Rainbow Electronics MAX1681 - Manual

_______________General Description
The MAX1680/MAX1681 inductorless switched-capaci-
tor voltage converters either invert an input voltage of
+2.0V to +5.5V or double it while supplying up to
125mA output current. They have a selectable-frequen-
cy option that allows the use of small capacitors: 4.7µF
(MAX1680), 1µF (MAX1681). With their high output cur-
rent capability, these charge-pump devices are suit-
able replacements for inductor-based regulators, which
require more expensive external components and addi-
tional board space.
The devices’ equivalent output resistance (typically
3.5
Ω
) allows them to deliver as much as 125mA with
only a 440mV drop. A shutdown feature reduces quies-
cent current to less than 1µA. The MAX1680/MAX1681
are available in 8-pin SO packages. For devices that
deliver up to 50mA in smaller µMAX packages, refer to
the MAX860/MAX861 data sheet.
________________________Applications
Local Negative Supplies
Interface Power Supplies
Op-Amp Power Supplies
MOSFET Bias
____________________________Features
♦ Selectable Switching Frequencies:
125kHz/250kHz (MAX1680)
500kHz/1MHz (MAX1681)
♦ Allow Use of Small Capacitors
(1µF for the MAX1681)
♦ 125mA Output Current
♦ 3.5
Ω
Output Impedance
♦ 1µA Logic-Controlled Shutdown
♦ Configurable as Voltage Inverters or Doublers
♦ +2.0V to +5.5V Input Voltage Range
♦ Available in 8-Pin SO Packages
♦ 90% Efficiency
MAX1680/MAX1681
125mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters
________________________________________________________________ Maxim Integrated Products 1
MAX1681
FSEL IN
CAP+ SHDN
GND
C1
1 µ F
+V INPUT
+3V TO +5.5V
INVERTED
OUTPUT
VOLTAGE
C2
1 µ F
1 µ F
LV
CAP-
INVERTER CONFIGURATION
OUT
MAX1681
FSEL IN
CAP+ SHDN
GND
C1
1 µ F
C2
1 µ F
DOUBLED
OUTPUT
VOLTAGE
+V
INPUT
+4V TO +5.5V
NOTE: USE 4.7 µ F CAPACITORS FOR MAX1680
INPUT VOLTAGE RANGE: +2.5V TO +5.5V.
NOTE: USE 4.7 µ F CAPACITORS FOR MAX1680
INPUT VOLTAGE RANGE: +2.0V TO +5.5V.
1 µ F
LV
CAP-
DOUBLER CONFIGURATION
OUT
__________________________________________________Typical Operating Circuits
19-1247; Rev 0; 7/97
PART
MAX1680 C/D
MAX1680ESA
MAX1681 C/D 0°C to +70°C
-40°C to +85°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
Dice*
8 SO
Dice*
______________Ordering Information
* Contact factory for dice specifications.
Pin Configuration appears at end of data sheet.
MAX1681ESA -40°C to +85°C 8 SO
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.