MAX679EUA Fast Delivery |IC PHOENIX CO.,LIMITED

MAX679EUA ,Regulated 3.3V Charge PumpApplicationsPART TEMP. RANGE PIN-PACKAGEMAX679C/D 0°C to +70°C Dice*Miniature EquipmentMAX679EUA -4 ..
MAX679EUA ,Regulated 3.3V Charge PumpMAX67919-1217; Rev 0; 4/97Regulated 3.3V Charge Pump_______________
MAX679EUA ,Regulated 3.3V Charge PumpFeaturesThe MAX679 step-up, regulated charge pump gener-' Regulated 3.3V ±4% Outputates a 3.3V ±4% ..
MAX679EUA+ ,Regulated 3.3V Charge PumpApplicationsPART TEMP. RANGE PIN-PACKAGEMAX679C/D 0°C to +70°C Dice*Miniature EquipmentMAX679EUA -4 ..
MAX679EUA+T ,Regulated 3.3V Charge PumpFeaturesThe MAX679 step-up, regulated charge pump gener-♦ Regulated 3.3V ±4% Outputates a 3.3V ±4% ..
MAX680 ,+5V to ±10V Voltage Convertersapplications include: ±6V from 3V Lithium Cell Battery-OperatedEquipment_________Typical Operating ..
MB3778PFV ,Switching Regulator ControllerFUJITSU SEMICONDUCTORDS04-27203-6EDATA SHEETASSPSwitching Regulator ControllerMB3778nnnn DESCRIPTIO ..
MB3782 ,Switching Regulator ControllerFUJITSU SEMICONDUCTORDS04-27205-4EDATA SHEETASSP Power Supplies BIPOLARSwitching Regulator Controll ..
MB3782PF ,Switching Regulator ControllerFUJITSU SEMICONDUCTORDS04-27205-4EDATA SHEETASSP Power Supplies BIPOLARSwitching Regulator Controll ..
MB3785A ,Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)FUJITSU SEMICONDUCTORDS04-27208-1EDATA SHEETASSP BIPOLARSwitching Regulator Controller(4 Channels p ..
MB3785APFV ,Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)FUJITSU SEMICONDUCTORDS04-27208-1EDATA SHEETASSP BIPOLARSwitching Regulator Controller(4 Channels p ..
MB3789 ,Switching Regulator Controller (Supporting External Synchronization)FUJITSU SEMICONDUCTORDS04-27211-3EDATA SHEETASSP For Power Supply

MAX679EUA
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.
________________________Applications
Battery-Powered Applications
Miniature Equipment
Backup-Battery Boost Converters
Translators
Two-Way Pagers
____________________________FeaturesRegulated 3.3V ±4% OutputUltra-Small:
1.1mm-High, 8-Pin µMAX PackageNo Inductors RequiredUp to 1MHz Operation
(small external components)Fits into 0.05 in.2Up to 85% Efficiency1.8V to 3.6V Input Voltage Range50µA Quiescent Supply Current1µA Shutdown Current
MAX679
Regulated 3.3V Charge Pump
__________________Pin Configuration
__________Typical Operating Circuit
19-1217; Rev 0; 4/97
MAX679
Regulated 3.3V Charge Pump
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= VSHDN= VFSET= 2V, CIN= 4.7µF, C1 = 0.33µF, COUT= 10µF, TA= -40°C to +85°C,unless otherwise noted. Typical values
are at TA= +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 (VIN+ 0.3V)
C1+ to GND..............................................-0.3V to (VOUT+ 0.3V)
OUT Short to GND..............................................................10sec
Continuous Power Dissipation (TA= +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
Regulated 3.3V Charge Pump
__________________________________________Typical Operating Characteristics
(Typical Operating Circuit with: VIN= VSHDN= 2V, CIN= 4.7µF, C1 = 0.33µF, COUT= 10µF, tested in-circuit, TA= +25°C, unless
otherwise noted.)
MAX679
Regulated 3.3V Charge Pump
____________________________Typical Operating Characteristics (continued)
(Typical Operating Circuit with: VIN= VSHDN= 2V, CIN= 4.7µF, C1 = 0.33µF, COUT= 10µF, tested in-circuit, TA= +25°C, unless
otherwise noted.)
______________________________________________________________Pin Description
LOAD-TRANSIENT RESPONSE
(1mA TO 10mA LOAD, VIN = 3V)
MAX679 TOC11
VOUT
10mV/div
AC COUPLED
IOUT
5mA/div
100μs/div
LOAD-TRANSIENT RESPONSE
(1mA TO 10mA LOAD, VIN = 2V)
MAX679 TOC12
VOUT
10mV/div
AC COUPLED
IOUT
5mA/div
50μs/div
_______________Detailed Description
The MAX679 regulated charge pump has a 50% duty-
cycle clock. In phase one (charge phase), the charge-
transfer capacitor (C1) charges to the input voltage,
and output current is delivered by the output filter
capacitor (COUT). In phase two (transfer phase), C1 is
placed in series with the input and connects to the out-
put, transferring its charge to COUT. If the clock were to
run continuously, this process would eventually gener-
ate an output voltage equal to two times the input volt-
age (hence the name “doubler”).
The charge pump regulates by gating the oscillator on
and off as needed to maintain output regulation. This
method has low quiescent current, but to achieve
acceptable output ripple, C1 must be significantly
lower in value than COUT.
Start-Up Sequence
The MAX679 soft-start circuitry prevents excessive cur-
rent from being drawn from the battery at start-up or
when the output is shorted. This is done by limiting the
charge pump to 1/10 the normal current until either the
output is in regulation or the first 4096 charge-pump
MAX679
Regulated 3.3V Charge Pump
Figure 1. Block Diagram
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
MAX679
Regulated 3.3V Charge Pump
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
cycles (about 4ms) have elapsed. The start-up
sequence begins at power-up, when exiting shutdown,
or when recovering from a short circuit. If VINis less
than the 1.6V UVLO threshold, the device remains shut
down and ignores a high SHDNinput.
__________________Design Procedure
Optimize the charge-pump circuit for size, quiescent
current, and output ripple by properly selecting the
operating frequency and capacitors CIN, C1, and
COUT.
For lowest output ripple, select 1MHz operation (FSET
= IN). In addition, increasing COUTrelative to C1 will
further reduce ripple. For highest efficiency, select
330kHz operation (FSET = GND) and select the largest
practical values for COUTand C1 while maintaining a
30-to-1 ratio. See Table 1 for some suggested values
and the resulting output ripple.
Note that the capacitors must have low ESR (<20mΩ)
to maintain low ripple. Currently, only ceramic capaci-
tors can provide such low ESR; therefore, the output fil-
ter capacitors should be a combination of a 1µF
ceramic capacitor and a 10µF tantalum capacitor.
Smallest Size
Set the frequency to 1MHz by connecting FSET to IN.
Table 1 shows typical external component values.
Table 1. External Component Selection
PC Board Layout
Place C1, COUT, and CINclose to the IC. Connect
PGND and GND with a short trace.
Efficiency
Charge-pump efficiency is best at low frequency
(330kHz). The theoretical maximum efficiency is given
in the following equation:
Theoretical maximum efficiency = VOUT/ (2 x VIN)
Gate-charge losses amount to approximately 1mA from
the output at full switching frequency (about 5% to 7%
loss).
Table 2. Manufacturers of Low-ESR Capacitors
TRANSISTOR COUNT: 819
SUBSTRATE CONNECTED TO GND
___________________Chip Information

Partno	Mfg	Dc	Qty	Available	Descript
MAX679EUA	MAXIM	N/a	94	avai	Regulated 3.3V Charge Pump
MAX679EUA	MAXIM ?	N/a	50	avai	Regulated 3.3V Charge Pump
MAX679EUA	MAX	N/a	80	avai	Regulated 3.3V Charge Pump