MAX864 Maxim, MAX864 Datasheet - Page 8

• Manufacturer Part Number: MAX864
• Description: Dual-Output Charge Pump with Shutdown
• Manufacturer: Maxim

Dual-Output Charge Pump with Shutdown
The most common application of the MAX864 is as a
dual charge-pump voltage converter that provides pos-
itive and negative outputs of two times a positive input
voltage for biasing analog circuitry (Figure 3). Select a
charge-pump frequency high enough so it does not
interfere with other circuitry, but low enough to maintain
low supply current. See Table 1 for the correct device
configuration.
Figure 3. Positive and Negative Converter
8
__________Applications Information
_______________________________________________________________________________________
Positive and Negative Converter
SEE TABLE 1
(+1.75V TO +6.0V)
C2
V
IN
IN
1
2
3
4
5
6
7
8
C1-
C2+
GND
C2-
V-
SHDN
FC1
FC0
MAX864
C1
GND
N.C.
N.C.
N.C.
N.C.
C1+
V+
IN
Paralleling multiple MAX864s reduces the output resis-
tance of both the positive and negative converters
(Figure 4). The effective output resistance is the output
resistance of one device divided by the total number of
devices. Separate C1 and C2 charge-pump capacitors
are required for each MAX864, but the reservoir capac-
itors C3 and C4 can be shared.
16
14
13
15
12
11
10
9
C3
C4
+2 x V
-2 x V
IN
IN
Paralleling Devices