Rainbow Electronics MAX660 User Manual

MAX660

CMOS Monolithic Voltage Converter

________________________________________________________________ Maxim Integrated Products 1

19-3293; Rev. 2; 9/96

_______________General Description

The MAX660 monolithic, charge-pump voltage inverter
converts a +1.5V to +5.5V input to a corresponding

-1.5V to -5.5V output. Using only two low-cost
capacitors, the charge pump’s 100mA output replaces
switching regulators, eliminating inductors and their
associated cost, size, and EMI. Greater than 90%
efficiency over most of its load-current range combined
with a typical operating current of only 120µA provides
ideal performance for both battery-powered and board­level voltage conversion applications. The MAX660 can
also double the output voltage of an input power supply
or battery, providing +9.35V at 100mA from a +5V
input.

A frequency control (FC) pin selects either 10kHz typ or
80kHz typ (40kHz min) operation to optimize capacitor
size and quiescent current. The oscillator frequency
can also be adjusted with an external capacitor or
driven with an external clock. The MAX660 is a pin­compatible, high-current upgrade of the ICL7660.

The MAX660 is available in both 8-pin DIP and small­outline packages in commercial, extended, and military
temperature ranges.

For 50mA applications, consider the MAX860/MAX861
pin-compatible devices (also available in ultra-small
µMAX packages).

________________________Applications

Laptop Computers

Medical Instruments

Interface Power Supplies

Hand-Held Instruments

Operational-Amplifier Power Supplies

___________________________ Features

♦ Small Capacitors

♦ 0.65V Typ Loss at 100mA Load

♦ Low 120µA Operating Current

♦ 6.5Ω Typ Output Impedance

♦ Guaranteed R

OUT

< 15Ω for C1 = C2 = 10µF

♦ Pin-Compatible High-Current ICL7660 Upgrade

♦ Inverts or Doubles Input Supply Voltage

♦ Selectable Oscillator Frequency: 10kHz/80kHz

♦ 88% Typ Conversion Efficiency at 100mA

(ILto GND)

1

2

3

2

1

3

4

7

8

5

6

8

7

6

5

MAX660

MAX660

FC

CAP+

GND

CAP-

V+

OSC

LV

OUT

FC

CAP+

GND

CAP-

V+

OSC

LV

OUT

C2
1µF to 150µF

VOLTAGE INVERTER

POSITIVE VOLTAGE DOUBLER

+V

IN

1.5V TO 5.5V

INVERTED
NEGATIVE

VOLTAGE

OUTPUT

C1

1µF to 150µF

DOUBLED

POSITIVE

VOLTAGE

OUTPUT

C2
1µF to 150µF

C1

1µF to 150µF

+V

IN

2.5V TO 5.5V
4

_________Typical Operating Circuits

1

2

3

4

8

7

6

5

V+

OSC

LV

OUT

CAP-

GND

CAP+

FC

MAX660

DIP/SO

TOP VIEW

__________________Pin Configuration

______________Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX660CPA 0°C to +70°C 8 Plastic DIP

MAX660CSA 0°C to +70°C 8 SO

MAX660C/D 0°C to +70°C Dice*

MAX660EPA -40°C to +85°C 8 Plastic DIP

MAX660ESA -40°C to +85°C 8 SO

*Contact factory for dice specifications.

MAX660MJA -55°C to +125°C 8 CERDIP

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone]

CONDITIONS

MAX660

CMOS Monolithic Voltage Converter

2 _______________________________________________________________________________________

Supply Voltage (V+ to GND, or GND to OUT) .......................+6V

LV Input Voltage ...............................(OUT - 0.3V) to (V+ + 0.3V)

FC and OSC Input Voltages........................The least negative of

(OUT - 0.3V) or (V+ - 6V) to (V+ + 0.3V)

OUT and V+ Continuous Output Current..........................120mA

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

Continuous Power Dissipation (T

A

= +70°C)

Plastic DIP (derate 9.09mW/°C above + 70°C) ............727mW

SO (derate 5.88mW/°C above +70°C)..........................471mW

CERDIP (derate 8.00mW/°C above +70°C)..................640mW

Operating Temperature Ranges

MAX660C_ _ ........................................................0°C to +70°C

MAX660E_ _ .....................................................-40°C to +85°C

MAX660MJA ...................................................-55°C to +125°C

Storage Temperature Range............................... -65°to +160°C

Lead Temperature (soldering, 10sec) ........................... +300°C

ELECTRICAL CHARACTERISTICS

(V+ = 5V, C1 = C2 = 150µF, test circuit of Figure 1, FC = open, TA = T

MIN

to T

MAX

, unless otherwise noted.) (Note 2)

Stresses beyond those listed under “Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

ABSOLUTE MAXIMUM RATINGS

Note 2: In the test circuit, capacitors C1 and C2 are 150µF, 0.2Ω maximum ESR, aluminum electrolytics.

Capacitors with higher ESR may reduce output voltage and efficiency. See Capacitor Selection section.

Note 3: Specified output resistance is a combination of internal switch resistance and capacitor ESR. See Capacitor Selection section.
Note 4: The ESR of C1 = C2 ≤ 0.5Ω. Guaranteed by correlation, not production tested.

Note 1: OUT may be shorted to GND for 1sec 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.

Doubler, LV = OUT

Inverter, LV = GND

Inverter, LV = open

IL= 100mA to GND

RL= 500Ω connected between OUT and GND

FC = open

TA≤ +85°C

RL= 1kΩ connected between V+ and OUT

FC = V+

TA≤ +85°C, C1 = C2 = 150µF

TA≤ +85°C, C1 = C2 = 10µF, FC = V+ (Note 4)

FC = open, LV = open

FC = V+, LV = open

TA≤ +85°C, OUT more negative than -4V

FC = open

TA> +85°C, OUT more negative than -3.8V

FC = V+

%99.00 99.96No load

Voltage-Conversion
Efficiency

%

88

Power Efficiency

92 96

96 98

±8

OSC Input Current µA

±1

kHz

40 80

Oscillator Frequency

2.5 5.5

1.5 5.5

V

3.0 5.5

RL= 1kΩ

Operating Supply Voltage

510

12

6.5 10.0

Ω

15

IL= 100mAOutput Resistance (Note 3)

mA

0.12 0.5

No loadSupply Current

13

100

mA

100

Output Current

UNITSMIN TYP MAXPARAMETER

MAX660

CMOS Monolithic Voltage Converter

_________________________________________________________________________________________________ 3

OUTPUT

VOLTAGE

DROP

FROM

SUPPLY

(V)

__________________________________________Typical Operating Characteristics

-4.0

0.1 10 100

OUTPUT VOLTAGE

vs. OSCILLATOR FREQUENCY

-3.5

-5.0

OSCILLATOR FREQUENCY (kHz)

OUTPUT VOLTAGE (V)

1

-4.5

-3.0

I

LOAD

= 1mA

I

LOAD

= 80mA

MAX660-5

I

LOAD

= 10mA

Figure 1. MAX660 Test Circuit

All curves are generated using the test circuit of Figure 1
with V+ =5V, LV = GND, FC = open, and TA= +25°C,
unless otherwise noted. The charge-pump frequency is
one-half the oscillator frequency. Test results are also
valid for doubler mode with GND = +5V, LV = OUT, and
OUT = 0V, unless otherwise noted; however, the input
voltage is restricted to +2.5V to +5.5V.

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

400

350

300

250

200

150

SUPPLY CURRENT (µA)

100

50

0

2.0 3.0 4.0 5.0

1.5 2.5 4.5 5.5
SUPPLY VOLTAGE (V)

LV = OPEN

3.5

LV = OUT

LV = GND

10

MAX660-1

1

0.1

SUPPLY CURRENT (mA)

0.01

0.1 10 100

SUPPLY CURRENT

vs. OSCILLATOR FREQUENCY

1

OSCILLATOR FREQUENCY (kHz)

V+

C1

1

FC

2

CAP+

3

MAX660

GND

4

CAP-

V+

OSC

LV

OUT

-3.0

MAX660-4

-3.4

-3.8

-4.2

OUTPUT VOLTAGE (V)

-4.6

-5.0
0 20 60 100

8

7

6

5

OUTPUT VOLTAGE AND EFFICIENCY

vs. LOAD CURRENT, V+ = 5V

I

S

I

L

C2

ICL7660

EFF.

V

OUT

ICL7660

40 80

LOAD CURRENT (mA)

V+
(+5V )

R

L

MAX660

MAX660

V

OUT

100

MAX660-6A

92

84

76

EFFICIENCY (%)

68

60

EFFICIENCY vs. LOAD CURRENT

100

92

84

76

EFFICIENCY (%)

68

60

0 20 60 100

OUTPUT VOLTAGE DROP

vs. LOAD CURRENT

1.2

V+ = 3.5V

V+ = 1.5V

V+ = 2.5V

40 80

LOAD CURRENT (mA)

V+ = 5.5V

V+ = 4.5V

MAX660-2

1.0

0.8

0.6

0.4

0.2

0

0 100

20 40 80

10 30 50 70 90

V+ = 1.5V

V+ = 5.5V

60

LOAD CURRENT (mA)

MAX660-3

V+ = 2.5V

V+ = 3.5V

V+ = 4.5V

MAX660

CMOS Monolithic Voltage Converter

4 _______________________________________________________________________________________

0

(°C)

MAX660

11

_____________________________Typical Operating Characteristics (continued)

30

0

-60 140

OUTPUT SOURCE RESISTANCE

vs. TEMPERATURE

5

25

TEMPERATURE (°C)

OUTPUT SOURCE RESISTANCE (Ω)

0

15

10

-40 -20 20

20

40 60 80 100 120

C1, C2 = 150

µF OS-CON CAPACITORS

R

L

= 100Ω

V+ = 5.0V

V+ = 1.5V

V+ = 3.0V

MAX660-12

OSCILLATOR FREQUENCY

OSCILLATOR FREQUENCY

vs. SUPPLY VOLTAGE

vs. SUPPLY VOLTAGE

LV = GND

LV = GND

FC = V+, OSC = OPEN

FC = V+, OSC = OPEN

1.0

1.5 2.0 4.0

1.0

2.5 3.0 4.5 5.0 5.5

1.5 2.0 4.0

2.5 3.0 4.5 5.0 5.

SUPPLY VOLTAGE (V)

OSCILLATOR FREQUENCY

vs. TEMPERATURE

FC = V+, OSC = OPEN, RL = 100

LV = OPEN

LV = OPEN

3.5

3.5

OSCILLATOR FREQUENCY

vs. SUPPLY VOLTAGE

12

MAX660-7

10

8

6

4

OSCILLATOR FREQUENCY (kHz)

2

0

1.5 5.5

LV = GND

LV = OPEN

FC = OPEN, OSC = OPEN

2.5 3.5
SUPPLY VOLTAGE (V)

OSCILLATOR FREQUENCY

vs. TEMPERATURE

12

MAX660-10

10

Ω

8

6

4

OSCILLATOR FREQUENCY (kHz)

2

FC = OPEN, OSC = OPEN

= 100Ω

R

L

100

96

92

88

84

80

76

EFFICIENCY (%)

72

68

64

60

vs. OSCILLATOR FREQUENCY

I

I

= 10mA

LOAD

0.1 10 100
OSCILLATOR FREQUENCY (kHz)

OSCILLATOR FREQUENCY

vs. EXTERNAL CAPACITANCE

100

10

1

0.1

OSCILLATOR FREQUENCY (kHz)

EFFICIENCY

= 1mA

LOAD

I

LOAD

1

FC = V+

FC = OPEN

= 80mA

100

100

MAX660-6

80

80

60

60

40

40

20

OSCILLATOR FREQUENCY (kHz)

20

OSCILLATOR FREQUENCY (kHz)

0

0

100

MAX660-9

80

60

40

20

OSCILLATOR FREQUENCY (kHz)

MAX660-8

4.5

MAX660-10A

0.01
1 100

OUTPUT SOURCE RESISTANCE

vs. SUPPLY VOLTAGE

14

12

10

8

6

4

OUTPUT SOURCE RESISTANCE (Ω)

2

0

1.5 2.5 4.5

2.0 3.0 4.0 5.55.0

10 1000

CAPACITANCE (pF)

3.5

SUPPLY VOLTAGE (V)

1000

MAX660-13

0

-60 140

-40 -20 100

0

20 40 60 80 120

TEMPERATURE (°C)

OUTPUT SOURCE RESISTANCE

vs. TEMPERATURE

30

25

20

15

10

OUTPUT SOURCE RESISTANCE (Ω)

5

0

C1, C2 = 150

ELECTROLYTIC

R

-60 140

-40 -20 20

= 100Ω

L

0

TEMPERATURE

µF ALUMINUM

CAPACITORS

V+ = 1.5V

40 60 80 100 120

V+ = 3.0V

V+ = 5.0V

0

-60 140

-

0 20 100

-40 -20 40 60 120
TEMPERATURE (°C)

80

NAME

MAX660

CMOS Monolithic Voltage Converter

_______________________________________________________________________________________ 5

______________________________________________________________Pin Description

NAME

Positive Voltage Output

Same as Inverter; however, do not over­drive OSC in voltage-doubling mode.

LV must be tied to OUT for all input
voltages.

Power-Supply Ground Input

Same as Inverter

Power-Supply Positive Voltage Input

Same as Inverter

Same as Inverter

Oscillator Control Input. OSC is connected to an internal
15pF capacitor. An external capacitor can be added to slow
the oscillator. Take care to minimize stray capacitance. An
external oscillator may also be connected to overdrive OSC.

Low-Voltage Operation Input. Tie LV to GND when input
voltage is less than 3V. Above 3V, LV may be connected to
GND or left open; when overdriving OSC, LV must be
connected to GND.

Output, Negative Voltage

Charge-Pump Capacitor, Negative Terminal

Power-Supply Ground Input

Frequency Control for internal oscillator, FC = open,
f

OSC

= 10kHz typ; FC = V+, f

OSC

= 80kHz typ (40kHz min),

FC has no effect when OSC pin is driven externally.

PIN

V+

OSC

LV

OUT

CAP-

GND

CAP+

FC

Power-Supply Positive Voltage Input8

7

6

5

4

3

Charge-Pump Capacitor, Positive Terminal2

1

FUNCTION

DOUBLERINVERTER

OUTPUT CURRENT vs. CAPACITANCE:

= +4.5V, V

V

FC = V+
OSC = OPEN

0.33 1.0 2.0

IN

2.2 104.7 22 47 100 220

CAPACITANCE (µF)

120

100

80

60

40

CURRENT (mA)

20

0

OUTPUT CURRENT vs. CAPACITANCE:

= +3.0V, V

V

60

50

40

30

20

CURRENT (mA)

10

0

IN

FC = V+
OSC = OPEN

0.33 1.0 2.0

2.2 104.7 22 47 100 220

CAPACITANCE (µF)

OUT

OUT

= -4V

= -2.7V

MAX660 CHART -01

MAX660 CHART -03

OUTPUT CURRENT vs. CAPACITANCE:

= +4.5V, V

V

250

200

150

100

CURRENT (mA)

50

0

IN

FC = V+
OSC = OPEN

0.33 1.0 2.0

2.2 104.7 22 47 100 220

CAPACITANCE (µF)

OUTPUT CURRENT vs. CAPACITANCE:

= +3.0V, V

V

120

100

80

60

40

CURRENT (mA)

20

0

IN

FC = V+
OSC = OPEN

0.33 1.0 2.0

2.2 104.7 22 47 100 220

CAPACITANCE (µF)

OUT

OUT

= -3.5V

= -2.4V

MAX660 CHART -02

MAX660 CHART -04

MAX660

CMOS Monolithic Voltage Converter

6 _______________________________________________________________________________________

______________Detailed Description

The MAX660 capacitive charge-pump circuit either
inverts or doubles the input voltage (see Typical
Operating Circuits). For highest performance, low
effective series resistance (ESR) capacitors should be
used. See Capacitor Selection section for more details.

When using the inverting mode with a supply voltage
less than 3V, LV must be connected to GND. This
bypasses the internal regulator circuitry and provides
best performance in low-voltage applications. When
using the inverter mode with a supply voltage above
3V, LV may be connected to GND or left open. The part
is typically operated with LV grounded, but since LV
may be left open, the substitution of the MAX660 for the
ICL7660 is simplified. LV must be grounded when over­driving OSC (see Changing Oscillator Frequency sec-
tion). Connect LV to OUT (for any supply voltage) when
using the doubling mode.

__________Applications Information

Negative Voltage Converter

The most common application of the MAX660 is as a
charge-pump voltage inverter. The operating circuit
uses only two external capacitors, C1 and C2 (see
Typical Operating Circuits).

Even though its output is not actively regulated, the
MAX660 is very insensitive to load current changes. A
typical output source resistance of 6.5Ω means that
with an input of +5V the output voltage is -5V under
light load, and decreases only to -4.35V with a load of
100mA. Output source resistance vs. temperature and
supply voltage are shown in the Typical Operating
Characteristics graphs.

Output ripple voltage is calculated by noting the output
current supplied is solely from capacitor C2 during

one-half of the charge-pump cycle. This introduces a
peak-to-peak ripple of:

V

RIPPLE

= I

OUT

+ I

OUT

(ESRC2)

2(f

PUMP

) (C2)

For a nominal f

PUMP

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. If C2 is raised to 390µF, the ripple
drops to 45mV.

Positive Voltage Doubler

The MAX660 operates in the voltage-doubling mode as
shown in the Typical Operating Circuit. The no-load
output is 2 x VIN.

Other Switched-Capacitor Converters

Please refer to Table 1, which shows Maxim’s charge­pump offerings.

Changing Oscillator Frequency

Four modes control the MAX660’s clock frequency, as
listed below:

FC OSC Oscillator Frequency

Open Open 10kHz

FC = V+ Open 80kHz

Open or External See Typical Operating
FC = V+ Capacitor Characteristics

Open External External Clock Frequency

Clock

When FC and OSC are unconnected (open), the oscil­lator runs at 10kHz typically. When FC is connected to
V+, the charge and discharge current at OSC changes
from 1.0µA to 8.0µA, thus increasing the oscillator

MAX829 MAX861 MAX1044

Package SOT 23-5

SO-8,

µMAX

SO-8,
µMAX

Op. Current
(typ, mA)

0.15

0.3 at 13kHz,

1.1 at 100kHz,

2.5 at 250kHz

0.03

Output Ω
(typ)

20 12 6.5

Pump Rate
(kHz)

35 13, 100, 150 5

Input (V) 1.25 to 5.5 1.5 to 5.5 1.5 to 10

ICL7662

SO-8

0.25

125

10

1.5 to 10

MAX660

SO-8

0.12 at 5kHz,
1 at 40kHz

6.5

5, 40

1.5 to 5.5

MAX860

SO-8,
µMAX

0.2 at 6kHz,

0.6 at 50kHz,

1.4 at 130kHz

12

6, 50, 130

1.5 to 5.5

MAX828

SOT 23-5

0.06

20

12

1.25 to 5.5

ICL7660

SO-8,
µMAX

0.08

55

10

1.5 to 10

Table 1. Single-Output Charge Pumps

MAX660

CMOS Monolithic Voltage Converter

_______________________________________________________________________________________ 7

frequency eight times. In the third mode, the oscillator
frequency is lowered by connecting a capacitor
between OSC and GND. FC can still multiply the fre­quency by eight times in this mode, but for a lower
range of frequencies (see Typical Operating
Characteristics).

In the inverter mode, OSC may also be overdriven by an
external clock source that swings within 100mV of V+
and GND. Any standard CMOS logic output is suitable
for driving OSC. When OSC is overdriven, FC has no
effect. Also, LV must be grounded when overdriving
OSC. Do not overdrive OSC in voltage-doubling mode.

Note: In all modes, the frequency of the signal appear­ing at CAP+ and CAP- is one-half that of the oscillator.
Also, an undesirable effect of lowering the oscillator fre­quency is that the effective output resistance of the
charge pump increases. This can be compensated by
increasing the value of the charge-pump capacitors
(see Capacitor Selection section and Typical Operating
Characteristics).

In some applications, the 5kHz output ripple frequency
may be low enough to interfere with other circuitry. If
desired, the oscillator frequency can then be increased
through use of the FC pin or an external oscillator as
described above. The output ripple frequency is one­half the selected oscillator frequency. Increasing the
clock frequency increases the MAX660’s quiescent
current, but also allows smaller capacitance values to
be used for C1 and C2.

________________Capacitor Selection

Three factors (in addition to load current) affect the
MAX660 output voltage drop from its ideal value:

1) MAX660 output resistance

2) Pump (C1) and reservoir (C2) capacitor ESRs

3) C1 and C2 capacitance

The voltage drop caused by MAX660 output resistance
is the load current times the output resistance.
Similarly, the loss in C2 is the load current times C2’s
ESR. The loss in C1, however, is larger because it
handles currents that are greater than the load current
during charge-pump operation. The voltage drop due
to C1 is therefore about four times C1’s ESR multiplied
by the load current. Consequently, a low (or high) ESR
capacitor has a much greater impact on performance
for C1 than for C2.

Generally, as the pump frequency of the MAX660
increases, the capacitance values required to maintain
comparable ripple and output resistance diminish pro­portionately. The curves of Figure 2 show the total circuit

output resistance for various capacitor values (the pump
and reservoir capacitors’ values are equal) and oscillator
frequencies. These curves assume 0.25Ω capacitor ESR
and a 5.25Ω MAX660 output resistance, which is why
the flat portion of the curve shows a 6.5Ω (R

O

MAX660 +
4 (ESRC1) + ESRC2) effective output resistance. Note:
RO= 5.25Ω is used, rather than the typical 6.5Ω,
because the typical specification includes the effect of
the ESRs of the capacitors in the test circuit.

In addition to the curves in Figure 2, four bar graphs in
the Typical Operating Characteristics show output cur­rent for capacitances ranging from 0.33µF to 220µF.
Output current is plotted for inputs of 4.5V (5V-10%) and

3.0V (3.3V-10%), and allow for 10% and 20% output
droop with each input voltage. As can be seen from the
graphs, the MAX660 6.5Ω series resistance limits
increases in output current vs. capacitance for values
much above 47µF. Larger values may still be useful,
however, to reduce ripple.

To reduce the output ripple caused by the charge
pump, increase the reservoir capacitor C2 and/or
reduce its ESR. Also, the reservoir capacitor must have
low ESR if filtering high-frequency noise at the output is
important.

Not all manufacturers guarantee capacitor ESR in the
range required by the MAX660. In general, capacitor ESR
is inversely proportional to physical size, so larger capaci­tance values and higher voltage ratings tend to reduce
ESR.

Figure 2. Total Output Source Resistance vs. C1 and C2
Capacitance (C1 = C2)

100kHz

20

)

Ω

18

16

14

12

10

8

6

4

2

TOTAL OUTPUT SOURCE RESISTANCE (

0

50kHz

2 4 6 8 10 100 1000

1

10kHz

20kHz

5kHz

2kHz

CAPACITANCE (µF)

1kHz

MAX660-fig 2

ESR = 0.25Ω
FOR BOTH
C1 AND C2

MAX660 OUTPUT
SOURCE RESISTANCE
ASSUMED TO BE

5.25Ω

MAX660

CMOS Monolithic Voltage Converter

8 _______________________________________________________________________________________

The following is a list of manufacturers who provide
low-ESR electrolytic capacitors:

Cascading Devices

To produce larger negative multiplication of the initial
supply voltage, the MAX660 may be cascaded as
shown in Figure 3. The resulting output resistance is
approximately equal to the sum of the individual
MAX660 R

OUT

values. The output voltage, where n is
an integer representing the number of devices cascad­ed, is defined by V

OUT

= -n (VIN).

Paralleling Devices

Paralleling multiple MAX660s reduces the output resis­tance. As illustrated in Figure 4, each device requires
its own pump capacitor C1, but the reservoir capacitor
C2 serves all devices. The value of C2 should be
increased by a factor of n, where n is the number of
devices. Figure 4 shows the equation for calculating
output resistance.

Figure 3. Cascading MAX660s to Increase Output Voltage

Figure 4. Paralleling MAX660s to Reduce Output Resistance

Manufacturer/

Series

Phone Fax Comments

AVX TPS Series [phone] [phone]

Low-ESR
tantalum SMT

AVX TAG Series [phone] [phone]

Low-cost
tantalum SMT

Matsuo 267 Series [phone] [phone]

Low-cost
tantalum SMT

Sprague 595
Series

[phone] [phone]

Aluminum elec­trolytic thru-hole

Sanyo MV-GX
Series

[phone] [phone]

Aluminum elec­trolytic SMT

Sanyo CV-GX
Series

[phone] [phone]

Aluminum elec­trolytic thru-hole

Nichicon PL
Series

[phone] [phone]

Low-ESR
tantalum SMT

United Chemi-Con
(Marcon)

[phone] [phone] Ceramic SMT

TDK [phone] [phone] Ceramic SMT

R

(of MAX660)

R

OUT

OUT

=

n (NUMBER OF DEVICES)

+V

+V

IN

2

MAX660

C1

3

"1"

4

88

C1n

5

2

MAX660

3

"n"

4

V

C2

OUT

= -nV

5

C2n

IN

2

MAX660

C1

V

OUT

3

"1"

4

8

C1n

5

IN

2

MAX660

3

4

"n"

8

R

L

5

C2

Combined Positive Supply Multiplication

and Negative Voltage Conversion

This dual function is illustrated in Figure 5. In this cir­cuit, capacitors C1 and C3 perform the pump and
reservoir functions respectively for generation of the
negative voltage. Capacitors C2 and C4 are respec­tively pump and reservoir for the multiplied positive
voltage. This circuit configuration, however, leads to
higher source impedances of the generated supplies.
This is due to the finite impedance of the common
charge-pump driver.

MAX660

CMOS Monolithic Voltage Converter

_______________________________________________________________________________________ 9

Figure 5. Combined Positive Multiplier and Negative Converter

Figure 6. MAX660 generates a +5V regulated output from a 3V
lithium battery and operates for 16 hours with a 40mA load.

+V

IN

8

D1, D2 = 1N4148

2

MAX660

3

C1

4

C3

5

6

D1

V

= -V

OUT

IN

C2

D2

V

= (2VIN) -

OUT

) - (V

FD2

)

(V

FD1

C4

1M

3V LITHIUM BATTERY
DURACELL DL123A

3

2

8

MAX660

150

4

150µF

54

NOTE: ALL 150µF CAPACITORS ARE MAXC001, AVAILABLE FROM MAXIM.

6

µF

LBI

8

IN OUT

MAX667

GND SHDN

1M

OPEN-DRAIN
LOW-BATTERY OUTPUT

5V/100mA

620k

1M

220k

LBO

DD

SET

2

7

1

6

5

150µF

MAX660

CMOS Monolithic Voltage Converter

10 ______________________________________________________________________________________

___________________Chip Topography

TRANSISTOR COUNT = 89

SUBSTRATE CONNECTED TO V+.

FC

CAP+

V+

GND

OSC

LV

CAP-

OUT

0.073"

(1.85mm)

0.120"

(3.05mm)

MAX660

CMOS Monolithic Voltage Converter

______________________________________________________________________________________ 11

________________________________________________________Package Information

INCHES MILLIMETERS

MIN

0.015

0.125

0.055

0.016

0.045

0.008

0.005

0.300

0.240

0.100

0.300

0.115

PINS

8
14
16
18
20
24

MAX

0.200

–

0.175

0.080

0.022

0.065

0.012

0.080

0.325

0.310

0.400

–

0.150

INCHES MILLIMETERS

MIN

0.348

0.735

0.745

0.885

1.015

1.14

–

–
–

0.390

0.765

0.765

0.915

1.045

1.265

MAX

MIN

–

0.38

3.18

1.40

0.41

1.14

0.20

0.13

7.62

6.10

2.54

7.62
–

2.92

MIN

8.84

18.67

18.92

22.48

25.78

28.96

MAX

5.08
–

4.45

2.03

0.56

1.65

0.30

2.03

8.26

7.87
–
–

10.16

3.81

MAX

9.91

19.43

19.43

23.24

26.54

32.13

21-0043A

PKG.

P
P
P
P
P
N

DIM

A
A1
A2
A3

B
B1

C
D1

E
E1

e
eA
eB

L

DIM

D
D
D
D
D
D

E

D

E1

A3

A2

A

L

A1

e

B1

B

0° - 15°

C

eA

eB

D1

Plastic DIP

PLASTIC

DUAL-IN-LINE

PACKAGE

(0.300 in.)

DIM

D

A

0.101mm

e

A1

B

0.004in.

C

L

0°-8°

Narrow SO

HE

SMALL-OUTLINE

PACKAGE

(0.150 in.)

A
A1

B

C

E

e

H

L

DIM

D
D
D

INCHES MILLIMETERS

MIN

0.053

0.004

0.014

0.007

0.150

0.228

0.016

PINS

8
14
16

MAX

0.069

0.010

0.019

0.010

0.157

0.244

0.050

INCHES MILLIMETERS

MIN

0.189

0.337

0.386

MAX

0.197

0.344

0.394

MIN

1.35

0.10

0.35

0.19

3.80

5.80

0.40

MIN

4.80

8.55

9.80

MAX

1.75

0.25

0.49

0.25

4.00

1.270.050

6.20

1.27

MAX

5.00

8.75

10.00

21-0041A

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

12 ____________________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

MAX660

CMOS Monolithic Voltage Converter

___________________________________________Package Information (continued)

INCHES MILLIMETERS

MIN

0.014

0.038

0.008

0.220

0.290
e
L

0.125

0.150

0.015

0.005

PINS

8
14
16
18
20
24

MAX

–

0.200

0.023

0.065

0.015

0.310

0.320

0.200

–

0.070

–

0.098

–

INCHES MILLIMETERS

MIN

MAX

–

0.405

–

0.785

–

0.840

–

0.960

–

1.060

–

1.280

MIN

–

0.36

0.97

0.20

5.59

7.37

3.18

3.81

0.38

–

0.13

MIN

–
–
–
–
–
–

A

Q

L

DIM

E1

D

E

0°-15°

e

B1

L1

C

B

S1

S

CERDIP

CERAMIC DUAL-IN-LINE

PACKAGE

(0.300 in.)

A
B

B1

C
E

E1

L1

Q
S

S1

DIM

D
D
D
D
D
D

MAX

5.08

0.58

1.65

0.38

7.87

8.13

2.54 0.100

5.08

–

1.78

2.49

–

MAX

10.29

19.94

21.34

24.38

26.92

32.51

21-0045A