AVAILAB
LE
MAX1044/ICL7660
Switched-Capacitor Voltage Converters
_______________General Description
The MAX1044 and ICL7660 are monolithic, CMOS
switched-capacitor voltage converters that invert, dou-
ble, divide, or multiply a positive input voltage. They are
pin compatible with the industry-standard ICL7660 and
LTC1044. Operation is guaranteed from 1.5V to 10V with
no external diode over the full temperature range. They
deliver 10mA with a 0.5V output drop. The MAX1044
has a BOOST pin that raises the oscillator frequency
above the audio band and reduces external capacitor
size requirements.
The MAX1044/ICL7660 combine low quiescent current
and high efficiency. Oscillator control circuitry and four
power MOSFET switches are included on-chip.
Applications include generating a -5V supply from a
+5V logic supply to power analog circuitry. For applica-
tions requiring more power, the MAX660 delivers up to
100mA with a voltage drop of less than 0.65V.
____________________________Features
♦
Miniature µMAX Package
♦
1.5V to 10.0V Operating Supply Voltage Range
♦
98% Typical Power-Conversion Efficiency
♦
Invert, Double, Divide, or Multiply Input Voltages
♦
BOOST Pin Increases Switching Frequencies
(MAX1044)
♦
No-Load Supply Current: 200µA Max at 5V
♦
No External Diode Required for Higher-Voltage
Operation
______________Ordering Information
PART
MAX1044CPA
MAX1044CSA
MAX1044C/D
MAX1044EPA
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
________________________Applications
-5V Supply from +5V Logic Supply
Personal Communications Equipment
Portable Telephones
Op-Amp Power Supplies
EIA/TIA-232E and EIA/TIA-562 Power Supplies
Data-Acquisition Systems
Hand-Held Instruments
Panel Meters
Ordering Information continued at end of data sheet.
* Contact factory for dice specifications.
_________________Pin Configurations
TOP VIEW
(N.C.) BOOST
CAP+
GND
CAP-
1
2
3
4
8
V+
OSC
LV
V
OUT
Functional Diagrams
__________Typical Operating Circuit
MAX1044
ICL7660
7
6
5
DIP/SO/µMAX
CAP+
V+
INPUT
SUPPLY
VOLTAGE
N.C.
1
V+ AND CASE
8
7
OSC
MAX1044
ICL7660
CAP+
CAP-
V
OUT
GND
NEGATIVE
OUTPUT
VOLTAGE
2
ICL7660
6
LV
GND
3
4
CAP-
5
V
OUT
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
NEGATIVE VOLTAGE CONVERTER
UCSP is a trademark of Maxim Integrated Products, Inc.
( ) ARE FOR ICL7660
TO-99
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-4667; Rev 1; 7/94
MAX1044/ICL7660
Switched-Capacitor Voltage Converters
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V+ to GND, or GND to V
OUT
)....................10.5V
Input Voltage on Pins 1, 6, and 7 .........-0.3V
≤
V
IN
≤
(V+ + 0.3V)
LV Input Current ..................................................................20µA
Output Short-Circuit Duration (V+
≤
5.5V)..................Continuous
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
µMAX (derate 4.1mW/°C above +70°C) ......................330mW
CERDIP (derate 8.00mW/°C above +70°C) .................640mW
TO-99 (derate 6.67mW/°C above +70°C) ....................533mW
Operating Temperature Ranges
MAX1044C_ _ /ICL7660C_ _ ..............................0°C to +70°C
MAX1044E_ _ /ICL7660E_ _ ............................-40°C to +85°C
MAX1044M_ _ /ICL7660M_ _ ........................-55°C to +125°C
Storage Temperature Range ............................-65°C to + 150°C
Lead Temperature (soldering, 10sec) .............................+300°C
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
(Circuit of Figure 1, V+ = 5.0V, LV pin = 0V, BOOST pin = open, I
LOAD
= 0mA, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
R
L
=
∞,
pins 1 and 7
no connection,
LV open
CONDITIONS
T
A
= +25°C
T
A
= 0°C to +70°C
T
A
= -40°C to +85°C
T
A
= -55°C to +125°C
10
3.0
1.5
T
A
= +25°C
T
A
= 0°C to +70°C
T
A
= -40°C to +85°C
T
A
= -55°C to +125°C
Output Resistance
f
OSC
= 2.7kHz (ICL7660)
,
T
A
= +25°C
f
OSC
= 1kHz (MAX1044)
,
T
A
= 0°C to +70°C
V+ = 2V, I
L
= 3mA,
T
A
= -40°C to +85°C
LV to GND
T
A
= -55°C to +125°C
V+ = 5V
C
OSC
= 1pF,
Oscillator Frequency
LV to GND (Note 2)
V+ = 2V
Power Efficiency
R
L
= 5kΩ, T
A
= +25°C, f
OSC
5kHz, LV open
Voltage Conversion Efficiency R
L
=
∞,
T
A
= +25°C, LV open
Pin 1 = 0V
Oscillator Sink or
V
OSC
= 0V or V+, LV open
Source Current
Pin 1 = V+
V+ = 2V
Oscillator Impedance
T
A
= +25°C
V+ = 5V
I
L
= 20mA,
f
OSC
= 5kHz,
LV open
65
10
100
130
130
150
325
325
325
400
5
1
95 98
97.0 99.9
3
20
1.0
100
1.0
100
10
95 98
99.0 99.9
1.5
55
10.0
3.5
100
120
140
150
250
300
300
400
V
MAX1044
MIN TYP MAX
30
200
200
200
200
ICL7660
MIN TYP MAX
80
175
225
250
250
µA
UNITS
Supply Current
R
L
=
∞,
pins 1 and 7 = V+ = 3V
Supply Voltage
Range (Note 1)
R
L
= 10kΩ, LV open
R
L
= 10kΩ, LV to GND
Ω
kHz
%
%
µA
MΩ
kΩ
Note 1:
The Maxim ICL7660 and MAX1044 can operate without an external output diode over the full temperature and voltage
ranges. The Maxim ICL7660 can also be used with an external output diode in series with pin 5 (cathode at V
OUT
) when
replacing the Intersil ICL7660. Tests are performed without diode in circuit.
Note 2:
f
OSC
is tested with C
OSC
= 100pF to minimize the effects of test fixture capacitance loading. The 1pF frequency is correlat-
ed to this 100pF test point, and is intended to simulate pin 7’s capacitance when the device is plugged into a test socket
with no external capacitor. For this test, the LV pin is connected to GND for comparison to the original manufacturer’s
device, which automatically connects this pin to GND for (V+ > 3V).
2
Maxim Integrated
MAX1044/ICL7660
Switched-Capacitor Voltage Converters
__________________________________________Typical Operating Characteristics
(V+ = 5V; C
BYPASS
= 0.1µF; C1 = C2 = 10µF; LV = open; OSC = open; T
A
= +25°C; unless otherwise noted.)
OUTPUT VOLTAGE and OUTPUT RIPPLE
vs. LOAD CURRENT
MAX1044-Fig 1
OUTPUT VOLTAGE and OUTPUT RIPPLE
vs. LOAD CURRENT
MAX1044-Fig 2
OUTPUT VOLTAGE and OUTPUT RIPPLE
vs. LOAD CURRENT
720
OUTPUT RIPPLE (mVp-p)
OUTPUT VOLTAGE (V)
640
-9
-8
-7
-6
-5
-4
-3
-2
-1
A
0
0
5
10
15
20
25
30
35
40
LOAD CURRENT (mA)
0
OUTPUT
RIPPLE
B
C
V+ = 10V
LV = OPEN
OUTPUT
VOLTAGE
A: MAX1044 with
BOOST = V+
B: ICL7660
C: MAX1044 with
BOOST = OPEN
A
B
C
MAX1044-Fig 3
-2.0
OUTPUT
VOLTAGE
OUTPUT VOLTAGE (V)
-1.5
A: MAX1044 with
BOOST = V+
B: ICL7660
C: MAX1044 with
BOOST = OPEN
C
-0.5
B
V+ = 2V
LV = GND
400
350
OUTPUT VOLTAGE (V)
300
250
200
150
100
50
OUTPUT RIPPLE (mVp-p)
-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
A
0
0
5
10
15
B
800
-10
700
630
OUTPUT RIPPLE (mVp-p)
SUPPLY CURRENT (mA)
560
490
420
350
280
210
140
70
OUTPUT VOLTAGE
A
A: MAX1044 with
BOOST = V+
B: ICL7660
C: MAX1044 with
BOOST = OPEN
C
B
560
480
C
400
320
-1.0
V+ = 5V
LV = OPEN
240
160
80
A
0
0
1
2
3
4
5
6
OUTPUT RIPPLE
7
8
9
10
0
OUTPUT RIPPLE
20
25
30
35
40
0
LOAD CURRENT (mA)
LOAD CURRENT (mA)
EFFICIENCY and SUPPLY CURRENT
vs. LOAD CURRENT
MAX1044-Fig 4
EFFICIENCY and SUPPLY CURRENT
vs. LOAD CURRENT
MAX1044-Fig 5
EFFICIENCY and SUPPLY CURRENT
vs. LOAD CURRENT
45
SUPPLY CURRENT (mA)
40
35
30
25
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0
5
10
15
20
25
30
35
40
LOAD CURRENT (mA)
V+ = 10V
LV = OPEN
B, C
A
EFFICIENCY
A: MAX1044 with
BOOST = V+
B: ICL7660
C: MAX1044 with
BOOST = OPEN
SUPPLY CURRENT
MAX1044-Fig 6
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
V+ = 2V
LV = GND
SUPPLY CURRENT
EFFICIENCY
10
9
SUPPLY CURRENT (mA)
8
7
6
5
4
3
2
1
0
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0
5
10
15
20
25
30
35
V+ = 5V
LV = OPEN
A: MAX1044 with
BOOST = V+
B: ICL7660
C: MAX1044 with
BOOST = OPEN
C
EFFICIENCY
A
B
50
100
50
45
40
35
30
25
20
15
10
5
0
SUPPLY CURRENT
20
15
10
5
0
9 10
40
LOAD CURRENT (mA)
LOAD CURRENT (mA)
EFFICIENCY
vs. OSCILLATOR FREQUENCY
MAX1044-Fig 7
OSCILLATOR FREQUENCY
vs. EXTERNAL CAPACITANCE
MAX1044-Fig 8
OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
MAX1044-Fig 9
100
90
EFFICIENCY (%)
80
70
60
50
40
30
10
1
10
2
10
3
10
4
10
5
EXTERNAL
HCMOS
OSCILLATOR
100,000
OSCILLATOR FREQUENCY (Hz)
10,000
1000
100
10
1
0.1
ICL7660 and
MAX1044 with
BOOST = OPEN
MAX1044 with
BOOST -V+
100,000
OSCILLATOR FREQUENCY (Hz)
C1, C2 = 100µF
C1, C2 = 10µF
C1, C2 = 1µF
10,000
1000
6x10
5
100
1
10
100
1000
10,000 100,000
1
2
C
OSC
(pF)
FROM TOP TO BOTTOM AT 5V
MAX1044, BOOST = V+, LV = GND
MAX1044, BOOST = V+, LV = OPEN
ICL7660, LV = GND
ICL7660, LV = OPEN
MAX1044, BOOST = OPEN, LV = GND
MAX1044, BOOST = OPEN, LV = OPEN
3
4
5
6
7
8
9
10
OSCILLATOR FREQUENCY (Hz)
SUPPLY VOLTAGE (V)
Maxim Integrated
3
MAX1044/ICL7660
Switched-Capacitor Voltage Converters
____________________________Typical Operating Characteristics (continued)
(V+ = 5V; C
BYPASS
= 0.1µF; C1 = C2 = 10µF; LV = open; OSC = open; T
A
= +25°C; unless otherwise noted.)
OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX1044-Fig 10
QUIESCENT CURRENT
vs. OSCILLATOR FREQUENCY
MAX1044-Fig 11
100
OSCILLATOR FREQUENCY (kHz)
A: MAX1044 with
BOOST = V+
B: ICL7600
C: MAX1044 with
BOOST = OPEN
10,000
QUIESCENT CURRENT (µA)
80
A
60
1000
100
40
USING
EXTERNAL
CAPACITOR
USING
EXTERNAL
HCMOS
OSCILLATOR
10
1
10
2
10
3
10
4
10
5
5x10
5
20
C
0
-50
B
-25
0
25
50
75
100 125
10
1
10
0
TEMPERATURE (°C)
OSCILLATOR FREQUENCY (Hz)
QUIESCENT CURRENT
vs. SUPPLY VOLTAGE
MAX1044-Fig 12
QUIESCENT CURRENT
vs. TEMPERATURE
400
QUIESCENT CURRENT (µA)
MAX1044-Fig 13
2000
1000
QUIESCENT CURRENT (µA)
A
B
C
D
500
100
300
MAX1044 with
BOOST = V+
10
A: MAX1044, BOOST = V+, LV = GND
B: MAX1044, BOOST = V+, LV = OPEN
C: ICL7660 and MAX1044 with
BOOST = OPEN, LV = GND;
ABOVE 5V, MAX1044 ONLY
D: ICL7660 and MAX1044 with
BOOST = OPEN, LV = OPEN
200
1
100
ICL7660, MAX1044 with BOOST = OPEN
0.1
1
2
0
-50
-25
0
25
50
75
100 125
TEMPERATURE (°C)
3
4
5
6
7
8
9
10
SUPPLY VOLTAGE (V)
OUTPUT RESISTANCE
vs. OSCILLATOR FREQUENCY
MAX1044-Fig 14
OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
MAX1044-Fig 15
OUTPUT RESISTANCE
vs. TEMPERATURE
MAX1044-Fig 16
1000
900
800
RESISTANCE (Ω)
700
C1, C2 = 100µF
EXTERNAL
HCMOS
OSCILLATOR
200
180
OUTPUT RESISTANCE (Ω)
160
140
120
100
80
60
40
20
0
80
70
60
50
40
30
20
-60 -40 -20 0
MAX1044 with
BOOST = V+
ICL7660,
MAX1044 with
BOOST = OPEN
600
500
400
300
200
100
0
10
1
10
2
10
3
FREQUENCY (Hz)
10
4
10
5
1
2
3
4
5
6
7
8
9
10
OUTPUT RESISTANCE (Ω)
C1, C2 = 10µF
C1, C2 = 1µF
20 40 60 80 100 120 140
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
4
Maxim Integrated
MAX1044/ICL7660
Switched-Capacitor Voltage Converters
_____________________________________________________________ Pin Description
PIN
NAME
BOOST
(MAX1044)
1
N.C.
(ICL7660)
2
3
4
5
CAP+
GND
CAP-
V
OUT
No Connection
Connection to positive terminal of Charge-Pump Capacitor
Ground. For most applications, the positive terminal of the reservoir capacitor is connected to this pin.
Connection to negative terminal of Charge-Pump Capacitor
Negative Voltage Output. For most applications, the negative terminal of the reservoir capacitor is
connected to this pin.
Low-Voltage Operation. Connect to ground for supply voltages below 3.5V.
ICL7660: Leave open for supply voltages above 5V.
Oscillator Control Input. Connecting an external capacitor reduces the oscillator frequency. Minimize stray
capacitance at this pin.
Power-Supply Positive Voltage Input. (1.5V to 10V). V+ is also the substrate connection.
FUNCTION
Frequency Boost. Connecting BOOST to V+ increases the oscillator frequency by a factor of six. When the
oscillator is driven externally, BOOST has no effect and should be left open.
6
LV
7
8
OSC
V+
V+
BOOST
V+
C
BYPASS
= 0.1µF
EXTERNAL
OSCILLATOR
OSC
C
OSC
GND
LV
R
L
MAX1044
CAP+
ICL7660
C1
10μF
CAP-
V
OUT
C2
10μF
V
OUT
During the first half of each cycle, switches S1 & S3
close and switches S2 & S4 open, which connects the
bucket capacitor C1 across V+ and charges C1.
During the second half of each cycle, switches S2 & S4
close and switches S1 & S3 open, which connects the
positive terminal of C1 to ground and shifts the nega-
tive terminal to V
OUT
. This connects C1 in parallel with
the reservoir capacitor C2. If the voltage across C2 is
smaller than the voltage across C1, then charge flows
from C1 to C2 until the voltages across them are equal.
During successive cycles, C1 will continue pouring
charge into C2 until the voltage across C2 reaches
- (V+). In an actual voltage inverter, the output is less
than - (V+) since the switches S1–S4 have resistance
and the load drains charge from C2.
Additional qualities of the MAX1044/ICL7660 can be
understood by using a switched-capacitor circuit
model. Switching the bucket capacitor, C1, between
the input and output of the circuit synthesizes a resis-
tance (Figures 3a and 3b.)
When the switch in Figure 3a is in the left position,
capacitor C1 charges to V+. When the switch moves to
the right position, C1 is discharged to V
OUT
. The
charge transferred per cycle is:
ΔQ
= C1(V+ - V
OUT
). If
the switch is cycled at frequency f, then the resulting
Figure 1. Maxim MAX1044/ICL7660 Test Circuit
_______________Detailed Description
The MAX1044/ICL7660 are charge-pump voltage con-
verters. They work by first accumulating charge in a
bucket capacitor and then transfer it into a reservoir
capacitor. The ideal voltage inverter circuit in Figure 2
illustrates this operation.
Maxim Integrated
5
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