Low-supply Current, Step-up Dc-dc Converters With True Shutdown

Maxim Integrated Products, Inc.

find MAX1796 datasheet
MAX1796 pinout,MAX1796 pin diagram
19-1798; Rev 0; 12/00
Low Supply Current, Step-up DC-DC Converters
with True-Shutdown
General Description
The MAX1795 MAX1796 MAX1797 are high efficiency
Step-up DC-DC Converters intended for small portable
hand-held devices. These devices feature Maxim’s
True-Shutdown™ circuitry, which fully disconnects the
output from the input in shutdown, improves efficiency,
and eliminates costly external components. All three
devices also feature Maxim’s proprietary LX-damping
circuitry for reduced EMI in noise-sensitive applica-
tions. For additional in-system flexibility, a Battery moni-
toring Comparator (LBI/LBO) remains active even when
the DC-DC Converter is in shutdown.
The input voltage range is +0.7V to V
OUT
, where V
OUT
can be set from +2V to +5.5V. Startup is guaranteed
from +0.85V. The MAX1795 MAX1796 MAX1797 have a
preset, pin-selectable 5V or 3.3V output. The output
can also be adjusted to other voltages, using two exter-
nal Resistors The three devices differ only in their cur-
rent limits, allowing optimization of external components
for different loads: The MAX1795 MAX1796 and
MAX1797 have current limits of 0.25A 0.5A, and 1A,
respectively. All devices are packaged in a compact 8-
pin µMAX package that is only 1.09mm tall and half the
size of an 8-pin SO.
o
>95% Efficiency
o
True-Shutdown Circuitry
Output Disconnects from Input in Shutdown
No External Schottky Diode Needed
o
25µA Quiescent Supply Current
o
Low-Noise Antiringing Feature
o
LBI/LBO Comparator Enabled in Shutdown
o
2µA Shutdown Current
o
8-Pin µMAX Package
Features
Ordering Information
PART
EUA
MAX1796
EUA
EUA
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8
µMAX
8
µMAX
8
µMAX
________________________Applications
Portable Digital Audio Players
PDAs/Palmtops
Wireless Handsets
Portable Terminals
True-Shutdown is a trademark of Maxim Integrated Products.
Pin Configuration
IN
0.7V TO
5.5V
LBI
FB
LBO
SHDN
1
2
3
4
8
BATT
OUT
LX
GND
OFF
ON
Typical Operating Circuit
TOP VIEW
BATT
MAX1796
LX
MAX1796
µMAX
7
6
5
LBI
LBO
SHDN
OUT
FB
OUT
GND
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.