MAX1044 Datasheet, PDF (11/12 Pages) Maxim Integrated Products – Switched-Capacitor Voltage Converters

Switched-Capacitor Voltage Converters
1
8
2
MAX1044
7
C1
ICL7660
3
6
4
5
1
1
8
2
MAX1044
7
C1
ICL7660
3
6
4
5
n
V+
V_OUT = -(V+)
C2
Paralleling Devices
Paralleling multiple MAX1044/ICL7660s reduces output
resistance and increases current capability. As illus-
trated 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:
R _OUT
=
R_OUT(of MAX1044 or ICL7660)
n (number of devices)
Shutdown Schemes
Figures 14a–14c illustrate three ways of adding shut-
down capability to the MAX1044/ICL7660. When using
these circuits, be aware that the additional capacitive
loading on the OSC pin will reduce the oscillator fre-
quency. 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 13. Paralleling MAX1044/ICL7660 to Reduce Output
Resistance
1
2
MAX1044
ICL7660
10µF
3
4
a)
MAX1044 ₇
ICL7660
V+
10kΩ REQUIRED FOR TTL
8
1N4148
V+ _{CMOS or}
TTL GATE
7
6
5
VOUT = -(V+)
10µF
V+
74HC03
OPEN-DRAIN OR
74LS03
OPEN-COLLECTOR
NAND GATES
b)
MAX1044 ₇
ICL7660
V+
OUTPUT
ENABLE
74HC126 OR
74LS126
TRI-STATE BUFFER
c)
Figure 14a-14c. Shutdown Schemes for MAX1044/ICL7660
_Ordering Information (continued)
PART
MAX1044ESA
MAX1044MJA
ICL7660CPA
ICL7660CSA
ICL7660CUA
ICL7660C/D
ICL7660EPA
ICL7660ESA
ICL7660AMJA^†
ICL7660AMTV^†
TEMP. RANGE
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
-55°C to +125°C
PIN-PACKAGE
8 SO
8 CERDIP**
8 Plastic DIP
8 SO
8 µMAX
Dice*
8 Plastic DIP
8 SO
8 CERDIP**
8 TO-99**
* Contact factory for dice specifications.
** Contact factory for availability.
† _{The Maxim ICL7660 meets or exceeds all “A” and “S”}
specifications.
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