Rainbow Electronics MAX864 - Manual (Page 9)

MAX864
Dual-Output Charge Pump with Shutdown
_______________________________________________________________________________________ 9
Heavy Output Current Loads
When under heavy loads, where V+ is sourcing current
into V- (i.e., load current flows from V+ to V-, rather than
from supply to ground), do not allow the V- supply to
pull above ground. In applications where large currents
flow from V+ to V-, use a Schottky diode (1N5817)
between GND and V-, with the anode connected to
GND (Figure 5).
Layout and Grounding
Good layout is important, primarily for good noise per-
formance. To ensure good layout, mount all compo-
nents as close together as possible, keep traces short
to minimize parasitic inductance and capacitance, and
use a ground plane. Connecting all N.C. pins to a
ground plane improves thermal dissipation.
MAX864
V+
1
2
3
4
C1-
GND
3.3 µ F
3.3 µ F
3.3 µ F 3.3 µ F
3.3 µ F 3.3 µ F
V+ OUT
V IN
V- OUT
8
7
6
5
C2+
C2-
V-
C1+
IN
GND
MAX864
V+
1
2
3
4
C1-
8
7
6
5
C2+
C2-
V IN
V-
C1+
IN
GND
Figure 4. Paralleling Two MAX864s
MAX864
GND
11
5
V-
Figure 5. High V- Load Circuit