19-0239; Rev 1; 11/96
50mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters
_______________General Description
The MAX860/MAX861 charge-pump voltage converters
invert input voltages ranging from +1.5V to +5.5V, or
double input voltages ranging from +2.5V to +5.5V.
Because of their high switching frequencies, these
devices use only two small, low-cost capacitors. Their
50mA output makes switching regulators unnecessary,
eliminating inductors and their associated cost, size,
and EMI. Greater than 90% efficiency over most of the
load-current range, combined with a typical operating
current of only 200µA (MAX860), provides ideal perfor-
mance for both battery-powered and board-level volt-
age-conversion applications.
A frequency-control (FC) pin provides three switching-
frequencies to optimize capacitor size and quiescent
current and to prevent interference with sensitive cir-
cuitry. Each device has a unique set of three available
— —
— –
frequencies. A shutdown (SHDN) pin reduces current
consumption to less than 1µA. The MAX860/MAX861
are suitable for use in applications where the ICL7660
and MAX660's switching frequencies are too low. The
MAX860/MAX861 are available in 8-pin µMAX and
SO packages.
____________________________Features
o
8-Pin, 1.11mm High µMAX Package
o
Invert or Double the Input Supply Voltage
o
Three Selectable Switching Frequencies
o
High Frequency Reduces Capacitor Size
o
87% Efficiency at 50mA
o
200µA Quiescent Current (MAX860)
o
1µA Shutdown Supply Current
o
600mV Voltage Drop at 50mA Load
o
12Ω Output Resistance
MAX860/MAX861
______________Ordering Information
PART
MAX860ISA
MAX860IUA
MAX860C/D
MAX860ESA
MAX860MJA
MAX861ISA
MAX861IUA
MAX861C/D
MAX861ESA
MAX861MJA
TEMP. RANGE
-25°C to +85°C
-25°C to +85°C
0°C to +70°C
-40°C to +85°C
-55°C to +125°C
-25°C to +85°C
-25°C to +85°C
0°C to +70°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 SO
8 µMAX
Dice*
8 SO
8 CERDIP
†
8 SO
8 µMAX
Dice*
8 SO
8 CERDIP
†
________________________Applications
Portable Computers
Medical Instruments
Interface Power Supplies
Hand-Held Instruments
Operational-Amplifier Power Supplies
__________Typical Operating Circuit
1
2
3
C1 10µF 4
FC
MAX860
V
DD
8
7
6
5
INPUT
VOLTAGE
+1.5V TO +5.5V
* Dice are tested at T
A
= +25°C, DC parameters only.
†
Contact factory for availability.
MAX861
C1+
GND
C1-
SHDN
LV
OUT
__________________Pin Configuration
INVERTED
NEGATIVE
OUTPUT
10µF
C2
TOP VIEW
VOLTAGE INVERTER
FC 1
INPUT
VOLTAGE
+2.5V TO +5.5V
1
2
3
C1
10µF 4
8
FC
MAX860
V
DD
MAX861
C1+
GND
C1-
SHDN
LV
OUT
7
6
5
DOUBLED
POSITIVE
OUTPUT
10µF
C2
8
7
V
DD
SHDN
LV
OUT
C1+ 2
GND 3
C1- 4
MAX860
MAX861
6
5
SO/µMAX
POSITIVE VOLTAGE DOUBLER
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
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