19-3293; Rev. 2; 9/96
CMOS Monolithic Voltage Converter
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 boardlevel 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 pincompatible, high-current upgrade of the ICL7660.
The MAX660 is available in both 8-pin DIP and smalloutline 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).
________________________Applications
___________________________ Features
♦ Small Capacitors
♦ 0.65V Typ Loss at 100mA Load
♦ Low 120µA Operating Current
♦
♦
♦
♦
6.5Ω Typ Output Impedance
Guaranteed ROUT < 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
(IL to GND)
______________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX660CPA
0°C to +70°C
8 Plastic DIP
MAX660CSA
MAX660C/D
MAX660EPA
MAX660ESA
MAX660MJA
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
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP
*Contact factory for dice specifications.
_________Typical Operating Circuits
+VIN
1.5V TO 5.5V
Laptop Computers
Medical Instruments
1 FC
Interface Power Supplies
Hand-Held Instruments
2
Operational-Amplifier Power Supplies
C1
1µF to 150µF
3
4
__________________Pin Configuration
V+ 8
CAP+ MAX660 OSC
GND
CAP-
LV
7
6
OUT 5
INVERTED
NEGATIVE
VOLTAGE
OUTPUT
C2
1µF to 150µF
VOLTAGE INVERTER
TOP VIEW
1
FC
1
8
V+
CAP+
2
7
OSC
6
LV
5
OUT
GND 3
MAX660
CAP- 4
C1
1µF to 150µF
+VIN
2.5V TO 5.5V
2
3
4
FC
V+ 8
CAP+ MAX660 OSC
GND
LV
CAP-
OUT
7
DOUBLED
POSITIVE
VOLTAGE
OUTPUT
C2
1µF to 150µF
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
MAX660
_______________General Description
MAX660
CMOS Monolithic Voltage Converter
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 (TA = +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, TA = TMIN to TMAX, unless otherwise noted.) (Note 2)
PARAMETER
Operating Supply Voltage
Supply Current
Output Current
CONDITIONS
RL = 1kΩ
No load
MIN
TYP
Inverter, LV = open
3.0
5.5
Inverter, LV = GND
1.5
5.5
Doubler, LV = OUT
2.5
5.5
FC = open, LV = open
FC = V+, LV = open
TA ≤ +85°C, OUT more negative than -4V
100
TA > +85°C, OUT more negative than -3.8V
100
0.12
0.5
1
3
IL = 100mA
OSC Input Current
Power Efficiency
6.5
FC = open
5
10
FC = V+
40
80
FC = open
±1
FC = V+
±8
RL = 1kΩ connected between V+ and OUT
96
98
RL = 500Ω connected between OUT and GND
92
96
No load
mA
10.0
Ω
12
kHz
µA
%
88
IL = 100mA to GND
Voltage-Conversion
Efficiency
V
15
TA ≤ +85°C, C1 = C2 = 150µF
TA ≤ +85°C
Oscillator Frequency
UNITS
mA
TA ≤ +85°C, C1 = C2 = 10µF, FC = V+ (Note 4)
Output Resistance (Note 3)
MAX
99.00
99.96
%
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
All curves are generated using the test circuit of Figure 1
with V+ =5V, LV = GND, FC = open, and TA = +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
__________________________________________Typical Operating Characteristics
IS
V+
C1
V+ 8
1
FC
2
CAP+
3
GND MAX660 LV 6
4
V+
(+5V )
OSC 7
OUT 5
CAP-
RL
IL
VOUT
C2
Figure 1. MAX660 Test Circuit
SUPPLY CURRENT
vs. OSCILLATOR FREQUENCY
250
200
LV = GND
150
100
OUTPUT VOLTAGE (V)
SUPPLY CURRENT (mA)
LV = OUT
1
0.1
0
0.01
2.0
2.5
3.0
3.5
4.0
4.5
5.0
84
VOUT
-4.2
76
ICL7660
5.5
MAX660
-5.0
0.1
10
1
100
0
20
40
60
80
OSCILLATOR FREQUENCY (kHz)
LOAD CURRENT (mA)
EFFICIENCY vs. LOAD CURRENT
OUTPUT VOLTAGE DROP
vs. LOAD CURRENT
OUTPUT VOLTAGE
vs. OSCILLATOR FREQUENCY
84
V+ = 3.5V
V+ = 1.5V
76
V+ = 4.5V
V+ = 2.5V
68
20
40
60
LOAD CURRENT (mA)
80
100
68
60
100
MAX660-5
MAX660-3
1.0
ILOAD = 1mA
V+ = 1.5V
V+ = 2.5V
0.8
0.6
V+ = 3.5V
0.4
V+ = 4.5V
-4.5
ILOAD = 10mA
-4.0
ILOAD = 80mA
-3.5
0.2
V+ = 5.5V
-3.0
0
60
-5.0
OUTPUT VOLTAGE (V)
92
1.2
OUTPUT VOLTAGE DROP FROM SUPPLY (V)
V+ = 5.5V
MAX660-2
SUPPLY VOLTAGE (V)
100
0
EFF.
-4.6
LV = OPEN
1.5
92
ICL7660
-3.8
0
10 20
30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
0.1
1
MAX660-6A
100
MAX660
-3.4
300
50
EFFICIENCY (%)
-3.0
MAX660-4
350
SUPPLY CURRENT (µA)
10
MAX660-1
400
OUTPUT VOLTAGE AND EFFICIENCY
vs. LOAD CURRENT, V+ = 5V
10
100
OSCILLATOR FREQUENCY (kHz)
_________________________________________________________________________________________________
3
EFFICIENCY (%)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
_____________________________Typical Operating Characteristics (continued)
OSCILLATORFREQUENCY
FREQUENCY
OSCILLATOR
vs.SUPPLY
SUPPLYVOLTAGE
VOLTAGE
vs.
80
ILOAD = 10mA
76
72
ILOAD = 80mA
68
MAX660-7
LVLV= =OPEN
OPEN
60
60
FC = V+, OSC = OPEN
FC = V+, OSC = OPEN
40
40
LV = GND
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
2.5 3.0
3.5 (V)
4.0 4.5 5.0 5.
VOLTAGE
SUPPLY VOLTAGE (V)
100
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY
vs. EXTERNAL CAPACITANCE
MAX660-9
100
OSCILLATOR FREQUENCY (kHz)
1
FC = OPEN
0.1
0.01
80
FC = V+, OSC = OPEN, RL = 100Ω
60
40
20
10000
1000
OUTPUT SOURCE RESISTANCE
vs. SUPPLY VOLTAGE
MAX660-13
14
10
8
6
4
2
25
20
10
5.5
8
6
4
2
FC = OPEN, OSC = OPEN
RL = 100Ω
-60 -40 -20 0
20 40 60 80 100 120 140
20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT SOURCE RESISTANCE
vs. TEMPERATURE
OUTPUT SOURCE RESISTANCE
vs. TEMPERATURE
30
OUTPUT SOURCE RESISTANCE (Ω)
12
4.5
0
-60 -40 -20 0
CAPACITANCE (pF)
3.5
12
C1, C2 = 150µF ALUMINUM
ELECTROLYTIC
CAPACITORS
RL = 100Ω
15
V+ = 1.5V
10
V+ = 3.0V
5
30
OUTPUT SOURCE RESISTANCE (Ω)
100
10
2.5
SUPPLY VOLTAGE (V)
0
1
25
20
C1, C2 = 150µF OS-CON CAPACITORS
RL = 100Ω
15
V+ = 1.5V
10
V+ = 3.0V
5
V+ = 5.0V
V+ = 5.0V
0
1.5
2.0
2.5
3.0
3.5
4.0
SUPPLY VOLTAGE (V)
4
1.5
OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX660-11
OSCILLATOR FREQUENCY (kHz)
FC = V+
FC = OPEN, OSC = OPEN
4
OSCILLATOR FREQUENCY
vs. TEMPERATURE
100
10
6
0
OSCILLATOR FREQUENCY (kHz)
10
1
MAX660-10
0.1
LV = OPEN
8
2
64
60
10
MAX660-10A
88
84
80
80
MAX660-12
ILOAD = 1mA
12
OSCILLATOR FREQUENCY (kHz)
92
LV
LV==GND
GND
OSCILLATOR
OSCILLATORFREQUENCY
FREQUENCY(kHz)
(kHz)
96
EFFICIENCY (%)
100
MAX660-6
100
OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
MAX660-8
EFFICIENCY
vs. OSCILLATOR FREQUENCY
OUTPUT SOURCE RESISTANCE (Ω)
MAX660
CMOS Monolithic Voltage Converter
4.5
5.0
5.5
0
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
TEMPERATURE (°C)
_______________________________________________________________________________________
CMOS Monolithic Voltage Converter
80
60
40
250
100
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
OUTPUT CURRENT vs. CAPACITANCE:
VIN = +3.0V, VOUT = -2.7V
OUTPUT CURRENT vs. CAPACITANCE:
VIN = +3.0V, VOUT = -2.4V
40
30
20
10
120
100
CURRENT (mA)
FC = V+
OSC = OPEN
MAX660 CHART -04
CAPACITANCE (µF)
MAX660 CHART -03
CURRENT (mA)
150
0
0
50
FC = V+
OSC = OPEN
50
20
60
200
MAX660 CHART -02
FC = V+
OSC = OPEN
CURRENT (mA)
CURRENT (mA)
100
MAX660 CHART -01
120
OUTPUT CURRENT vs. CAPACITANCE:
VIN = +4.5V, VOUT = -3.5V
MAX660
OUTPUT CURRENT vs. CAPACITANCE:
VIN = +4.5V, VOUT = -4V
FC = V+
OSC = OPEN
80
60
40
20
0
0
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
FUNCTION
PIN
NAME
INVERTER
1
FC
Frequency Control for internal oscillator, FC = open,
fOSC = 10kHz typ; FC = V+, fOSC = 80kHz typ (40kHz min),
FC has no effect when OSC pin is driven externally.
Same as Inverter
2
CAP+
Charge-Pump Capacitor, Positive Terminal
Same as Inverter
3
GND
Power-Supply Ground Input
Power-Supply Positive Voltage Input
4
CAP-
Charge-Pump Capacitor, Negative Terminal
Same as Inverter
5
OUT
Output, Negative Voltage
Power-Supply Ground Input
LV must be tied to OUT for all input
voltages.
DOUBLER
6
LV
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.
7
OSC
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.
Same as Inverter; however, do not overdrive OSC in voltage-doubling mode.
8
V+
Power-Supply Positive Voltage Input
Positive Voltage Output
_______________________________________________________________________________________
5
MAX660
CMOS Monolithic Voltage Converter
______________Detailed Description
one-half of the charge-pump cycle. This introduces a
peak-to-peak ripple of:
IOUT
+ IOUT (ESRC2)
VRIPPLE =
2(fPUMP) (C2)
The MAX660 capacitive charge-pump circuit either
inverts or doubles the input voltage (see Typical
Operating Circuits). For highest performance, low
effective series resistance (ESR) capacitors should be
used. See Capacitor Selection section for more details.
When using the inverting mode with a supply voltage
less than 3V, LV must be connected to GND. This
bypasses the internal regulator circuitry and provides
best performance in low-voltage applications. When
using the inverter mode with a supply voltage above
3V, LV may be connected to GND or left open. The part
is typically operated with LV grounded, but since LV
may be left open, the substitution of the MAX660 for the
ICL7660 is simplified. LV must be grounded when overdriving OSC (see Changing Oscillator Frequency section). Connect LV to OUT (for any supply voltage) when
using the doubling mode.
For a nominal f PUMP of 5kHz (one-half the nominal
10kHz oscillator frequency) and C2 = 150µF with an
ESR of 0.2Ω, ripple is approximately 90mV with a
100mA load current. If C2 is raised to 390µF, the ripple
drops to 45mV.
Positive Voltage Doubler
The MAX660 operates in the voltage-doubling mode as
shown in the Typical Operating Circuit. The no-load
output is 2 x VIN.
Other Switched-Capacitor Converters
Please refer to Table 1, which shows Maxim’s chargepump offerings.
__________Applications Information
Changing Oscillator Frequency
Negative Voltage Converter
Four modes control the MAX660’s clock frequency, as
listed below:
The most common application of the MAX660 is as a
charge-pump voltage inverter. The operating circuit
uses only two external capacitors, C1 and C2 (see
Typical Operating Circuits).
Even though its output is not actively regulated, the
MAX660 is very insensitive to load current changes. A
typical output source resistance of 6.5Ω means that
with an input of +5V the output voltage is -5V under
light load, and decreases only to -4.35V with a load of
100mA. Output source resistance vs. temperature and
supply voltage are shown in the Typical Operating
Characteristics graphs.
Output ripple voltage is calculated by noting the output
current supplied is solely from capacitor C2 during
FC
OSC
Oscillator Frequency
Open
FC = V+
Open
Open
10kHz
80kHz
Open or
FC = V+
External
Capacitor
See Typical Operating
Characteristics
Open
External
Clock
External Clock Frequency
When FC and OSC are unconnected (open), the oscillator runs at 10kHz typically. When FC is connected to
V+, the charge and discharge current at OSC changes
from 1.0µA to 8.0µA, thus increasing the oscillator
Table 1. Single-Output Charge Pumps
Package
Op. Current
(typ, mA)
Output Ω
(typ)
Pump Rate
(kHz)
Input (V)
6
MAX828
MAX829
MAX860
MAX861
MAX660
MAX1044
ICL7662
ICL7660
SOT 23-5
SOT 23-5
SO-8,
µMAX
SO-8,
µMAX
SO-8
SO-8,
µMAX
SO-8
SO-8,
µMAX
0.06
0.15
0.03
0.25
0.08
20
20
12
12
6.5
6.5
125
55
12
35
6, 50, 130
13, 100, 150
5, 40
5
10
10
1.25 to 5.5
1.25 to 5.5
1.5 to 5.5
1.5 to 5.5
1.5 to 5.5
1.5 to 10
1.5 to 10
1.5 to 10
0.2 at 6kHz, 0.3 at 13kHz, 0.12 at 5kHz,
0.6 at 50kHz, 1.1 at 100kHz, 1 at 40kHz
1.4 at 130kHz 2.5 at 250kHz
_______________________________________________________________________________________
________________Capacitor Selection
Three factors (in addition to load current) affect the
MAX660 output voltage drop from its ideal value:
1) MAX660 output resistance
2) Pump (C1) and reservoir (C2) capacitor ESRs
3) C1 and C2 capacitance
The voltage drop caused by MAX660 output resistance
is the load current times the output resistance.
Similarly, the loss in C2 is the load current times C2’s
ESR. The loss in C1, however, is larger because it
handles currents that are greater than the load current
during charge-pump operation. The voltage drop due
to C1 is therefore about four times C1’s ESR multiplied
by the load current. Consequently, a low (or high) ESR
capacitor has a much greater impact on performance
for C1 than for C2.
Generally, as the pump frequency of the MAX660
increases, the capacitance values required to maintain
comparable ripple and output resistance diminish proportionately. The curves of Figure 2 show the total circuit
1kHz
2kHz
5kHz
10kHz
20kHz
50kHz
MAX660-fig 2
TOTAL OUTPUT SOURCE RESISTANCE (Ω)
In the inverter mode, OSC may also be overdriven by an
external clock source that swings within 100mV of V+
and GND. Any standard CMOS logic output is suitable
for driving OSC. When OSC is overdriven, FC has no
effect. Also, LV must be grounded when overdriving
OSC. Do not overdrive OSC in voltage-doubling mode.
Note: In all modes, the frequency of the signal appearing at CAP+ and CAP- is one-half that of the oscillator.
Also, an undesirable effect of lowering the oscillator frequency is that the effective output resistance of the
charge pump increases. This can be compensated by
increasing the value of the charge-pump capacitors
(see Capacitor Selection section and Typical Operating
Characteristics).
In some applications, the 5kHz output ripple frequency
may be low enough to interfere with other circuitry. If
desired, the oscillator frequency can then be increased
through use of the FC pin or an external oscillator as
described above. The output ripple frequency is onehalf the selected oscillator frequency. Increasing the
clock frequency increases the MAX660’s quiescent
current, but also allows smaller capacitance values to
be used for C1 and C2.
20
18
16
14
12
ESR = 0.25Ω
FOR BOTH
C1 AND C2
MAX660 OUTPUT
SOURCE RESISTANCE
ASSUMED TO BE
5.25Ω
10
8
6
4
2
0
1
2
4 6 8 10
100
1000
CAPACITANCE (µF)
Figure 2. Total Output Source Resistance vs. C1 and C2
Capacitance (C1 = C2)
output resistance for various capacitor values (the pump
and reservoir capacitors’ values are equal) and oscillator
frequencies. These curves assume 0.25Ω capacitor ESR
and a 5.25Ω MAX660 output resistance, which is why
the flat portion of the curve shows a 6.5Ω (RO MAX660 +
4 (ESRC1) + ESRC2) effective output resistance. Note:
R O = 5.25Ω is used, rather than the typical 6.5Ω,
because the typical specification includes the effect of
the ESRs of the capacitors in the test circuit.
In addition to the curves in Figure 2, four bar graphs in
the Typical Operating Characteristics show output current for capacitances ranging from 0.33µF to 220µF.
Output current is plotted for inputs of 4.5V (5V-10%) and
3.0V (3.3V-10%), and allow for 10% and 20% output
droop with each input voltage. As can be seen from the
graphs, the MAX660 6.5Ω series resistance limits
increases in output current vs. capacitance for values
much above 47µF. Larger values may still be useful,
however, to reduce ripple.
To reduce the output ripple caused by the charge
pump, increase the reservoir capacitor C2 and/or
reduce its ESR. Also, the reservoir capacitor must have
low ESR if filtering high-frequency noise at the output is
important.
Not all manufacturers guarantee capacitor ESR in the
range required by the MAX660. In general, capacitor ESR
is inversely proportional to physical size, so larger capacitance values and higher voltage ratings tend to reduce
ESR.
_______________________________________________________________________________________
7
MAX660
frequency eight times. In the third mode, the oscillator
frequency is lowered by connecting a capacitor
between OSC and GND. FC can still multiply the frequency by eight times in this mode, but for a lower
range of frequencies (see Typical Operating
Characteristics).
100kHz
CMOS Monolithic Voltage Converter
MAX660
CMOS Monolithic Voltage Converter
The following is a list of manufacturers who provide
low-ESR electrolytic capacitors:
Manufacturer/
Series
Phone
Fax
AVX TPS Series
(803) 946-0690
(803) 626-3123
Low-ESR
tantalum SMT
AVX TAG Series
(803) 946-0690
(803) 626-3123
Low-cost
tantalum SMT
Matsuo 267 Series (714) 969-2491
(714) 960-6492
Low-cost
tantalum SMT
Sprague 595
Series
(603) 224-1961
(603) 224-1430
Aluminum electrolytic thru-hole
Sanyo MV-GX
Series
(619) 661-6835
(619) 661-1055
Aluminum electrolytic SMT
Sanyo CV-GX
Series
(619) 661-6835
(619) 661-1055
Aluminum electrolytic thru-hole
Nichicon PL
Series
(847) 843-7500
(847) 843-2798
Low-ESR
tantalum SMT
United Chemi-Con
(847) 696-2000
(Marcon)
(847) 696-9278
Ceramic SMT
TDK
(847) 390-4428
Ceramic SMT
(847) 390-4373
Comments
Cascading Devices
To produce larger negative multiplication of the initial
supply voltage, the MAX660 may be cascaded as
shown in Figure 3. The resulting output resistance is
approximately equal to the sum of the individual
MAX660 ROUT values. The output voltage, where n is
an integer representing the number of devices cascaded, is defined by VOUT = -n (VIN).
Paralleling Devices
Paralleling multiple MAX660s reduces the output resistance. As illustrated in Figure 4, each device requires
its own pump capacitor C1, but the reservoir capacitor
C2 serves all devices. The value of C2 should be
increased by a factor of n, where n is the number of
devices. Figure 4 shows the equation for calculating
output resistance.
ROUT =
ROUT (of MAX660)
n (NUMBER OF DEVICES)
+VIN
+VIN
8
8
8
2
C1
3
4
2
8
2
RL
2
MAX660
"1"
3
C1n
4
5
C1
MAX660
"n"
3
4
5
MAX660
"1"
C1n
3
5
4
MAX660
"n"
5
VOUT
C2n
C2
VOUT = -nVIN
C2
Figure 3. Cascading MAX660s to Increase Output Voltage
8
Figure 4. Paralleling MAX660s to Reduce Output Resistance
_______________________________________________________________________________________
CMOS Monolithic Voltage Converter
This dual function is illustrated in Figure 5. In this circuit, capacitors C1 and C3 perform the pump and
reservoir functions respectively for generation of the
negative voltage. Capacitors C2 and C4 are respectively pump and reservoir for the multiplied positive
voltage. This circuit configuration, however, leads to
higher source impedances of the generated supplies.
This is due to the finite impedance of the common
charge-pump driver.
1M
1M
OPEN-DRAIN
LOW-BATTERY OUTPUT
3V LITHIUM BATTERY
DURACELL DL123A
LBI
3
8
8 IN
2
6
4
5V/100mA
2
150µF
MAX667 LBO 7
MAX660
150µF
OUT
150
µF
DD
1
620k
1M
5
SET 6
GND SHDN
4
5
220k
+VIN
8
NOTE: ALL 150µF CAPACITORS ARE MAXC001, AVAILABLE FROM MAXIM.
D1, D2 = 1N4148
D1
2
MAX660
3
5
4
6
VOUT = -VIN
C1
Figure 6. MAX660 generates a +5V regulated output from a 3V
lithium battery and operates for 16 hours with a 40mA load.
C2
D2
C3
C4
VOUT = (2VIN) (VFD1) - (VFD2)
Figure 5. Combined Positive Multiplier and Negative Converter
_______________________________________________________________________________________
9
MAX660
Combined Positive Supply Multiplication
and Negative Voltage Conversion
MAX660
CMOS Monolithic Voltage Converter
___________________Chip Topography
FC
V+
CAP+
GND
OSC
0.120"
(3.05mm)
LV
CAP-
OUT
0.073"
(1.85mm)
TRANSISTOR COUNT = 89
SUBSTRATE CONNECTED TO V+.
10
______________________________________________________________________________________
CMOS Monolithic Voltage Converter
D
E
DIM
E1
A
A1
A2
A3
B
B1
C
D1
E
E1
e
eA
eB
L
A3
A A2
L A1
0° - 15°
C
e
B1
eA
B
eB
D1
Plastic DIP
PLASTIC
DUAL-IN-LINE
PACKAGE
(0.300 in.)
INCHES
MAX
MIN
0.200
–
–
0.015
0.175
0.125
0.080
0.055
0.022
0.016
0.065
0.045
0.012
0.008
0.080
0.005
0.325
0.300
0.310
0.240
–
0.100
–
0.300
0.400
–
0.150
0.115
PKG. DIM PINS
P
P
P
P
P
N
D
D
D
D
D
D
8
14
16
18
20
24
INCHES
MAX
MIN
0.348 0.390
0.735 0.765
0.745 0.765
0.885 0.915
1.015 1.045
1.14 1.265
MILLIMETERS
MIN
MAX
–
5.08
0.38
–
3.18
4.45
1.40
2.03
0.41
0.56
1.14
1.65
0.20
0.30
0.13
2.03
7.62
8.26
6.10
7.87
2.54
–
7.62
–
–
10.16
2.92
3.81
MILLIMETERS
MIN
MAX
8.84
9.91
18.67 19.43
18.92 19.43
22.48 23.24
25.78 26.54
28.96 32.13
21-0043A
DIM
D
0°-8°
A
0.101mm
0.004in.
e
B
A1
E
C
H
L
Narrow SO
SMALL-OUTLINE
PACKAGE
(0.150 in.)
A
A1
B
C
E
e
H
L
INCHES
MAX
MIN
0.069
0.053
0.010
0.004
0.019
0.014
0.010
0.007
0.157
0.150
0.050
0.244
0.228
0.050
0.016
DIM PINS
D
D
D
8
14
16
MILLIMETERS
MIN
MAX
1.35
1.75
0.10
0.25
0.35
0.49
0.19
0.25
3.80
4.00
1.27
5.80
6.20
0.40
1.27
INCHES
MILLIMETERS
MIN MAX
MIN
MAX
0.189 0.197 4.80
5.00
0.337 0.344 8.55
8.75
0.386 0.394 9.80 10.00
21-0041A
______________________________________________________________________________________
11
MAX660
________________________________________________________Package Information
MAX660
CMOS Monolithic Voltage Converter
___________________________________________Package Information (continued)
DIM
E1
E
D
A
0°-15°
Q
L
L1
e
C
B1
B
S1
S
CERDIP
CERAMIC DUAL-IN-LINE
PACKAGE
(0.300 in.)
A
B
B1
C
E
E1
e
L
L1
Q
S
S1
INCHES
MIN
MAX
–
0.200
0.014
0.023
0.038
0.065
0.008
0.015
0.220
0.310
0.290
0.320
0.100
0.125
0.200
0.150
–
0.015
0.070
–
0.098
0.005
–
DIM PINS
D
D
D
D
D
D
8
14
16
18
20
24
MILLIMETERS
MIN
MAX
–
5.08
0.36
0.58
0.97
1.65
0.20
0.38
5.59
7.87
7.37
8.13
2.54
3.18
5.08
3.81
–
0.38
1.78
–
2.49
0.13
–
INCHES
MILLIMETERS
MIN
MAX MIN MAX
–
0.405
–
10.29
–
0.785
–
19.94
–
0.840
–
21.34
24.38
–
0.960
–
26.92
–
1.060
–
32.51
–
1.280
–
21-0045A
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.
12
____________________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600
© 1996 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
工商网监
湘ICP备2023018690号
