Paralleling Devices

Paralleling multiple MAX1044/ICL7660s reduces output

resistance and increases current capability. As illustrated

in Figure 13, each device requires its own pump capacitor

C1, but the reservoir capacitor C2 serves all devices. The

equation for calculating output resistance is:

OUT

OUT

R

(of MAX1044 or ICL7660)

R

n (number of devices)

=

Shutdown Schemes

Figures 14a–14c illustrate three ways of adding shutdown

capability to the MAX1044/ICL7660. When using these

circuits, be aware that the additional capacitive loading

on the OSC pin will reduce the oscillator frequency. The

first circuit has the least loading on the OSC pin and has

the added advantage of controlling shutdown with a high

or low logic level, depending on the orientation of the

switching diode.

Figure 14a-14c. Shutdown Schemes for MAX1044/ICL7660

Figure 13. Paralleling MAX1044/ICL7660 to Reduce Output

Resistance

*Contact factory for dice specifications. Dice are not tested

**Contact factory for availability.

†The Maxim ICL7660 meets or exceeds all “A” and “S”

specifications.

MAX1044

ICL7660

+

4

3

VOUT = -(V+)

2

1

5

6

7

8

C2

C1

V+

MAX1044

ICL7660

4

3

2

1

5

6

7

8

C1

1

n

+

MAX1044

ICL7660

+

4

3

10µF

VOUT = -(V+)

10µF

CMOS or

TTL GATE

1N4148

V+

2

1

5

6

7

8

V+

10kΩ REQUIRED FOR TTL

74HC03

OPEN-DRAIN OR

74LS03

OPEN-COLLECTOR

NAND GATES

a)

b)

c)

V+

MAX1044

ICL7660

7

OUTPUT

ENABLE

74HC126 OR

74LS126

TRI-STATE BUFFER

V+

7

MAX1044

ICL7660

PART

TEMP. RANGE

PIN-PACKAGE

MAX1044CPA

0°C to +70°C

8 Plastic DIP

MAX1044CSA

0°C to +70°C

8 SO

MAX1044C/D*

0°C to +70°C

Dice*

MAX1044EPA

-40°C to +85°C

8 Plastic DIP

MAX1044ESA

-40°C to +85°C

8 SO

MAX1044MJA

-55°C to +125°C

8 CERDIP**

ICL7660CPA

0°C to +70°C

8 Plastic DIP

ICL7660CSA

0°C to +70°C

8 SO

ICL7660CUA

0°C to +70°C

8 μMAX

ICL7660C/D

0°C to +70°C

Dice*

ICL7660EPA

-40°C to +85°C

8 Plastic DIP

ICL7660ESA

-40°C to +85°C

8 SO

ICL7660AMJA†

-55°C to +125°C

8 CERDIP**

ICL7660AMTV†

-55°C to +125°C

8 TO-99**

Ordering Information

MAX1044/ICL7660

Switched-Capacitor Voltage Converters

www.maximintegrated.com

Maxim Integrated │ 12