D ts e t
aa h e
R c e t r lc r nc
o h se Ee to is
Ma u a t r dCo o e t
n fc u e
mp n n s
R c e tr b a d d c mp n ns ae
o h se rn e
o oet r
ma ua trd u ig ete dewaes
n fcue sn i r i/ fr
h
p rh s d f m te oiia s p l r
uc a e r
o h r n l u pi s
g
e
o R c e tr waes rce td f m
r o h se
fr e rae r
o
te oiia I. Al rce t n ae
h
r nl P
g
l e rai s r
o
d n wi tea p o a o teOC
o e t h p rv l f h
h
M.
P r aetse u igoiia fcoy
at r e td sn r n la tr
s
g
ts p o rmso R c e tr e eo e
e t rga
r o h se d v lp d
ts s lt n t g aa te p o u t
e t oui s o u rne
o
rd c
me t o e c e teOC d t s e t
es r x e d h
M aa h e.
Qu l yOv riw
ai
t
e ve
• IO- 0 1
S 90
•A 92 cr ct n
S 1 0 et ai
i
o
• Qu l e Ma ua trr Ls (
ai d
n fcues it QML MI- R -
) LP F
385
53
•C a sQ Mitr
ls
lay
i
•C a sVS a eL v l
ls
p c ee
• Qu l e S p l r Ls o D sr uos( L )
ai d u pi s it f it b tr QS D
e
i
•R c e trsacic l u pir oD A a d
o h se i
r ia s p l t L n
t
e
me t aln u t a dD A sa d r s
es lid sr n L tn ad .
y
R c e tr lcrnc , L i c mmi e t
o h se Ee t is L C s o
o
tdo
t
s p ligp o u t ta s t f c so r x e t-
u pyn rd cs h t ai y u tme e p ca
s
t n fr u lya daee u loto eoiial
i s o q ai n r q a t h s r n l
o
t
g
y
s p l db id sr ma ua trr.
u pi
e yn ut
y n fcues
T eoiia ma ua trr d ts e t c o a yn ti d c me t e e t tep r r n e
h r n l n fcue’ aa h e a c mp n ig hs o u n r cs h ef ma c
g
s
o
a ds e ic t n o teR c e tr n fcue v rino ti d vc . o h se Ee t n
n p c ai s f h o h se ma ua trd eso f hs e ie R c e tr lcr -
o
o
isg aa te tep r r n eo i s mio d co p o u t t teoiia OE s e ic -
c u rne s h ef ma c ft e c n u tr rd cs o h r n l M p c a
o
s
g
t n .T pc lv le aefr eee c p r o e o l. eti mii m o ma i m rt g
i s ‘y ia’ au s r o rfrn e up s s ny C r n nmu
o
a
r xmu ai s
n
ma b b s do p o u t h rceiain d sg , i lt n o s mpetsig
y e a e n rd c c aa tr t , e in smuai , r a l e t .
z o
o
n
© 2 1 R cetr l t n s LC Al i t R sre 0 1 2 1
0 3 ohs E cr i , L . lRg s eevd 7 1 0 3
e e oc
h
T l r m r, l s v iw wrcl . m
o e n oe p ae it w . e c o
a
e
s
o ec
LM2660/LM2661 Switched Capacitor Voltage Converter
September 1999
LM2660/LM2661
Switched Capacitor Voltage Converter
General Description
The LM2660/LM2661 CMOS charge-pump voltage con-
verter inverts a positive voltage in the range of 1.5V to 5.5V
to the corresponding negative voltage. The LM2660/LM2661
uses two low cost capacitors to provide 100 mA of output
current without the cost, size, and EMI related to inductor
based converters. With an operating current of only 120 µA
and operating efficiency greater than 90% at most loads, the
LM2660/LM2661 provides ideal performance for battery
powered systems. The LM2660/LM2661 may also be used
as a positive voltage doubler.
The oscillator frequency can be lowered by adding an exter-
nal capacitor to the OSC pin. Also, the OSC pin may be used
to drive the LM2660/LM2661 with an external clock. For
LM2660, a frequency control (FC) pin selects the oscillator
frequency of 10 kHz or 80 kHz. For LM2661, an external
shutdown (SD) pin replaces the FC pin. The SD pin can be
used to disable the device and reduce the quiescent current
to 0.5 µA. The oscillator frequency for the LM2661 is 80 kHz.
Features
n
n
n
n
n
n
Inverts or doubles input supply voltage
Narrow SO-8 and Mini SO-8 Package
6.5Ω typical output resistance
88% typical conversion efficiency at 100 mA
(LM2660) selectable oscillator frequency: 10 kHz/80 kHz
(LM2661) low current shutdown mode
Applications
n
n
n
n
n
n
Laptop computers
Cellular phones
Medical instruments
Operational amplifier power supplies
Interface power supplies
Handheld instruments
Basic Application Circuits
Voltage Inverter
Positive Voltage Doubler
01291103
01291104
Splitting V
IN
in Half
01291126
© 2004 National Semiconductor Corporation
DS012911
www.national.com
LM2660/LM2661
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)
LV
FC, OSC
6V
M
Power Dissipation
(T
A
= 25˚C) (Note 3)
T
J
Max (Note 3)
θ
JA
(Note 3)
Operating Junction
Temperature
Range
Storage Temperature
Range
Lead Temperature
(Soldering, 10 seconds)
ESD Rating
Package
MM
500 mW
150˚C
250˚C/W
735 mW
150˚C
170˚C/W
(OUT − 0.3V) to (GND + 3V)
The least negative of (OUT −
0.3V) or (V+ − 6V) to (V+ + 0.3V)
120 mA
1 sec.
V+ and OUT Continuous Output Current
Output Short-Circuit Duration to GND (Note
2)
−40˚C to +85˚C
−65˚C to +150˚C
300˚C
2 kV
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, FC = Open, C
1
= C
2
= 150 µF. (Note 4)
Symbol
V+
Parameter
Supply Voltage
R
L
= 1k
Condition
Inverter, LV = Open
Inverter, LV = GND
Doubler, LV = OUT
I
Q
Supply Current
No Load
LV = Open
I
SD
V
SD
I
L
R
OUT
f
OSC
f
SW
I
OSC
P
EFF
Shutdown Supply Current
(LM2661)
Shutdown Pin Input Voltage
(LM2661)
Output Current
Output Resistance (Note 6)
Oscillator Frequency (Note 7)
Switching Frequency (Note 8)
OSC Input Current
Power Efficiency
Shutdown Mode
Normal Operation
T
A
≤
+85˚C, OUT
≤
−4V
T
A
>
+85˚C, OUT
≤
−3.8V
I
L
= 100 mA
OSC = Open
OSC = Open
FC = Open
FC = V+
R
L
(1k) between V
+
and OUT
R
L
(500) between GND and OUT
I
L
= 100 mA to GND
V
OEFF
Voltage Conversion Efficiency
No Load
99
96
92
T
A
≤
+85˚C
T
A
>
+85˚C
FC = Open
FC = V+
FC = Open
FC = V+
5
40
2.5
20
10
80
5
40
100
100
6.5
10
12
2.0
FC = Open (LM2660)
FC = V+ (LM2660) or
SD = Ground (LM2661)
Min
3.5
1.5
2.5
0.12
1
0.5
(Note 5)
0.3
Typ
Max
5.5
5.5
5.5
0.5
3
2
mA
V
Units
µA
V
mA
Ω
kHz
kHz
µA
±
2
±
16
98
96
88
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
− T
A
)/θ
JA
, where T
JMax
is the maximum junction temperature, T
A
is 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 C
2
are 0.2Ω maximum ESR capacitors. Capacitors with higher ESR will increase output resistance, reduce output
voltage and efficiency.
Note 5:
In doubling mode, when V
out
>
5V, minimum input high for shutdown equals V
out
− 3V.
Note 6:
Specified output resistance includes internal switch resistance and capacitor ESR.
Note 7:
For LM2661, the oscillator frequency is 80 kHz.
Note 8:
The output switches operate at one half of the oscillator frequency, f
OSC
= 2f
SW
.
www.national.com
2
LM2660/LM2661
Test Circuits
01291105
01291106
FIGURE 1. LM2660 and LM2661 Test Circuits
Typical Performance Characteristics
(Circuit of
Figure 1)
Output Source
Resistance vs Supply
Voltage
Supply Current vs
Supply Voltage
Supply Current vs
Oscillator Frequency
01291107
01291108
01291109
Output Source
Resistance vs
Temperature
Efficiency vs Load
Current
Output Voltage Drop
vs Load Current
01291110
01291111
01291112
3
www.national.com
LM2660/LM2661
Typical Performance Characteristics
(Circuit of
Figure 1)
Efficiency vs
Oscillator Frequency
Output Voltage vs
Oscillator Frequency
(Continued)
Oscillator Frequency
vs External
Capacitance
01291113
01291114
01291115
Oscillator Frequency
vs Supply Voltage
(FC = V+)
Oscillator Frequency
vs Supply Voltage
(FC = Open)
Oscillator Frequency
vs Temperature
(FC = V+)
01291116
01291117
01291118
Oscillator Frequency
vs Temperature
(FC = Open)
Shutdown Supply
Current vs
Temperature
(LM2661 Only)
01291119
01291120
www.national.com
4
京公网安备 11010802033920号
EEWORLD
