Maxim MAX679C-D Datasheet
_______________General Description
The MAX679 step-up, regulated charge pump generates 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 DCDC 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.
________________________Applications
Battery-Powered Applications
Miniature Equipment
Backup-Battery Boost Converters
Translators
Two-Way Pagers
____________________________Features
♦ Regulated 3.3V ±4% Output
♦ Ultra-Small:
1.1mm-High, 8-Pin µMAX Package
♦ No Inductors Required
♦ Up to 1MHz Operation
(small external components)
♦ Fits into 0.05 in.
2
♦ Up to 85% Efficiency
♦ 1.8V to 3.6V Input Voltage Range
♦ 50µA Quiescent Supply Current
♦ 1µA Shutdown Current
MAX679
Regulated 3.3V Charge Pump
________________________________________________________________
Maxim Integrated Products
1
C1-
PGND
GND
1
2
87OUT
C1+
SHDN
IN
FSET
µMAX
TOP VIEW
3
4
6
5
MAX679
__________________Pin Configuration
MAX679
OUT
C1+
C1-
OFF/ON
IN
FSET
SHDN
INPUT
2V to 3.6V
OUTPUT
3.3V, 20mA
C
IN
C
OUT
C1
GND
PGND
__________Typical Operating Circuit
19-1217; Rev 0; 4/97
PART
MAX679C/D 0°C to +70°C
TEMP. RANGE PIN-PACKAGE
Dice*
______________Ordering Information
*
Dice are tested at TA= +25°C only.
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
MAX679EUA -40°C to +85°C 8 µMAX
MAX679
Regulated 3.3V Charge Pump
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= V
SHDN
= V
FSET
= 2V, CIN= 4.7µF, C1 = 0.33µF, C
OUT
= 10µF, TA= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1: Specifications to -40°C are guaranteed by design, not production tested.
IN, OUT, SHDN, FSET to GND....................................-0.3V to 6V
PGND to GND.....................................................................±0.3V
C1- to GND..................................................-0.3V to (V
IN
+ 0.3V)
C1+ to GND..............................................-0.3V to (V
OUT
+ 0.3V)
OUT Short to GND..............................................................10sec
Continuous Power Dissipation (T
A
= +70°C)
µMAX (derate 4.1mW/°C above +70°C) .......................330mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
FSET = GND
FSET,SHDN = GND or V
IN
VIN= 2V, I
OUT
= 10mA
VIN= 3.6V
VIN= 1.8V
VIN= 1.8V, V
OUT
> 3.17V
VIN= 2.5V, FSET = IN or GND
V
OUT
= 3.6V, SHDN = GND
OUT = GND, VIN= 3.3V
VIN= 3.3V
FSET = IN
CONDITIONS
%80Efficiency
mA100 200Output Short-Circuit Current
kHz
700 1000 1300
V0.8 1.6
V1.8 3.6Input Voltage
Input Undervoltage Lockout Voltage
260 330 450
Switching Frequency
µA0.1 1
FSET, SHDN Input Leakage Current
V
0.7 x 0.5 x
V
IN
V
IN
FSET, SHDN Input Voltage High
V
0.5 x 0.3 x
V
IN
V
IN
FSET, SHDN Input Voltage Low
mA20Output Current
µA50 80No-Load Supply Current
µA15 25Leakage Current into OUT in Shutdown
µA1 5Supply Current in Shutdown
UNITSMIN TYP MAXPARAMETER
2V < VIN< 3.3V,
0mA < I
OUT
< 20mA
3.15 3.45
Output Voltage
TA= 0°C to +85°C
TA= -40°C to +85°C
V
3.17 3.3 3.43
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