Datasheet

Efficiency
Efficiency(%)=V /(2 V ) 100
(step-upoperatingmode)
or
(step-downoperatingmode)
OUT IN
´ ´
V
V
OUT
IN
´ 100
Layout
V
ENABLE
V
IN
C
IN
GND
C
P
V
OUT
C
OUT
AREA:<0.08sq.inches
REG71055-Q1
SBAS477 – JULY 2009 ....................................................................................................................................................................................................... www.ti.com
The efficiency of the charge pump regulator varies with the output voltage version, the applied input voltage, the
load current, and the internal operation mode of the device.
The approximate efficiency is given by:
Table 2 lists the approximate values of the input voltage at which the device changes internal operating mode.
See efficiency curves in the Typical Characteristics section for various loads and input voltages.
Table 2. Operating Mode Change vs V
IN
PRODUCT OPERATING MODE CHANGES AT V
IN
OF
REG71055 Step-up only
Large transient currents flow in the V
IN
, V
OUT
, and GND traces. To minimize both input and output ripple, keep
the capacitors as close as possible to the regulator using short, direct circuit traces.
A suggested printed circuit board (PCB) routing is shown in Figure 11 . The trace lengths from the input and
output capacitors have been kept as short as possible.
Figure 11. Suggested PCB Design for Minimum Ripple
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Product Folder Link(s): REG71055-Q1