MAX1795 Datasheet, PDF (1/13 Pages) Maxim Integrated Products – Low Supply Current, Step-Up DC-DC Converters with True-Shutdown

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.
________________________Applications
Portable Digital Audio Players
PDAs/Palmtops
Wireless Handsets
Portable Terminals
Features
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
PART
MAX1795 EUA
MAX1796 EUA
MAX1797 EUA
Ordering Information
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
True-Shutdown is a trademark of Maxim Integrated Products.
Pin Configuration
TOP VIEW
LBI 1
FB 2
LBO 3
SHDN 4
MAX1795
MAX1796
MAX1797
µMAX
8 BATT
7 OUT
6 LX
5 GND
Typical Operating Circuit
IN
0.7V TO
5.5V
BATT
LX
LBI
MAX1795
MAX1796
OUT
OUT
MAX1797 _FB
LBO
OFF
SHDN
ON
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.