Rainbow Electronics MAX863 - Manual

_______________General Description
The MAX863 dual-output DC-DC converter contains
two independent step-up controllers in a single com-
pact package. This monolithic Bi-CMOS design draws
only 85µA when both controllers are on. The input
range extends down to 1.5V, permitting use in organiz-
ers, translators, and other low-power hand-held prod-
ucts. The MAX863 provides 90% efficiency at output
loads from 20mA to over 1A. This space-saving device
is supplied in a 16-pin QSOP package that fits in the
same area as an 8-pin SOIC.
The device uses a current-limited, pulse-frequency-
modulated (PFM) control architecture that reduces start-
up surge currents and maintains low quiescent currents
for excellent low-current efficiency. Each controller
drives a low-cost, external, N-channel MOSFET switch,
whose size can be optimized for any output current or
voltage.
In larger systems, two MAX863s can be used to gener-
ate 5V, 3.3V, 12V, and 28V from just two or three bat-
tery cells. An evaluation kit (MAX863EVKIT) is available
to speed designs. For a single-output controller, refer to
the MAX608 and MAX1771 data sheets.
________________________Applications
2- and 3-Cell Portable Equipment
Organizers
Translators
Hand-Held Instruments
Palmtop Computers
Personal Digital Assistants (PDAs)
Dual Supply (Logic and LCD)
____________________________Features
♦ Smallest Dual Step-Up Converter: 16-Pin QSOP
♦ 90% Efficiency
♦ 1.5V Start-Up Voltage
♦ 85µA Max Total Quiescent Supply Current
♦ 1µA Shutdown Mode
♦ Independent Shutdown Inputs
♦ Drives Surface-Mount, Dual N-Channel MOSFETs
♦ Low-Battery Input/Output Comparator
♦ Step-Up/Down Configurable
MAX863
Dual, High-Efficiency, PFM, Step-Up
DC-DC Controller
________________________________________________________________ Maxim Integrated Products 1
MAX863
EXT2
CS2
OUT2 OUT1
V IN
N N
ON/OFF
FB2
SHDN1
EXT1
CS1
LBO
LOW-BATTERY
DETECTOR OUTPUT
LBI
SENSE1 V
DD
PGND
BOOT
GND FB1
SHDN2
REF
__________________Pin Configuration
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
SENSE1 REF
SHDN2
LBI
LBO
FB2
SHDN1
CS2
EXT2
TOP VIEW
MAX863
QSOP
V DD
FB1
EXT1
BOOT
CS1
GND
PGND
__________Typical Operating Circuit
19-1218; Rev 2; 2/98
PART
MAX863C/D
MAX863EEE -40°C to +85°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
Dice*
16 QSOP
EVALUATION KIT MANUAL
AVAILABLE
______________Ordering Information
*Dice are tested at T A = +25°C.
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.