MAX863 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – Dual, High-Efficiency, PFM, Step-Up DC-DC Controller

19-1218; Rev 1; 6/97
EVALUAATVIOANILKAIBTLMEANUAL
Dual, High-Efficiency, PFM, Step-Up
DC-DC Controller
_______________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)
__________________Pin Configuration
TOP VIEW
SENSE1 1
V_DD 2
FB1 3
BOOT 4
CS1 5
EXT1 6
GND 7
PGND 8
MAX863
QSOP
16 REF
15 SHDN2
14 LBI
13 LBO
12 FB2
11 SHDN1
10 CS2
9 EXT2
____________________________Features
o Smallest Dual Step-Up Converter: 16-Pin QSOP
o 90% Efficiency
o 1.5V Start-Up Voltage
o 85µA Max Total Quiescent Supply Current
o 1µA Shutdown Mode
o Independent Shutdown Inputs
o Drives Surface-Mount, Dual N-Channel MOSFETs
o Low-Battery Input/Output Comparator
o Step-Up/Down Configurable
______________Ordering Information
PART
MAX863C/D
MAX863EEE
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
*Dice are tested at T_A = +25°C.
PIN-PACKAGE
Dice*
16 QSOP
__________Typical Operating Circuit
V_IN
OUT1
SENSE1 V_DD BOOT
N
EXT1
EXT2
CS1
CS2
OUT2
N
MAX863
LBO
LOW-BATTERY
DETECTOR OUTPUT
LBI
FB2
SHDN1
SHDN2
REF
FB1 PGND GND
ON/OFF
________________________________________________________________ Maxim Integrated Products 1
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