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 A (operating efficiency greater than 90%
with most loads) and 0.1A 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
Typical Output Impedance
n
90% Typical Conversion Efficiency at 20 mA
n
0.1A Typical Shutdown Current
Applications
n
Cellular Phones
n
Pagers
n
PDAs
n
Operational Amplifier Power Supplies
n
Interface Power Supplies
n
Handheld Instruments
Basic Application Circuits
Connection Diagram
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.
Voltage Doubler
DS101281-1
6-Lead SOT (M6)
DS101281-13
Top View With Package Marking
DS101281-22
Actual Size
March 2000
LM2765
Switched
Capacitor
V
oltage
Converter
2000 National Semiconductor Corporation
DS101281
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.
Supply Voltage (V+ to GND, or V+ to V
OUT
)
5.8V
SD
(GND - 0.3V) to (V+ +
0.3V)
V
OUT
Continuous Output Current
40 mA
Output Short-Circuit Duration to GND (Note 3)
1 sec.
Continuous Power
Dissipation (T
A
= 25C)(Note 4)
600 mW
T
JMax
(Note 4)
150C
Operating Ratings
JA
(Note 4)
210C/W
Junction Temperature Range
-40 to 100C
Ambient Temperature Range
-40 to 85C
Storage Temperature Range
-65C to 150C
Lead Temp. (Soldering, 10
seconds)
240C
ESD Rating (Note 5)
Human body model
Machine model
2kV
200V
Electrical Characteristics
Limits in standard typeface are for T
J
= 25C, and limits in boldface type apply over the full operating temperature range. Un-
less otherwise specified: V+ = 5V, C
1
= C
2
= 3.3 F. (Note 6)
Symbol
Parameter
Condition
Min
Typ
Max
Units
V+
Supply Voltage
1.8
5.5
V
I
Q
Supply Current
No Load
130
450
A
I
SD
Shutdown Supply Current
0.1
0.5
A
T
A
= 85C
0.2
V
SD
Shutdown Pin Input Voltage
Shutdown Mode
2.0
V
Normal Operation
0.6
I
L
Output Current
2.5V
V
IN
5.5V
20
mA
1.8V
V
IN
<
2.5V
10
R
OUT
Output Resistance (Note 7)
I
L
= 20 mA
20
40
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 85C, 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
)/
JA
, where T
JMax
is the maximum junction temperature, T
A
is the
ambient temperature, and
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 F, 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
.
LM2765
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