1

LTC660

100mA CMOSVoltage Converter

TYPICAL APPLICATION

U

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

The LTC®660 is a monolithic CMOS switched-capacitorvoltage converter. It performs supply voltage conversionfrom positive to negative from an input range of 1.5V to5.5V, resulting in complementary output voltages of–1.5V to – 5.5V. It also performs a doubling at an inputvoltage range of 2.5V to 5.5V, resulting in a doubledoutput voltage of 5V to 11V. Only two external capacitorsare needed for the charge pump and charge reservoirfunctions.

The converter has an internal oscillator that can beoverdriven by an external clock or slowed down whenconnected to a capacitor. The oscillator runs at a 10kHzfrequency when unloaded. A higher frequency outside theaudio band can also be obtained if the BOOST pin is tiedto V +.

The LTC660 contains an internal oscillator, divide-by-two,voltage level shifter and four power MOSFETs.

Conversion of 5V to ±5V Supplies Inexpensive Negative Supplies Data Acquisition Systems High Current Upgrade to LTC1044 or LTC7660

FEATURES DESCRIPTION

U

APPLICATIONSU

Output Voltage vsLoad Current for V+ = 5V

LOAD CURRENT (mA)0

OUTP

UT V

OLTA

GE (V

)

–5.0

–4.8

–4.6

–4.4

–4.2

–4.080

660 TA02

20 40 60 100

TA = 25°C ROUT = 6.5Ω

, LTC and LT are registered trademarks of Linear Technology Corporation.

Generating – 5V from 5V

1

2

3

4

8

7

6

5

BOOST

CAP+

GND

CAP–

C2 150µF

660 TA01

C1 150µF

–5V OUTPUT

5V INPUT

LTC660

V+

OSC

LV

VOUT

+

+

2

LTC660

ABSOLUTE MAXIMUM RATINGS

W WW U

PACKAGE/ORDER INFORMATION

W UU

Supply Voltage (V +) .................................................. 6VInput Voltage on Pins 1, 6, 7

(Note 2) ............................ –0.3V < VIN < (V + + 0.3V)Output Short-Circuit Duration to GND

(Note 5) ............................................................. 1 secPower Dissipation .............................................. 500mWOperating Temperature Range .................... 0°C to 70°CStorage Temperature Range ................. –65°C to 150°CLead Temperature (Soldering, 10 sec).................. 300°C

(Note 1)

1

2

3

4

8

7

6

5

TOP VIEW

BOOST

CAP+

GND

CAP–

V+

OSC

LV

VOUT

N8 PACKAGE

8-LEAD PLASTIC DIP

S8 PACKAGE 8-LEAD PLASTIC SOIC

660TJMAX = 100°C, θJA = 100°C/W (N)TJMAX = 100°C, θJA = 150°C/W (S)

Consult Factory for Industrial and Military grade parts.

LTC660CN8LTC660CS8

ORDER PARTNUMBER

S8 PART MARKING

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Supply Voltage RL = 1k Inverter, LV = Open 3 5.5 VInverter, LV = GND 1.5 5.5 VDoubler, LV = VOUT 2.5 5.5 V

IS Supply Current No Load Boost = Open 0.08 0.5 mABoost = V + 0.23 3 mA

IOUT Output Current VOUT More Negative Than –4V 100 mA

ROUT Output Resistance IL = 100mA (Note 3) 6.5 10 Ω

fOSC Oscillator Frequency Boost = Open 10 kHzBoost = V + (Note 4) 80 kHz

Power Efficiency RL = 1k Connected Between V + and VOUT 96 98 %RL = 500Ω Connected Between VOUT and GND 92 96 %IL = 100mA to GND 88 %

Voltage Conversion Efficiency No Load 99 99.96 %

Oscillator Sink or Source Current Boost = Open ±1.1 µABoost = V + ±5.0 µA

V+ = 5V, C1 and C2 = 150µF, Boost = Open, COSC = 0pF, TA = 25°C, unless otherwise noted.ELECTRICAL CHARACTERISTICS

The denotes specifications which apply over the full operatingtemperature range; all other limits and typicals are at TA = 25°C.Note 1: Absolute Maximum Ratings are those values beyond which the lifeof a device may be impaired.Note 2: Connecting any input terminal to voltages greater than V + or lessthan ground may cause destructive latch-up. It is recommended that noinputs from source operating from external supplies be applied prior topower-up of the LTC660.Note 3: The output resistance is a combination of internal switchresistance and external capacitor ESR. To maximize output voltage andefficiency, keep external capacitor ESR < 0.2Ω.

Note 4: fOSC is tested with COSC = 100pF to minimize the effects of testfixture capacitance loading. The 0pF frequency is correlated to this 100pFtest point, and is intended to simulate the capacitance at Pin 7 when thedevice 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, butshorting 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.

3

LTC660

TYPICAL PERFORMANCE CHARACTERISTICS

UW

(Using Test Circuit in Figure 1)

Output Voltage and Efficiencyvs Load Current, V+ = 5V

LOAD CURRENT (mA)0

OUTP

UT V

OLTA

GE (V

)

EFFICIENCY (%)

–3.8

–3.4

–3.0

80

LTC660 • TPC06

–4.2

–4.6

–5.0

84

92

100

76

68

80

88

96

72

64

6020 40 6010 9030 50 70 100

LTC660 EFFICIENCY

LTC660 OUTPUT VOLTAGE

TA = 25°C BOOST = OPEN

OSCILLATOR FREQUENCY (kHz)0.1

40

OUTP

UT R

ESIS

TANC

E (Ω

)

50

60

70

80

1 10 100

LTC660 • TPC03

30

20

10

0

90

100

C1 = C2 = 22µF

C1 = C2 = 150µFC1 = C2 = 1500µF

TA = 25°C V+ = 5V BOOST = OPEN

Output Resistancevs Oscillator Frequency

LOAD CURRENT (mA)0

EFFI

CIEN

CY (%

)

90

100

80

LTC660 • TPC07

80

70

85

95

75

65

6020 40 6010 9030 50 70 100

V+ = 5.5V

TA = 25°C BOOST = OPEN

V+ = 4.5V

V+ = 3.5V

V+ = 2.5VV+ = 1.5V

Efficiency vs Load Current

SUPPLY VOLTAGE (V)0

0

OUTP

UT R

ESIS

TANC

E (Ω

)

2

6

8

10

2

18

LTC690 • TPC04

4

1 3 4 5 6

12

14

16TA = 25°C BOOST = OPEN

Output Resistancevs Supply Voltage

TEMPERATURE (°C)–60

OUTP

UT R

ESIS

TANC

E (Ω

)

15

20

25

100

LTC660 • TPC05

10

5

0–20 20 60 14080–40 0 40 120

V+ = 1.5V

BOOST = OPEN

V+ = 3V

V+ = 5V

Output Resistance vs Temperature

Output Voltage Dropvs Load Current

LOAD CURRENT (mA)0

OUTP

UT V

OLTA

GE D

ROP

FROM

SU

PPLY

VOL

TAGE

(V)

0.8

1.0

80

LTC660 • TPC09

0.6

0.4

0.7

0.9

0.5

0.3

0.2

0.1

020 40 6010 9030 50 70 100

V+ = 5.5V

TA = 25°C BOOST = OPEN

V+ = 2.5V

V+ = 1.5V

V+ = 3.5V V+ = 4.5V

Efficiency vs Load Current

LOAD CURRENT (mA)0

EFFI

CIEN

CY (%

)

90

100

80

LTC660 • TPC08

80

70

85

95

75

65

6020 40 6010 9030 50 70 100

V+ = 5.5V

TA = 25°C BOOST = V+

V+ = 3.5V

V+ = 2.5V

V+ = 1.5V

V+ = 4.5V

SUPPLY VOLTAGE (V)1.5

0

SUPP

LY C

URRE

NT (µ

A)

50

100

150

200

2.5 3.5 4.5 5.5

LTC660 • G01

250

300

2 3 4 5

BOOST = V+

BOOST = OPEN

TA = 25°C

Supply Current vs Supply Voltage

OSCILLATOR FREQUENCY (kHz)

10

100

SUPP

LY C

URRE

NT (µ

A)

1000

0.01 1 10 1000

LTC660 • G02

10.1 100

TA = 25°C V+ = 5V

Supply Currentvs Oscillator Frequency

4

LTC660

TYPICAL PERFORMANCE CHARACTERISTICS

UW

(Using Test Circuit in Figure 1)

Oscillator Frequencyvs Temperature

TEMPERATURE (°C)

0

OSCI

LLAT

OR F

REQU

ENCY

(kHz

)

4

8

12

2

6

10

–20 20 60 100

LTC660 • TPC15

140–40–60 0 40 80 120

V+ = 5V BOOST = OPEN OSC = OPEN

LOAD CURRENT (mA)0

OUTP

UT V

OLTA

GE D

ROP

FROM

SU

PPLY

VOL

TAGE

(V)

0.8

1.0

80

LTC660 • TPC10

0.6

0.4

0.7

0.9

0.5

0.3

0.2

0.1

020 40 6010 9030 50 70 100

V+ = 5.5V

TA = 25°C BOOST = V+

V+ = 2.5V

V+ = 1.5V

V+ = 3.5V V+ = 4.5V

Output Voltage Dropvs Load Current

Output Voltagevs Oscillator Frequency

OSCILLATOR FREQUENCY (kHz)0.1

–2.5

OUTP

UT V

OLTA

GE (V

)

–4.0

–4.5

–5.0

1 10 100

LTC660 • TPC11

–3.5

–3.0 TA =25°C V+ = 5V

BOOST = OPEN

IL = 1mA

IL = 10mA

IL = 80mA

Efficiency vs Oscillator Frequency

OSCILLATOR FREQUENCY (kHz)0.1

70

EFFI

CIEN

CY (%

)

75

80

85

90

1 10 100

LTC660 • TPC12

65

60

55

50

95

100

TA = 25°C V+ = 5V BOOST = OPEN

IL = 10mA IL = 80mA

IL = 1mA

Oscillator Frequencyvs Supply Voltage

SUPPLY VOLTAGE (V)

0

OSCI

LLAT

OR F

REQU

ENCY

(kHz

)

4

8

12

2

6

10

1.0 2.5 3.5 4.5

LTC660 • TPC13

5.50.50 1.5 2.0 3.0 4.0 5.0

TA = 25°C BOOST = OPEN OSC = OPEN

Oscillator Frequencyvs Supply Voltage

SUPPLY VOLTAGE (V)

0

OSCI

LLAT

OR F

REQU

ENCY

(kHz

)

60

50

40

30

20

80

100

10

70

90

1.0 2.5 3.5 4.5

LTC660 • TPC14

5.50.50 1.5 2.0 3.0 4.0 5.0

TA = 25°C BOOST = V+ OSC = OPEN

Oscillator Frequencyvs Temperature

TEMPERATURE (°C)–60

OSCI

LLAT

OR F

REQU

ENCY

(kHz

)

60

80

100

100

LTC660 • TPC16

40

20

10

70

90

50

30

0–20 20 60–40 1200 40 80 140

V+ = 5V BOOST = V+ OSC = OPEN

Oscillator Frequencyvs External Capacitance

CAPACITANCE (pF)

00.1

OSCI

LLAT

OR F

REQU

ENCY

(kHz

)

1

100

1000100101 10000

LTC660 • TPC17

0.1

10BOOST = V+

BOOST = OPEN

5

LTC660

PIN NAME INVERTER DOUBLER

1 BOOST Internal Oscillator Frequency Control Pin. SameBOOST = Open, fOSC = 10kHz typ;BOOST = V +, fOSC = 80kHz typ; when OSC is drivenexternally BOOST has no effect.

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 must be tied to VOUT for all input voltages.LV may be connected to GND or left open for inputvoltages above 3V. Connect LV to GND whenoverdriving OSC.

7 OSC An external capacitor can be connected to this pin to Same except standard logic levels will not be able toslow the oscillator frequency. Keep stray capacitance overdrive OSC pin.to a minimum. An external oscillator can be appliedto this pin to overdrive the internal oscillator.

8 V + Positive Voltage Input Positive Voltage Output

PIN FUNCTIONS

UUU

TEST CIRCUIT

V+

LTC660

1

2

3

4

8

7

6

5

C1 150µF

V+ 5V

EXTERNAL OSCILLATOR

COSC

VOUTLTC660 • F01

RL

IS

IL

C1 150µF

+

+

Figure 1. Test Circuit

6

LTC660

APPLICATIONS INFORMATION

WU UU

Theory of Operation

To understand the theory of operation for the LTC660, areview of a basic switched-capacitor building block ishelpful. In Figure 2, when the switch is in the left position,capacitor C1 will charge to voltage V1. The total charge onC1 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 beentransferred from the source V1 to the output V2. Theamount of charge transferred is:

∆q = q1 – q2 = C1 (V1 – V2)

If the switch is cycled “f” times per second, the chargetransfer per unit time (i.e., current) is:

I = f • ∆q = f • C1 (V1 – V2)

Rewriting in terms of voltage and impedance equivalence,

IV V

fCV VREQUIV

= − = −1 21 1

1 2/

A new variable REQUIV has been defined such thatREQUIV = 1/fC1. Thus, the equivalent circuit for the switched-capacitor network is as shown in Figure 3.

Figure 4 shows that the LTC660 has the same switchingaction as the basic switched-capacitor building block.

Figure 2. Switched-Capacitor Building Block

Figure 3. Switched-Capacitor Equivalent Circuit

LTC660 • F04

CAP+ (2)

CAP– (4)

GND (3)

VOUT (5)

V+ (8)

LV (6)

4.5× (1)

OSC (7)

OSC +2

CLOSED WHEN V+ > 3.0V

C1

C2

BOOST

SW1 SW2

φ

φ

+

+

Figure 4. LTC660 Switched-Capacitor Voltage ConverterBlock Diagram

This simplified circuit does not include finite on-resistanceof the switches and output voltage ripple, however, it doesgive an intuitive feel for how the device works. For ex-ample, if you examine power conversion efficiency as afunction of frequency this simple theory will explain howthe LTC660 behaves. The loss and hence the efficiency isset by the output impedance. As frequency is decreased,the output impedance will eventually be dominated by the1/fC1 term and voltage losses will rise decreasing theefficiency. As the frequency increases the quiescent cur-rent increases. At high frequency this current loss be-comes significant and the power efficiency starts to de-crease.

The LTC660 oscillator frequency is designed to run wherethe voltage loss is a minimum. With the external 150µFcapacitors the effective output impedance is determinedby 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)

The switching frequency can be raised, lowered or drivenfrom an external source. Figure 5 shows a functionaldiagram of the oscillator circuit.

C1 C2

V2

660 F02

V1

RL

C2

V2

660 F03

V1

RL

REQUIV

REQUIV =1

fC1

7

LTC660

APPLICATIONS INFORMATION

WU UU

Figure 5. Oscillator

OSC (7)

LTC660 • F05

LV (6)

BOOST (1)

∼18pF

I

I7.0I

7.0I

V+

SCHMITT TRIGGER

Figure 6. External Clocking

Capacitor Selection

While the exact values of C1 and C2 are noncritical, goodquality, low ESR capacitors are necessary to minimizevoltage losses at high currents. For C1 the effect of the ESRof the capacitor will be multiplied by four, due to the factthe switch currents are approximately two times higherthan the output current and losses will occur on both thecharge and discharge cycle. This means using a capacitorwith 1Ω of ESR for C1 will have the same effect asincreasing 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 ofESR will increase the output impedance by 1Ω. The sizeof C2 and the load current will determine the outputvoltage ripple. It is alternately charged and discharged ata current approximately equal to the output current. Thiswill cause a step function to occur in the output voltage atthe switch transitions. For example, for a switching fre-quency of 5kHz (one-half the nominal 10kHz oscillatorfrequency) and C2 = 150µF with an ESR of 0.2Ω, ripple isapproximately 90mV with a 100mA load current.

By connecting the BOOST pin (Pin 1) to V+, the charge anddischarge current is increased and, hence, the frequencyis increased by approximately four and a half times.Increasing the frequency will decrease output impedanceand ripple for high load currents.

Loading Pin 7 with more capacitance will lower the fre-quency. Using the BOOST (Pin 1) in conjunction withexternal capacitance on Pin 7 allows user selection of thefrequency over a wide range.

Driving the LTC660 from an external frequency source canbe easily achieved by driving Pin 7 and leaving the BOOSTpin open, as shown in Figure 6. The output current fromPin 7 is small, typically 1.1µA to 8µA, so a logic gate iscapable of driving this current. (A CMOS logic gate can beused to drive the OSC pin.) For 5V applications, a TTL logicgate can be used by simply adding an external pull-upresistor (see Figure 6).

8

7

6

54

3

2

1

C1

C2

–(V+)

V+

100k

REQUIRED FOR TTL LOGIC

LTC660 • F06

NC

OSC INPUTLTC660+

+

8

LTC660

TYPICAL APPLICATIONS N

U

Voltage Doubling

Figure 8 shows the LTC660 operating in the voltagedoubling mode. The external Schottky (1N5817) diode isfor start-up only. The output voltage is 2 • VIN without aload. The diode has no effect on the output voltage.

1

2

3

4

8

7

6

5

BOOST

CAP+

GND

CAP–

LTC660 • F08

C1 150µF

VOUT = 2VIN

VIN 2.5V

TO 5.5V

LTC660

1N5817*

V+

OSC

LV

VOUT

C2 150µF

* SCHOTTKY DIODE IS FOR START-UP ONLY

++

Figure 8. Voltage Doubler

Negative Voltage Converter

Figure 7 shows a typical connection which will provide anegative supply from an available positive supply. Thiscircuit operates over full temperature and power supplyranges without the need of any external diodes. The LV pin(Pin 6) is shown grounded, but for V+ ≥ 3V, it may befloated, since LV is internally switched to ground (Pin 3)for V + ≥ 3V.

The output voltage (Pin 5) characteristics of the circuit arethose of a nearly ideal voltage source in series with a 6.5Ωresistor. The 6.5Ω output impedance is composed of twoterms: 1) the equivalent switched-capacitor resistance(see Theory of Operation), and 2) a term related to the on-resistance of the MOS switches.

At an oscillator frequency of 10kHz and C1 = 150µF, thefirst term is:

R =1

f /2EQUIV

OSC( ) =

=

C1

15 10 150 10

1 33 6• • •

.–

Ω.

Notice that the equation for REQUIV is not a capacitivereactance equation (XC = 1/ωC) and does not contain a2π term.

The exact expression for output impedance is complex,but the dominant effect of the capacitor is clearly shown onthe typical curves of output impedance and power effi-ciency versus frequency. For C1 = C2 = 150µF, the outputimpedance goes from 6.5Ω at fOSC = 10kHz to 110Ω atfOSC = 100Hz. As the 1/fC term becomes large comparedto the switch on-resistance term, the output resistance isdetermined by 1/fC only.

Ultraprecision Voltage Divider

An ultraprecision voltage divider is shown in Figure 9. Toachieve the 0.002% accuracy indicated, the load currentshould be kept below 100nA. However, with a slight lossin accuracy, the load current can be increased.

1

2

3

4

8

7

6

5

BOOST

CAP+

GND

CAP–

C2 150µF

LTC660 • F07

C1 150µF

VOUT = –VIN

VIN 1.5V TO 5.5V

LTC660

V+

OSC

LV

VOUT

+

+

Figure 7. Voltage Inverter

Battery Splitter

A common need in many systems is to obtain positive andnegative supplies from a single battery or single powersupply system. Where current requirements are small, thecircuit shown in Figure 10 is a simple solution. It providessymmetrical positive or negative output voltages, bothequal to one-half the input voltage. The output voltages areboth referenced to Pin 3 (Output Common).

Figure 9. Ultraprecision Voltage Divider

8

7

6

54

3

2

1

C1 150µF

± 0.002%

V+

3V TO 11V

LTC660 • F09

TMIN ≤ TA ≤ TMAX IL ≤ 100nA

C2 150µF

2V+

LTC660+

+

9

LTC660

TYPICAL APPLICATIONS N

U

8

7

6

54

3

2

1

C1 150µF

+VB/2 (4.5V)

LTC1046 • TA10

C2 150µF

OUTPUT COMMON

–VB/2 (–4.5V)

VB (9V)

3V ≤ VB ≤ 11V

LTC660+

+

Figure 10. Battery Splitter

Paralleling for Lower Output Resistance

Additional flexibility of the LTC660 is shown in Figures 11and 12. Figure 11 shows two LTC660s connected inparallel 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 fre-quency will be of more benefit than the paralleling circuitshown.

Stacking for Higher Voltage

Figure 12 makes use of “stacking” two LTC660s to provideeven higher voltages. In Figure 12, a negative voltagedoubler or tripler can be achieved depending upon howPin 8 of the second LTC660 is connected, as shownschematically by the switch.

Figure 12. Stacking for High Voltage

8

7

6

54

3

2

1

150µF

V+

LTC660 • F12

150µF

150µF

VOUT–V+

150µF

FOR VOUT = –2V+FOR VOUT = –3V+

LTC660 1

8

7

6

54

3

2

1

LTC660 2+

+ +

+

8

7

6

54

3

2

1

C1 150µF

V+

LTC660 • F11

8

7

6

54

3

2

1

C1 150µF

C2 150µF

VOUT = –V+

1/4 CD4077

OPTIONAL SYNCHRONIZATION CIRCUIT TO MINIMIZE RIPPLE

LTC660 LTC660+ +

+

Figure 11. Paralleling for 200mA Load Current

10

LTC660

PACKAGE DESCRIPTION

U

Dimensions in inches (millimeters) unless otherwise noted.

N8 Package8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

N8 1197

0.100 ± 0.010 (2.540 ± 0.254)

0.065 (1.651)

TYP

0.045 – 0.065 (1.143 – 1.651)

0.130 ± 0.005 (3.302 ± 0.127)

0.020 (0.508)

MIN0.018 ± 0.003

(0.457 ± 0.076)

0.125 (3.175)

MIN

1 2 3 4

8 7 6 5

0.255 ± 0.015* (6.477 ± 0.381)

0.400* (10.160)

MAX

0.009 – 0.015 (0.229 – 0.381)

0.300 – 0.325 (7.620 – 8.255)

0.325+0.035 –0.015+0.889 –0.3818.255( )

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

11

LTC660

PACKAGE DESCRIPTION

U

Dimensions in inches (millimeters) unless otherwise noted.

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 represen-tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

S8 Package8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

1 2 3 4

0.150 – 0.157** (3.810 – 3.988)

8 7 6 5

0.189 – 0.197* (4.801 – 5.004)

0.228 – 0.244 (5.791 – 6.197)

0.016 – 0.050 0.406 – 1.270

0.010 – 0.020 (0.254 – 0.508)

× 45°

0°– 8° TYP0.008 – 0.010

(0.203 – 0.254)

SO8 0996

0.053 – 0.069 (1.346 – 1.752)

0.014 – 0.019 (0.355 – 0.483)

0.004 – 0.010 (0.101 – 0.254)

0.050 (1.270)

TYPDIMENSION 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

*

**

12

LTC660

LT/GP 0598 2K REV A • PRINTED IN USA

LINEAR TECHNOLOGY CORPORATION 1995

Linear Technology Corporation1630 McCarthy Blvd., Milpitas, CA 95035-7417(408) 432-1900 FAX: (408) 434-0507 www.linear-tech.com

TYPICAL APPLICATIONS N

U

Voltage Inverter

1

2

3

4

8

7

6

5

BOOST

CAP+

GND

CAP–

C2 150µF

LTC660 • F07

C1 150µF

VOUT = –VIN

VIN 1.5V TO 5.5V

LTC660

V+

OSC

LV

VOUT

+

+

Voltage Doubler

1

2

3

4

8

7

6

5

BOOST

CAP+

GND

CAP–

LTC660 • F08

C1 150µF

VOUT = 2VIN

VIN 2.5V

TO 5.5V

LTC660

1N5817*

V+

OSC

LV

VOUT

C2 150µF

* SCHOTTKY DIODE IS FOR START-UP ONLY

++

RELATED PARTSPART NUMBER OUTPUT CURRENT MAXIMUM VIN COMMENTS

Unregulated Output Voltage

LTC660 100mA 6V Highest Current

LTC1046 50mA 6V

LTC1044 20mA 9.5V Lowest Cost

LTC1044A 20mA 13V

LTC1144 20mA 20V Highest Voltage

Regulated Output Voltage

LT1054 100mA 16V Adjustable Output

LTC1262 30mA 6V 12V Fixed Output

LTC1261 10mA 9V – 4V, –4.5V and AdjustableOutputs

All devices are available in plastic 8-lead SO and PDIP packages