19-3293; Rev. 2; 9/96
CMOS Monolithic Voltage Converter
_______________General Description
The MAX660 monolithic, charge-pump voltage inverter
converts a +1.5V to +5.5V input to a corresponding
-1.5V to -5.5V output. Using only two low-cost
capacitors, the charge pump’s 100mA output replaces
switching regulators, eliminating inductors and their
associated cost, size, and EMI. Greater than 90%
efficiency over most of its load-current range combined
with a typical operating current of only 120µA provides
ideal performance for both battery-powered and board-
level voltage conversion applications. The MAX660 can
also double the output voltage of an input power supply
or battery, providing +9.35V at 100mA from a +5V
input.
A frequency control (FC) pin selects either 10kHz typ or
80kHz typ (40kHz min) operation to optimize capacitor
size and quiescent current. The oscillator frequency
can also be adjusted with an external capacitor or
driven with an external clock. The MAX660 is a pin-
compatible, high-current upgrade of the ICL7660.
The MAX660 is available in both 8-pin DIP and small-
outline packages in commercial, extended, and military
temperature ranges.
For 50mA applications, consider the MAX860/MAX861
pin-compatible devices (also available in ultra-small
µMAX packages).
___________________________ Features
♦
Small Capacitors
♦
0.65V Typ Loss at 100mA Load
♦
Low 120µA Operating Current
♦
6.5Ω Typ Output Impedance
♦
Guaranteed R
OUT
< 15Ω for C1 = C2 = 10µF
♦
Pin-Compatible High-Current ICL7660 Upgrade
♦
Inverts or Doubles Input Supply Voltage
♦
Selectable Oscillator Frequency: 10kHz/80kHz
♦
88% Typ Conversion Efficiency at 100mA
(I
L
to GND)
MAX660
______________Ordering Information
PART
MAX660CPA
MAX660CSA
MAX660C/D
MAX660EPA
MAX660ESA
MAX660MJA
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP
*Contact factory for dice specifications.
________________________Applications
Laptop Computers
Medical Instruments
Interface Power Supplies
Hand-Held Instruments
Operational-Amplifier Power Supplies
_________Typical Operating Circuits
+V
IN
1.5V TO 5.5V
1 FC
2
C1
1µF to 150µF
3
4
V+ 8
7
6
CAP+
MAX660
OSC
GND
CAP-
LV
__________________Pin Configuration
TOP VIEW
OUT 5
INVERTED
NEGATIVE
VOLTAGE
OUTPUT
C2
1µF to 150µF
VOLTAGE INVERTER
DOUBLED
POSITIVE
VOLTAGE
OUTPUT
C2
1µF to 150µF
1
FC
CAP+
1
2
8
7
V+
OSC
LV
OUT
C1
1µF to 150µF
+V
IN
2.5V TO 5.5V
2
3
4
FC
V+ 8
7
6
5
CAP+
MAX660
OSC
GND
CAP-
LV
OUT
GND
3
CAP-
4
MAX660
6
5
DIP/SO
POSITIVE VOLTAGE DOUBLER
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
CMOS Monolithic Voltage Converter
MAX660
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V+ to GND, or GND to OUT) .......................+6V
Operating Temperature Ranges
LV Input Voltage ...............................(OUT - 0.3V) to (V+ + 0.3V)
MAX660C_ _ ........................................................0°C to +70°C
FC and OSC Input Voltages........................The least negative of
MAX660E_ _ .....................................................-40°C to +85°C
(OUT - 0.3V) or (V+ - 6V) to (V+ + 0.3V)
MAX660MJA ...................................................-55°C to +125°C
OUT and V+ Continuous Output Current..........................120mA
Storage Temperature Range............................... -65°to +160°C
Output Short-Circuit Duration to GND (Note 1) ....................1sec
Lead Temperature (soldering, 10sec) ........................... +300°C
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 9.09mW/°C above + 70°C) ............727mW
SO (derate 5.88mW/°C above +70°C) ..........................471mW
CERDIP (derate 8.00mW/°C above +70°C) ..................640mW
Note 1:
OUT may be shorted to GND for 1sec without damage, but shorting OUT to V+ may damage the device and should be
avoided. Also, for temperatures above +85°C, OUT must not be shorted to GND or V+, even instantaneously, or device
damage may result.
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.
ELECTRICAL CHARACTERISTICS
(V+ = 5V, C1 = C2 = 150µF, test circuit of Figure 1, FC = open, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Note 2)
PARAMETER
Operating Supply Voltage
R
L
= 1kΩ
CONDITIONS
Inverter, LV = open
Inverter, LV = GND
Doubler, LV = OUT
Supply Current
Output Current
No load
FC = open, LV = open
FC = V+, LV = open
100
100
15
6.5
5
40
10
80
±1
±8
96
92
98
96
88
99.00
99.96
%
%
10.0
12
kHz
µA
Ω
MIN
3.0
1.5
2.5
0.12
1
TYP
MAX
5.5
5.5
5.5
0.5
3
mA
mA
V
UNITS
T
A
≤
+85°C, OUT more negative than -4V
T
A
> +85°C, OUT more negative than -3.8V
T
A
≤
+85°C, C1 = C2 = 10µF, FC = V+ (Note 4)
I
L
= 100mA
FC = open
FC = V+
FC = open
FC = V+
R
L
= 1kΩ connected between V+ and OUT
R
L
= 500Ω connected between OUT and GND
I
L
= 100mA to GND
T
A
≤
+85°C, C1 = C2 = 150µF
T
A
≤
+85°C
Output Resistance (Note 3)
Oscillator Frequency
OSC Input Current
Power Efficiency
Voltage-Conversion
Efficiency
No load
Note 2:
In the test circuit, capacitors C1 and C2 are 150µF, 0.2Ω maximum ESR, aluminum electrolytics.
Capacitors with higher ESR may reduce output voltage and efficiency. See
Capacitor Selection
section.
Note 3:
Specified output resistance is a combination of internal switch resistance and capacitor ESR. See
Capacitor Selection
section.
Note 4:
The ESR of C1 = C2
≤
0.5Ω. Guaranteed by correlation, not production tested.
2
_______________________________________________________________________________________
CMOS Monolithic Voltage Converter
__________________________________________Typical Operating Characteristics
All curves are generated using the test circuit of Figure 1
with V+ =5V, LV = GND, FC = open, and T
A
= +25°C,
unless otherwise noted. The charge-pump frequency is
one-half the oscillator frequency. Test results are also
valid for doubler mode with GND = +5V, LV = OUT, and
OUT = 0V, unless otherwise noted; however, the input
voltage is restricted to +2.5V to +5.5V.
MAX660
I
S
V+
1
2
3
4
FC
CAP+
V+ 8
OSC 7
V+
(+5V )
C1
GND
MAX660
LV 6
CAP-
OUT 5
I
L
V
OUT
C2
R
L
Figure 1. MAX660 Test Circuit
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX660-1
SUPPLY CURRENT
vs. OSCILLATOR FREQUENCY
MAX660-4
OUTPUT VOLTAGE AND EFFICIENCY
vs. LOAD CURRENT, V+ = 5V
-3.0
MAX660
-3.4
ICL7660
EFF.
V
OUT
ICL7660
-4.6
MAX660
68
92
EFFICIENCY (%)
100
MAX660-6A
400
350
SUPPLY CURRENT (µA)
300
250
200
150
100
50
0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
LV = OPEN
LV = GND
LV = OUT
10
SUPPLY CURRENT (mA)
1
OUTPUT VOLTAGE (V)
-3.8
84
-4.2
76
0.1
0.01
5.5
0.1
1
10
100
SUPPLY VOLTAGE (V)
OSCILLATOR FREQUENCY (kHz)
-5.0
0
20
40
60
80
LOAD CURRENT (mA)
60
100
EFFICIENCY vs. LOAD CURRENT
MAX660-2
OUTPUT VOLTAGE DROP
vs. LOAD CURRENT
OUTPUT VOLTAGE DROP FROM SUPPLY (V)
MAX660-3
OUTPUT VOLTAGE
vs. OSCILLATOR FREQUENCY
I
LOAD
= 1mA
-4.5
I
LOAD
= 10mA
MAX660-5
100
V+ = 5.5V
92
EFFICIENCY (%)
1.2
1.0
0.8
0.6
0.4
V+ = 4.5V
0.2
V+ = 5.5V
0
V+ = 1.5V
V+ = 2.5V
-5.0
84
V+ = 3.5V
76
V+ = 1.5V
V+ = 4.5V
OUTPUT VOLTAGE (V)
V+ = 3.5V
-4.0
I
LOAD
= 80mA
-3.5
68
V+ = 2.5V
60
0
20
40
60
80
100
LOAD CURRENT (mA)
-3.0
0
10 20
30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
0.1
1
10
100
OSCILLATOR FREQUENCY (kHz)
_________________________________________________________________________________________________
3
CMOS Monolithic Voltage Converter
MAX660
_____________________________Typical Operating Characteristics (continued)
EFFICIENCY
vs. OSCILLATOR FREQUENCY
MAX660-6
OSCILLATOR FREQUENCY
OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
vs. SUPPLY VOLTAGE
MAX660-7
96
92
88
EFFICIENCY (%)
84
80
76
72
68
64
60
0.1
1
10
I
LOAD
= 80mA
I
LOAD
= 10mA
I
LOAD
= 1mA
LV = GND
LV = GND
LV = GND
OSCILLATOR FREQUENCY (kHz)
10
8
6
4
2
0
1.5
2.5
3.5
4.5
LV = OPEN
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY (kHz)
80
80
LV =
= OPEN
LV
OPEN
60
60
FC = V+, OSC = OPEN
40
FC = V+, OSC = OPEN
40
FC = OPEN, OSC = OPEN
20
20
0
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
1.0 1.5 2.0
SUPPLY
3.0 3.5
(V)
4.5 5.0 5.
2.5
VOLTAGE
4.0
SUPPLY VOLTAGE (V)
100
5.5
OSCILLATOR FREQUENCY (kHz)
SUPPLY VOLTAGE (V)
OSCILLATOR FREQUENCY
vs. EXTERNAL CAPACITANCE
MAX660-9
OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX660-10
OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX660-10A
100
OSCILLATOR FREQUENCY (kHz)
100
OSCILLATOR FREQUENCY (kHz)
80
FC = V+, OSC = OPEN, RL = 100Ω
60
12
10
8
6
4
2
0
FC = OPEN, OSC = OPEN
R
L
= 100Ω
10
FC = V+
1
FC = OPEN
0.1
40
20
0.01
1
10
100
CAPACITANCE (pF)
1000
10000
0
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
OSCILLATOR FREQUENCY (kHz)
-60
-40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
OUTPUT SOURCE RESISTANCE
vs. SUPPLY VOLTAGE
MAX660-13
OUTPUT SOURCE RESISTANCE (Ω)
OUTPUT SOURCE RESISTANCE (Ω)
12
10
8
6
4
2
0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
MAX660-11
OUTPUT SOURCE RESISTANCE (Ω)
25
20
15
25
20
15
V+ = 1.5V
10
V+ = 3.0V
5
V+ = 5.0V
0
C1, C2 = 150µF OS-CON CAPACITORS
R
L
= 100Ω
C1, C2 = 150µF ALUMINUM
ELECTROLYTIC
CAPACITORS
R
L
= 100Ω
V+ = 1.5V
10
5
V+ = 3.0V
V+ = 5.0V
5.5
0
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
-60 -40 -20 0
20 40 60 80 100 120 140
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
MAX660-12
14
OUTPUT SOURCE RESISTANCE
vs. TEMPERATURE
30
30
OUTPUT SOURCE RESISTANCE
vs. TEMPERATURE
MAX660-8
100
OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
12
100
CMOS Monolithic Voltage Converter
OUTPUT CURRENT vs. CAPACITANCE:
V
IN
= +4.5V, V
OUT
= -4V
CURRENT (mA)
100
CURRENT (mA)
80
60
40
20
0
0.33 1.0 2.0 2.2 4.7 10 22 47 100 220
CAPACITANCE (µF)
FC = V+
OSC = OPEN
MAX660 CHART -01
200
150
100
50
0
FC = V+
OSC = OPEN
0.33 1.0 2.0 2.2 4.7 10 22 47 100 220
CAPACITANCE (µF)
MAX660 CHART -03
50
CURRENT (mA)
40
30
20
10
0
FC = V+
OSC = OPEN
100
CURRENT (mA)
80
60
40
20
0
FC = V+
OSC = OPEN
0.33 1.0 2.0 2.2 4.7 10 22 47 100 220
CAPACITANCE (µF)
0.33 1.0 2.0 2.2 4.7 10 22 47 100 220
CAPACITANCE (µF)
______________________________________________________________Pin Description
NAME
PIN
NAME
INVERTER
Frequency Control for internal oscillator, FC = open,
f
OSC
= 10kHz typ; FC = V+, f
OSC
= 80kHz typ (40kHz min),
FC has no effect when OSC pin is driven externally.
Charge-Pump Capacitor, Positive Terminal
Power-Supply Ground Input
Charge-Pump Capacitor, Negative Terminal
Output, Negative Voltage
Low-Voltage Operation Input. Tie LV to GND when input
voltage is less than 3V. Above 3V, LV may be connected to
GND or left open; when overdriving OSC, LV must be
connected to GND.
Oscillator Control Input. OSC is connected to an internal
15pF capacitor. An external capacitor can be added to slow
the oscillator. Take care to minimize stray capacitance. An
external oscillator may also be connected to overdrive OSC.
Power-Supply Positive Voltage Input
FUNCTION
DOUBLER
1
2
3
4
5
FC
CAP+
GND
CAP-
OUT
Same as Inverter
Same as Inverter
Power-Supply Positive Voltage Input
Same as Inverter
Power-Supply Ground Input
6
LV
LV must be tied to OUT for all input
voltages.
7
OSC
Same as Inverter; however, do not over-
drive OSC in voltage-doubling mode.
8
V+
Positive Voltage Output
5
_______________________________________________________________________________________
MAX660 CHART -04
60
OUTPUT CURRENT vs. CAPACITANCE:
V
IN
= +3.0V, V
OUT
= -2.7V
120
OUTPUT CURRENT vs. CAPACITANCE:
V
IN
= +3.0V, V
OUT
= -2.4V
MAX660 CHART -02
120
250
OUTPUT CURRENT vs. CAPACITANCE:
V
IN
= +4.5V, V
OUT
= -3.5V
MAX660
