MAX711ESE Maxim Integrated Products, MAX711ESE Datasheet - Page 8

• Manufacturer Part Number: MAX711ESE
• Description: DC/DC Switching Converters 3.3/5V or Adjustable Step-Up Step-Down
• Manufacturer: Maxim Integrated Products

In high-efficiency mode
input voltage is limited to 7V. This voltage limitation is
easily overcome, however, by configuring the LBO out-
put to change modes based on input voltage, allowing
an 11V maximum input with high-efficiency configura-
tions. Four operating configurations are described in
Table 1 and in the following subsections.
3.3V/5V or Adjustable,
Step-Up/Down DC-DC Converters
Table 1. Operating Configurations
Figure 2a. High-Efficiency Operating Configuration for
V
8
100 F
BATT
NO.
1
2
3
4
V
_______________________________________________________________________________________
IN
= +1.8V TO +11V
< V
High efficiency,
7V max V
High efficiency,
V
(Figure 2a)
High efficiency,
11V, V
(Figure 2b)
Low noise
OUT
DESCRIPTION
BATT
0.1 F
BATT
< V
SHDN
STBY
N/E
LBO
LBI+
LBI-
REF
IN
OUT
< 6.5V
PGND
MAX710
GND
(N/E = low), the maximum
VOLTAGE
Up to 7V
Up to 11V
Up to 11V
Up to 11V
INPUT
ILIM
OUT
3/5
PS
LX
CONNECTIONS
N/E = GND
LBO = N/E
LBI- = V
LBI+ = V
LBO = N/E
LBI- = REF
LBI+ = R5, R6
N/E = PS
L1
4.7 F
OUT
IN
100 F
With N/E connected to GND, when the IC boosts, the
linear regulator operates only as a switch, with mini-
mum forward drop, until V
lation begins). This configuration is limited to no more
than 7V input, but provides best efficiency for battery-
only operation or low-voltage AC adapter usage.
In this configuration, N/E is driven high by LBO when
V
boosts, and the linear regulator operates as a switch,
with minimum forward drop. When V
ear regulator operates with V
increases by V
is set inside the IC to approximately 0.5V (at 5V V
When V
efficiency is poorer than in configuration 1, so configu-
ration 2 is most suitable when the battery voltage is less
than V
V
Figure 2b. High-Efficiency Operating Configuration for
V
100 F
OUT
IN
BATT
V
IN
> V
.
= +1.8V TO +11V
< 6.5V
R6
R5
OUT
0.1 F
Configuration 2: High Efficiency, V
IN
OUT
Configuration 1: High Efficiency, 7V Max V
is only slightly higher than V
, but the AC adapter output is greater than
(Figure 2a). When V
FV
SHDN
STBY
N/E
LBO
LBI+
LBI-
REF
so that OUT maintains regulation. V
PGND
MAX710
IN
GND
> V
FV
ILIM
OUT
forward drop, while V
3/5
OUT
PS
LX
IN
(where linear regu-
IN
< V
OUT
> V
R5 = R6
L1
R5 = R6 (4.08)
WHEN V
AND V
OUT
OUT
, conversion
BATT
IN
4.7 F
(V
REF
= 6.5V
, the IC
, the lin-
IN
< V
= 1.28V
V
- V
REF
OUT
REF
100 F
OUT
)
PS
FV
IN
).