MAX679 Datasheet, PDF (1/6 Pages) Maxim Integrated Products – Regulated 3.3V Charge Pump

19-1217; Rev 0; 4/97
Regulated 3.3V Charge Pump
_______________General Description
The MAX679 step-up, regulated charge pump gener-
ates a 3.3V ±4% output voltage from a 1.8V to 3.6V
input voltage (two alkaline, NiCd, or NiMH; or one
Lithium-Ion battery). Output current is 20mA (min) from
a 2.0V input. Only three external capacitors are needed
to build a complete DC-DC converter.
The MAX679’s switching frequency is pin selectable at
330kHz or 1MHz to allow trade-offs between lowest
supply current and smallest-size capacitors. The logic
shutdown function reduces the supply current to 5µA
(max) and disconnects the load from the input. Special
soft-start circuitry prevents excessive current from
being drawn from the battery during start-up. This DC-
DC converter requires no inductors and has low EMI. It
is available in the ultra-small µMAX package, which is
only 1.11mm high and half the area of an 8-pin SO.
____________________________Features
o Regulated 3.3V ±4% Output
o Ultra-Small:
1.1mm-High, 8-Pin µMAX Package
o No Inductors Required
o Up to 1MHz Operation
(small external components)
o Fits into 0.05 in.²
o Up to 85% Efficiency
o 1.8V to 3.6V Input Voltage Range
o 50µA Quiescent Supply Current
o 1µA Shutdown Current
________________________Applications
Battery-Powered Applications
Miniature Equipment
Backup-Battery Boost Converters
Translators
Two-Way Pagers
______________Ordering Information
PART
MAX679C/D
MAX679EUA
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
*Dice are tested at T_A = +25°C only.
PIN-PACKAGE
Dice*
8 µMAX
__________Typical Operating Circuit ^{__________________Pin Configuration}
INPUT
2V to 3.6V
C_IN
IN
OUT
MAX679
OFF/ON
FSET
C1+
SHDN
C1-
PGND GND
OUTPUT
3.3V, 20mA
C_OUT
C1
TOP VIEW
FSET 1
SHDN 2
IN 3
GND 4
MAX679
8 OUT
7 C1+
6 C1-
5 PGND
µMAX
________________________________________________________________ Maxim Integrated Products 1
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