MAX828, MAX829
http://onsemi.com
13
A 3.0 1N4148
B 3.0 MBRA120E
Curve V
in
(V) Diodes
110
96.5
MAX828
R
out
(W)
C 5.0 1N4148
D 5.0 MBRA120E
84.5
78.2
111
96.7
MAX829
R
out
(W)
87.3
77.1
+
5
4
2
3
1
OSC
MAX828 Capacitors = 10 F
MAX829 Capacitors = 3.3 F
V
in
5
4
2
3
1
OSC
+
−V
out
+
+
Figure 42. Paralleling Devices for Increased Negative Output Current
An increase in converter output current capability with a reduction in output resistance can be obtained by paralleling two
or more devices. The output current capability is approximately equal to the number of devices paralleled. A single shared
output capacitor is sufficient for proper operation but each device does require it’s own pump capacitor. Note that the output
ripple frequency will be complex since the oscillators are not synchronized. The output resistance is approximately equal to
the output resistance of one device divided by the total number of devices paralleled. The performance characteristics for a
converter consisting of two paralleled devices is shown below.
0
−2.0
4020
−3.0
−4.0
−5.0
80 100
I
out
, OUTPUT CURRENT (mA)
V
out
, OUTPUT VOLTAGE (V)
60
Figure 43. Parallel Load Regulation, Output
Voltage vs. Output Current MAX828
A
B
0
−2.0
4020
−3.0
−4.0
−5.0
80 10
I
out
, OUTPUT CURRENT (mA)
V
out
, OUTPUT VOLTAGE (V)
60
Figure 44. Parallel Load Regulation, Output
Voltage vs. Output Current MAX829
C
D
T
A
= 25°C T
A
= 25°C