

Junction Temperature Range −40˚ to 100˚C
Ambient Temperature Range −40˚ to 85˚C
Storage Temperature Range −65˚C to 150˚C
Lead Temp. (Soldering, 10

seconds) 240˚C
ESD Rating (Note 5)

Human body model
Machine model

200V

2kV

Electrical Characteristics

Limits in standard typeface are for TJ= 25˚C, and limits in boldface type apply over the full operating temperature range. Un­less otherwise specified: V+ = 5V, C

Symbol Parameter Condition Min Typ Max Units

V+ Supply Voltage 1.8 5.5 V
I

Q

I

SD

V

SD

I

L

R

OUT

f

OSC

f

SW

P

EFF

V

OEFF

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
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
ambient temperature, and θ

Note 5: The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly
into each pin.

Note 6: In the test circuit, capacitors C
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

Supply Current No Load 130 450 µA
Shutdown Supply Current 0.1 0.5

Shutdown Pin Input Voltage Shutdown Mode 2.0

Output Current 2.5V ≤ VIN≤ 5.5V 20

Output Resistance (Note 7) IL=20mA 20 40 Ω
Oscillator Frequency (Note 8) 40 100 200 kHz
Switching Frequency (Note 8) 20 50 100 kHz
Power Efficiency IL= 20 mA to GND 92 %
Voltage Conversion Efficiency No Load 99.96 %

may be shorted to GND for one second without damage. However, shorting V

OUT

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

JA

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

1

= 3.3 µF. (Note 6)

1=C2

= 85˚C 0.2

T

A

Normal Operation 0.6

<

1.8V ≤ V

2.5V 10

IN

to V+ may damage the device and should be avoided. Also, for tem-

OUT

DMax

OSC

=(T

=2fSW.

JMax−TA

)/θJA, where T

is the maximum junction temperature, TAis the

JMax

mA

LM2765

µA

V

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