LTC660
100mA CMOS
Voltage Converter
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DESCRIPTION
FEATURES
■
■
■
■
■
■
■
■
Simple Conversion of 5V to – 5V Supply
Output Drive: 100mA
ROUT: 6.5Ω (0.65V Loss at 100mA)
BOOST Pin (Pin 1) for Higher Switching Frequency
Inverting and Doubling Modes
Minimum Open Circuit Voltage Conversion
Efficiency: 99%
Typical Power Conversion Efficiency
with a 100mA Load: 88%
Easy to Use
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APPLICATIONS
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Conversion of 5V to ±5V Supplies
Inexpensive Negative Supplies
Data Acquisition Systems
High Current Upgrade to LTC1044 or LTC7660
The LTC®660 is a monolithic CMOS switched-capacitor
voltage converter. It performs supply voltage conversion
from positive to negative from an input range of 1.5V to
5.5V, resulting in complementary output voltages of
– 1.5V to – 5.5V. It also performs a doubling at an input
voltage range of 2.5V to 5.5V, resulting in a doubled
output voltage of 5V to 11V. Only two external capacitors
are needed for the charge pump and charge reservoir
functions.
The converter has an internal oscillator that can be
overdriven by an external clock or slowed down when
connected to a capacitor. The oscillator runs at a 10kHz
frequency when unloaded. A higher frequency outside the
audio band can also be obtained if the BOOST pin is tied
to V +.
The LTC660 contains an internal oscillator, divide-by-two,
voltage level shifter and four power MOSFETs.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATION
Output Voltage vs
Load Current for V + = 5V
Generating – 5V from 5V
+
C1
150µF
3
4
CAP
+
OSC
LTC660
GND
CAP
–
LV
VOUT
–5.0
8
5V INPUT
TA = 25°C
ROUT = 6.5Ω
7
–4.8
6
5
–5V
OUTPUT
C2
150µF
660 TA01
OUTPUT VOLTAGE (V)
2
V+
BOOST
+
1
–4.6
–4.4
–4.2
–4.0
0
20
60
80
40
LOAD CURRENT (mA)
100
660 TA02
1
LTC660
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ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
(Note 1)
ORDER PART
NUMBER
TOP VIEW
Supply Voltage (V +) .................................................. 6V
Input Voltage on Pins 1, 6, 7
(Note 2) ............................ – 0.3V < VIN < (V + + 0.3V)
Output Short-Circuit Duration to GND
(Note 5) ............................................................. 1 sec
Power Dissipation.............................................. 500mW
Operating Temperature Range .................... 0°C to 70°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
BOOST 1
CAP
+
2
GND 3
CAP – 4
8 V+
7 OSC
LTC660CN8
LTC660CS8
6 LV
5 VOUT
N8 PACKAGE
8-LEAD PLASTIC DIP
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SOIC
660
TJMAX = 100°C, θJA = 100°C/W (N)
TJMAX = 100°C, θJA = 150°C/W (S)
Consult Factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
V + = 5V, C1 and C2 = 150µF, Boost = Open, COSC = 0pF, TA = 25°C, unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
Supply Voltage
RL = 1k
Inverter, LV = Open
Inverter, LV = GND
Doubler, LV = VOUT
●
●
●
IS
Supply Current
No Load
Boost = Open
Boost = V +
●
●
IOUT
Output Current
VOUT More Negative Than – 4V
●
ROUT
Output Resistance
IL = 100mA (Note 3)
●
fOSC
Oscillator Frequency
Boost = Open
Boost = V + (Note 4)
Power Efficiency
RL = 1k Connected Between V + and VOUT
RL = 500Ω Connected Between VOUT and GND
IL = 100mA to GND
Voltage Conversion Efficiency
No Load
Oscillator Sink or Source Current
Boost = Open
Boost = V +
The ● denotes specifications which apply over the full operating
temperature range; all other limits and typicals are at TA = 25°C.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Connecting any input terminal to voltages greater than V + or less
than ground may cause destructive latch-up. It is recommended that no
inputs from source operating from external supplies be applied prior to
power-up of the LTC660.
Note 3: The output resistance is a combination of internal switch
resistance and external capacitor ESR. To maximize output voltage and
efficiency, keep external capacitor ESR < 0.2Ω.
2
●
●
TYP
3
1.5
2.5
MAX
UNITS
5.5
5.5
5.5
V
V
V
0.08
0.23
0.5
3
mA
mA
6.5
10
100
mA
Ω
10
80
kHz
kHz
96
92
98
96
88
%
%
%
99
99.96
%
±1.1
±5.0
µA
µA
Note 4: fOSC is tested with COSC = 100pF to minimize the effects of test
fixture capacitance loading. The 0pF frequency is correlated to this 100pF
test point, and is intended to simulate the capacitance at Pin 7 when the
device is plugged into a test socket and no external capacitor is used.
Note 5: OUT may be shorted to GND for 1 sec without damage, but
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 +,
even instantaneously, or device damage may result.
LTC660
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TYPICAL PERFORMANCE CHARACTERISTICS (Using Test Circuit in Figure 1)
100
1000
300
TA = 25°C
V + = 5V
SUPPLY CURRENT (µA)
250
200
150
BOOST = V +
100
BOOST = OPEN
TA = 25°C
V + = 5V
BOOST = OPEN
90
OUTPUT RESISTANCE (Ω)
TA = 25°C
SUPPLY CURRENT (µA)
Output Resistance
vs Oscillator Frequency
Supply Current
vs Oscillator Frequency
Supply Current vs Supply Voltage
100
10
50
80
70
60
C1 = C2 = 150µF
C1 = C2 = 1500µF
50
40
C1 = C2 = 22µF
30
20
10
0
1.5
2
4 4.5
2.5 3 3.5
SUPPLY VOLTAGE (V)
5
1
0.01
5.5
0.1
100
1
10
OSCILLATOR FREQUENCY (kHz)
Output Resistance
vs Supply Voltage
–3.0
100
BOOST = OPEN
10
8
6
4
LTC660
EFFICIENCY
–3.4
20
V + = 1.5V
15
V + = 3V
10
V + = 5V
OUTPUT VOLTAGE (V)
OUTPUT RESISTANCE (Ω)
12
TA = 25°C
BOOST = OPEN
88
–3.8
84
–4.2
76
80
LTC660
OUTPUT VOLTAGE
–4.6
5
72
68
2
64
0
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
0
1
3
4
2
SUPPLY VOLTAGE (V)
5
6
100
TA = 25°C
BOOST = OPEN
V + = 5.5V
Output Voltage Drop
vs Load Current
V + = 5.5V
V + = 4.5V
V + = 3.5V
75
70
V + = 1.5V
V + = 2.5V
EFFICIENCY (%)
90
80
85
+
V = 2.5V
70
60
60
LTC660 • TPC07
V + = 3.5V
75
65
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
V + = 4.5V
80
65
0
LTC660 • TPC06
1.0
TA = 25°C
BOOST = V +
95
90
85
60
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
Efficiency vs Load Current
Efficiency vs Load Current
95
0
LTC660 • TPC05
LTC690 • TPC04
100
–5.0
V + = 1.5V
TA = 25°C
BOOST = OPEN
0.9
OUTPUT VOLTAGE DROP FROM
SUPPLY VOLTAGE (V)
0
EFFICIENCY (%)
96
92
EFFICIENCY (%)
OUTPUT RESISTANCE (Ω)
Output Voltage and Efficiency
vs Load Current, V + = 5V
25
14
100
LTC660 • TPC03
Output Resistance vs Temperature
TA = 25°C
BOOST = OPEN
16
1
10
OSCILLATOR FREQUENCY (kHz)
LTC660 • G02
LTC660 • G01
18
0
0.1
1000
0.8
V + = 2.5V
0.7
+
V = 1.5V
0.6
0.5
V + = 3.5V
V + = 4.5V
0.4
0.3
V + = 5.5V
0.2
0.1
0
0
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
LTC660 • TPC08
0
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
LTC660 • TPC09
3
LTC660
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TYPICAL PERFORMANCE CHARACTERISTICS (Using Test Circuit in Figure 1)
Output Voltage Drop
vs Load Current
Output Voltage
vs Oscillator Frequency
1.0
TA = 25°C
BOOST = V +
IL = 1mA
0.8
95
90
–4.5
V + = 2.5V
0.6
0.5
V + = 1.5V
0.4
V + = 3.5V
V + = 4.5V
0.3
V + = 5.5V
0.2
IL = 10mA
–4.0
IL = 80mA
–3.5
–3.0
TA =25°C
V+ = 5V
BOOST = OPEN
0.1
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
1
10
OSCILLATOR FREQUENCY (kHz)
LTC660 • TPC10
70
55
50
0.1
100
6
4
2
70
60
50
40
30
20
10
8
6
4
2
V+ = 5V
BOOST = OPEN
OSC = OPEN
0
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
LTC660 • TPC15
LTC660 • TPC14
LTC660 • TPC13
Oscillator Frequency
vs External Capacitance
Oscillator Frequency
vs Temperature
100
100
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY (kHz)
90
80
70
60
50
40
30
20
10
V+ = 5V
BOOST = V+
OSC = OPEN
0
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
LTC660 • TPC16
4
100
12
TA = 25°C
90 BOOST = V+
OSC = OPEN
80
10
0
1
10
OSCILLATOR FREQUENCY (kHz)
Oscillator Frequency
vs Temperature
OSCILLATOR FREQUENCY (kHz)
8
TA = 25°C
V+ = 5V
BOOST = OPEN
LTC660 • TPC12
100
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY (kHz)
10
IL = 1mA
75
Oscillator Frequency
vs Supply Voltage
TA = 25°C
BOOST = OPEN
OSC = OPEN
IL = 80mA
LTC660 • TPC11
Oscillator Frequency
vs Supply Voltage
12
IL = 10mA
80
60
–2.5
0
85
65
0.1
0
EFFICIENCY (%)
0.7
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE DROP FROM
SUPPLY VOLTAGE (V)
0.9
Efficiency vs Oscillator Frequency
100
–5.0
BOOST = V +
10
1
BOOST = OPEN
0.1
00.1
1
10
100
1000
CAPACITANCE (pF)
10000
LTC660 • TPC17
LTC660
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PIN
NAME
INVERTER
DOUBLER
1
BOOST
Internal Oscillator Frequency Control Pin.
BOOST = Open, fOSC = 10kHz typ;
BOOST = V +, fOSC = 80kHz typ; when OSC is driven
externally BOOST has no effect.
Same
2
CAP +
Positive Terminal for Charge Pump Capacitor
Same
3
GND
Power Supply Ground Input
Positive Voltage Input
4
CAP –
Negative Terminal for Charge Pump Capacitor
Same
5
VOUT
Negative Voltage Output
Power Supply Ground Input
6
LV
Tie LV to GND when the input voltage is less than 3V.
LV may be connected to GND or left open for input
voltages above 3V. Connect LV to GND when
overdriving OSC.
LV must be tied to VOUT for all input voltages.
7
OSC
An external capacitor can be connected to this pin to
slow the oscillator frequency. Keep stray capacitance
to a minimum. An external oscillator can be applied
to this pin to overdrive the internal oscillator.
Same except standard logic levels will not be able to
overdrive OSC pin.
8
V+
Positive Voltage Input
Positive Voltage Output
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PIN FUNCTIONS
TEST CIRCUIT
+
C1
150µF
1
8
2
7
3
4
LTC660
IS
V+
5V
EXTERNAL
OSCILLATOR
6
COSC
5
RL
IL
+
V+
C1
150µF
VOUT
LTC660 • F01
Figure 1. Test Circuit
5
LTC660
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APPLICATIONS INFORMATION
Theory of Operation
V+
(8)
I = f • ∆q = f • C1 (V1 – V2)
Rewriting in terms of voltage and impedance equivalence,
I=
V1 − V2 V1 − V2
=
1/ fC1 REQUIV
A new variable REQUIV has been defined such that
REQUIV = 1/fC1. Thus, the equivalent circuit for the switchedcapacitor network is as shown in Figure 3.
Figure 4 shows that the LTC660 has the same switching
action as the basic switched-capacitor building block.
V2
V1
C1
C2
RL
660 F02
Figure 2. Switched-Capacitor Building Block
REQUIV
V2
V1
C2
RL
SW2
CAP+
(2)
BOOST
φ
4.5×
(1)
+
C1
OSC
+2
φ
OSC
(7)
CAP –
(4)
VOUT
(5)
C2
LV
(6)
∆q = q1 – q2 = C1 (V1 – V2)
If the switch is cycled “f” times per second, the charge
transfer per unit time (i.e., current) is:
SW1
+
To understand the theory of operation for the LTC660, a
review of a basic switched-capacitor building block is
helpful. In Figure 2, when the switch is in the left position,
capacitor C1 will charge to voltage V1. The total charge on
C1 will be q1 = C1V1. The switch then moves to the right,
discharging C1 to voltage V2. After this discharging time,
the charge on C1 is q2 = C1V2. Note that charge has been
transferred from the source V1 to the output V2. The
amount of charge transferred is:
CLOSED WHEN
V+ > 3.0V
GND
(3)
LTC660 • F04
Figure 4. LTC660 Switched-Capacitor Voltage Converter
Block Diagram
This simplified circuit does not include finite on-resistance
of the switches and output voltage ripple, however, it does
give an intuitive feel for how the device works. For example, if you examine power conversion efficiency as a
function of frequency this simple theory will explain how
the LTC660 behaves. The loss and hence the efficiency is
set by the output impedance. As frequency is decreased,
the output impedance will eventually be dominated by the
1/fC1 term and voltage losses will rise decreasing the
efficiency. As the frequency increases the quiescent current increases. At high frequency this current loss becomes significant and the power efficiency starts to decrease.
The LTC660 oscillator frequency is designed to run where
the voltage loss is a minimum. With the external 150µF
capacitors the effective output impedance is determined
by the internal switch resistances and the capacitor ESRs.
LV (Pin 6)
The internal logic of the LTC660 runs between V + and LV
(Pin 6). For V + ≥ 3V, an internal switch shorts LV to ground
(Pin 3). For V + < 3V, the LV pin should be tied to ground.
For V + ≥ 3V, the LV pin can be tied to ground or left floating.
OSC (Pin 7) and BOOST (Pin 1)
1
REQUIV =
fC1
660 F03
Figure 3. Switched-Capacitor Equivalent Circuit
6
The switching frequency can be raised, lowered or driven
from an external source. Figure 5 shows a functional
diagram of the oscillator circuit.
LTC660
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APPLICATIONS INFORMATION
V+
7.0I
V+
REQUIRED FOR TTL LOGIC
NC
I
+
BOOST
(1)
C1
1
8
2
7
3
LTC660
4
100k
OSC INPUT
6
5
–(V +)
C2
+
OSC
(7)
SCHMITT
TRIGGER
Figure 6. External Clocking
∼18pF
7.0I
LTC660 • F06
I
LV
(6)
LTC660 • F05
Figure 5. Oscillator
By connecting the BOOST pin (Pin 1) to V +, the charge and
discharge current is increased and, hence, the frequency
is increased by approximately four and a half times.
Increasing the frequency will decrease output impedance
and ripple for high load currents.
Loading Pin 7 with more capacitance will lower the frequency. Using the BOOST (Pin 1) in conjunction with
external capacitance on Pin 7 allows user selection of the
frequency over a wide range.
Driving the LTC660 from an external frequency source can
be easily achieved by driving Pin 7 and leaving the BOOST
pin open, as shown in Figure 6. The output current from
Pin 7 is small, typically 1.1µA to 8µA, so a logic gate is
capable of driving this current. (A CMOS logic gate can be
used to drive the OSC pin.) For 5V applications, a TTL logic
gate can be used by simply adding an external pull-up
resistor (see Figure 6).
Capacitor Selection
While the exact values of C1 and C2 are noncritical, good
quality, low ESR capacitors are necessary to minimize
voltage losses at high currents. For C1 the effect of the ESR
of the capacitor will be multiplied by four, due to the fact
the switch currents are approximately two times higher
than the output current and losses will occur on both the
charge and discharge cycle. This means using a capacitor
with 1Ω of ESR for C1 will have the same effect as
increasing the output impedance of the LTC660 by 4Ω.
This represents a significant increase in the voltage losses.
For C2 the effect of ESR is less dramatic. A C2 with 1Ω of
ESR will increase the output impedance by 1Ω. The size
of C2 and the load current will determine the output
voltage ripple. It is alternately charged and discharged at
a current approximately equal to the output current. This
will cause a step function to occur in the output voltage at
the switch transitions. For example, for a switching frequency of 5kHz (one-half the nominal 10kHz oscillator
frequency) and C2 = 150µF with an ESR of 0.2Ω, ripple is
approximately 90mV with a 100mA load current.
7
LTC660
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TYPICAL APPLICATIONS N
Negative Voltage Converter
Voltage Doubling
Figure 7 shows a typical connection which will provide a
negative supply from an available positive supply. This
circuit operates over full temperature and power supply
ranges without the need of any external diodes. The LV pin
(Pin 6) is shown grounded, but for V + ≥ 3V, it may be
floated, since LV is internally switched to ground (Pin 3)
for V + ≥ 3V.
Figure 8 shows the LTC660 operating in the voltage
doubling mode. The external Schottky (1N5817) diode is
for start-up only. The output voltage is 2 • VIN without a
load. The diode has no effect on the output voltage.
1
V+
BOOST
1N5817*
1
8
VIN
1.5V TO 5.5V
7
CAP+
OSC
LTC660
6
3
GND
LV
2
+
C1
150µF
4
CAP –
VOUT
VIN
2.5V
TO 5.5V
5
C1
150µF
2
+
3
4
CAP
+
OSC
LTC660
GND
LV
CAP –
VOUT
VOUT = –VIN
C2
150µF
V+
BOOST
8
+
7
VOUT = 2VIN
C2
150µF
6
5
* SCHOTTKY DIODE IS FOR START-UP ONLY
LTC660 • F08
Figure 8. Voltage Doubler
+
LTC660 • F07
Figure 7. Voltage Inverter
Ultraprecision Voltage Divider
The output voltage (Pin 5) characteristics of the circuit are
those of a nearly ideal voltage source in series with a 6.5Ω
resistor. The 6.5Ω output impedance is composed of two
terms: 1) the equivalent switched-capacitor resistance
(see Theory of Operation), and 2) a term related to the onresistance of the MOS switches.
At an oscillator frequency of 10kHz and C1 = 150µF, the
first term is:
R EQUIV =
(f
1
)
OSC /2 C1
1
5 • 103 • 150
• 10 –6
=
+
C1
150µF
V+
± 0.002%
2
TMIN ≤ TA ≤ TMAX
IL ≤ 100nA
+
1
8
2
7
3
4
LTC660
V+
3V TO 11V
6
5
C2
150µF
= 1.3Ω.
Notice that the equation for REQUIV is not a capacitive
reactance equation (XC = 1/ωC) and does not contain a
2π term.
The exact expression for output impedance is complex,
but the dominant effect of the capacitor is clearly shown on
the typical curves of output impedance and power efficiency versus frequency. For C1 = C2 = 150µF, the output
impedance goes from 6.5Ω at fOSC = 10kHz to 110Ω at
fOSC = 100Hz. As the 1/fC term becomes large compared
to the switch on-resistance term, the output resistance is
determined by 1/fC only.
8
An ultraprecision voltage divider is shown in Figure 9. To
achieve the 0.002% accuracy indicated, the load current
should be kept below 100nA. However, with a slight loss
in accuracy, the load current can be increased.
LTC660 • F09
Figure 9. Ultraprecision Voltage Divider
Battery Splitter
A common need in many systems is to obtain positive and
negative supplies from a single battery or single power
supply system. Where current requirements are small, the
circuit shown in Figure 10 is a simple solution. It provides
symmetrical positive or negative output voltages, both
equal to one-half the input voltage. The output voltages are
both referenced to Pin 3 (Output Common).
LTC660
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TYPICAL APPLICATIONS N
VB
(9V)
1
2
C1
150µF
3
+VB/2 (4.5V)
7
LTC660
4
6
5
–VB/2 (–4.5V)
C2
150µF
+
OUTPUT COMMON
3V ≤ VB ≤ 11V
Additional flexibility of the LTC660 is shown in Figures 11
and 12. Figure 11 shows two LTC660s connected in
parallel to provide a lower effective output resistance. If,
however, the output resistance is dominated by 1/fC1,
increasing the capacitor size (C1) or increasing the frequency will be of more benefit than the paralleling circuit
shown.
LTC1046 • TA10
Stacking for Higher Voltage
Figure 10. Battery Splitter
Figure 12 makes use of “stacking” two LTC660s to provide
even higher voltages. In Figure 12, a negative voltage
doubler or tripler can be achieved depending upon how
Pin 8 of the second LTC660 is connected, as shown
schematically by the switch.
V+
+
1
8
1
2
7
2
3
C1
150µF
LTC660
+
6
4
5
3
C1
150µF
8
7
LTC660
4
6
5
VOUT = –V +
1/4 CD4077
+
C2
150µF
OPTIONAL SYNCHRONIZATION
CIRCUIT TO MINIMIZE RIPPLE
LTC660 • F11
Figure 11. Paralleling for 200mA Load Current
FOR VOUT = –3V +
V+
7
3
4
LTC660
1
150µF
6
5
1
3
–V +
8
7
2
LTC660
2
4
6
5
VOUT
150µF
+
150µF
8
2
FOR VOUT = –2V +
150µF
+
+
1
+
+
Paralleling for Lower Output Resistance
8
LTC660 • F12
Figure 12. Stacking for High Voltage
9
LTC660
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PACKAGE DESCRIPTION
Dimensions in inches (millimeters) unless otherwise noted.
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
0.255 ± 0.015*
(6.477 ± 0.381)
0.300 – 0.325
(7.620 – 8.255)
0.009 – 0.015
(0.229 – 0.381)
(
+0.035
0.325 –0.015
8.255
+0.889
–0.381
)
0.045 – 0.065
(1.143 – 1.651)
0.065
(1.651)
TYP
0.100 ± 0.010
(2.540 ± 0.254)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
10
0.130 ± 0.005
(3.302 ± 0.127)
0.125
(3.175) 0.020
MIN (0.508)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
N8 1197
LTC660
U
PACKAGE DESCRIPTION
Dimensions in inches (millimeters) unless otherwise noted.
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
8
7
6
5
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
0.053 – 0.069
(1.346 – 1.752)
0°– 8° TYP
0.016 – 0.050
0.406 – 1.270
0.014 – 0.019
(0.355 – 0.483)
2
3
4
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SO8 0996
11
LTC660
U
TYPICAL APPLICATIONS N
Voltage Inverter
1
V+
BOOST
8
VIN
1.5V TO 5.5V
7
CAP+
OSC
LTC660
6
3
GND
LV
2
+
C1
150µF
4
CAP –
VOUT
5
VOUT = –VIN
C2
150µF
+
LTC660 • F07
Voltage Doubler
1N5817*
1
VIN
2.5V
TO 5.5V
C1
150µF
+
2
3
4
V+
BOOST
CAP
+
OSC
LTC660
GND
CAP –
LV
VOUT
8
7
+
VOUT = 2VIN
C2
150µF
6
5
* SCHOTTKY DIODE IS FOR START-UP ONLY
LTC660 • F08
RELATED PARTS
PART NUMBER
OUTPUT CURRENT
MAXIMUM VIN
COMMENTS
LTC660
100mA
6V
LTC1046
50mA
6V
LTC1044
20mA
9.5V
LTC1044A
20mA
13V
LTC1144
20mA
20V
Highest Voltage
LT1054
100mA
16V
Adjustable Output
LTC1262
30mA
6V
12V Fixed Output
LTC1261
10mA
9V
– 4V, – 4.5V and Adjustable
Outputs
Unregulated Output Voltage
Highest Current
Lowest Cost
Regulated Output Voltage
All devices are available in plastic 8-lead SO and PDIP packages
12
Linear Technology Corporation
LT/GP 0598 2K REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
LINEAR TECHNOLOGY CORPORATION 1995
工商网监
湘ICP备2023018690号
