Rainbow Electronics MAX660 - Manual (Page 8)

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 cascad-
ed, is defined by V
OUT
= -n (V
IN
).
Paralleling Devices
Paralleling multiple MAX660s reduces the output resis-
tance. 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.
3
4
2
C1n
3
4
8 8
2
5
C1
C2
C2n
+V IN
V OUT
V
OUT
= -nV
IN
5
MAX660
"n"
MAX660
"1"
Figure 3. Cascading MAX660s to Increase Output Voltage
3
4
2
C1n
3
4
8 8
2
5
C1
C2
+V IN
MAX660
"n"
5
R
L
R OUT =
R
OUT
(of MAX660)
n (NUMBER OF DEVICES)
MAX660
"1"
Figure 4. Paralleling MAX660s to Reduce Output Resistance
Manufacturer/
Series
Phone Fax Comments
AVX TPS Series (803) 946-0690 (803) 626-3123
Low-ESR
tantalum SMT
AVX TAG Series (803) 946-0690 (803) 626-3123
Low-cost
tantalum SMT
Matsuo 267 Series (714) 969-2491 (714) 960-6492
Low-cost
tantalum SMT
Sprague 595
Series
(603) 224-1961 (603) 224-1430
Aluminum elec-
trolytic thru-hole
Sanyo MV-GX
Series
(619) 661-6835 (619) 661-1055
Aluminum elec-
trolytic SMT
Sanyo CV-GX
Series
(619) 661-6835 (619) 661-1055
Aluminum elec-
trolytic thru-hole
Nichicon PL
Series
(847) 843-7500 (847) 843-2798
Low-ESR
tantalum SMT
United Chemi-Con
(Marcon)
(847) 696-2000 (847) 696-9278 Ceramic SMT
TDK (847) 390-4373 (847) 390-4428 Ceramic SMT