Rainbow Electronics MAX1797 - Manual

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
♦ >95% Efficiency
♦ True-Shutdown Circuitry
Output Disconnects from Input in Shutdown
No External Schottky Diode Needed
♦ 25µA Quiescent Supply Current
♦ Low-Noise Antiringing Feature
♦ LBI/LBO Comparator Enabled in Shutdown
♦ 2µA Shutdown Current
♦ 8-Pin µMAX Package
MAX1795/MAX1796/MAX1797
Low Supply Current, Step-Up DC-DC Converters
with True-Shutdown
________________________________________________________________ Maxim Integrated Products 1
1
2
3
4
8
7
6
5
BATT
OUT
LX
GND
LBO
FB
LBI
MAX1795
MAX1796
MAX1797
µMAX
TOP VIEW
SHDN
Pin Configuration
GND
LBI
LBO
BATT
FB
LX
OUT
MAX1795
MAX1796
MAX1797
SHDN
OUT
IN
0.7V TO
5.5V
ON
OFF
Typical Operating Circuit
19-1798; Rev 0; 12/00
Ordering Information
PART TEMP. RANGE PIN-PACKAGE
MAX1795 EUA -40 °C to +85°C 8 µMAX
MAX1796 EUA -40 °C to +85°C 8 µMAX
MAX1797 EUA -40 °C to +85°C 8 µMAX
True-Shutdown is a trademark of Maxim Integrated Products.
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.