19-1305; Rev 3; 11/10
Switched-Capacitor Voltage Doublers
General Description
The ultra-small MAX1682/MAX1683 monolithic, CMOS
charge-pump voltage doublers accept input voltages
ranging from +2.0V to +5.5V. Their high voltage-con-
version efficiency (over 98%) and low operating current
(110µA for MAX1682) make these devices ideal for
both battery-powered and board-level voltage-doubler
applications.
Oscillator control circuitry and four power MOSFET
switches are included on-chip. The MAX1682 operates
at 12kHz, and the MAX1683 operates at 35kHz. A typi-
cal application includes generating a 6V supply to
power an LCD display in a hand-held PDA. Both parts
are available in a 5-pin SOT23 package and can deliver
30mA with a typical voltage drop of 600mV.
____________________________Features
♦
5-Pin SOT23 Package
♦
+2.0V to +5.5V Input Voltage Range
♦
98% Voltage-Conversion Efficiency
♦
110µA Quiescent Current (MAX1682)
♦
Requires Only Two Capacitors
♦
Up to 45mA Output Current
MAX1682/MAX1683
________________________Applications
Small LCD Panels
Cell Phones
Handy-Terminals
PDAs
PART
Ordering Information
TEMP
RANGE
PIN-
PACKAGE
SOT
TOP MARK
MAX1682EUK+T
-40°C to +85°C 5 SOT23-5
ACCL
MAX1683EUK+T
-40°C to +85°C 5 SOT23-5
ACCM
Note:
These parts are available in tape-and-reel only. Minimum
order quantity is 2500 pieces.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Typical Operating Circuit
5
C1+
IN
4
V
IN
INPUT
SUPPLY
VOLTAGE
Pin Configuration
C1
MAX1682
MAX1683
3
C1-
TOP VIEW
GND
1
OUT
2
OUTPUT
VOLTAGE
2 x V
IN
C2
C1-
3
4
IN
5
C1+
OUT
2
MAX1682
MAX1683
1
GND
VOLTAGE DOUBLER
SOT23-5
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Switched-Capacitor Voltage Doublers
MAX1682/MAX1683
ABSOLUTE MAXIMUM RATINGS
IN to GND .................................................................+6V to -0.3V
OUT to GND .......................................................+12V, V
IN
- 0.3V
OUT Output Current............................................................50mA
Output Short-Circuit Duration .................................1sec (Note 1)
Continuous Power Dissipation (T
A
= +70°C)
SOT23-5 (derate 7.1mW/°C above +70°C)...................571mW
Operating Temperature Range
MAX1682EUK/MAX1683EUK ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
Soldering Temperature (reflow) .......................................+260°C
Note 1:
Avoid shorting OUT to GND, as it may damage the device. For temperatures above +85°C, shorting OUT to GND even
instantaneously will damage the device.
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
IN
= +5.0V, capacitor values from Table 2, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
No-Load Supply Current
Supply Voltage Range
Minimum Operating Voltage
Oscillator Frequency
Output Resistance
Voltage Conversion Efficiency
T
A
= +25°C
R
LOAD
= 10kΩ
(Note 2)
T
A
= +25°C
I
OUT
= 5mA
I
OUT
= 0mA, T
A
= +25°C
MAX1682
MAX1683
T
A
= +25°C
T
A
= 0°C to +85°C
98
99.9
8.4
24.5
CONDITIONS
MAX1682
MAX1683
T
A
= +25°C
T
A
= 0°C to +85°C
2.0
2.1
MIN
TYP
110
230
1.7
1.8
1
12
35
20
15.6
45.5
50
65
MAX
145
310
5.5
5.5
UNITS
µA
V
V
kHz
Ω
%
Note 2:
Once started, the MAX1682/MAX1683 typically operate down to 1V.
ELECTRICAL CHARACTERISTICS
(V
IN
= +5.0V, capacitor values from Table 2, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 3)
PARAMETER
No-Load Supply Current
Supply Voltage Range
Oscillator Frequency
Output Resistance
Voltage Conversion Efficiency
MAX1682
MAX1683
R
LOAD
= 10kΩ
MAX1682
MAX1683
I
OUT
= 5mA
I
OUT
= 0mA
97
2.3
6.6
17.5
CONDITIONS
MIN
TYP
MAX
160
350
5.5
18.6
57.8
65
UNITS
µA
V
kHz
Ω
%
Note 3:
Specifications at -40°C to +85°C are guaranteed by design.
2
_______________________________________________________________________________________
Switched-Capacitor Voltage Doublers
Typical Operating Characteristics
(Typical Operating Circuit, V
IN
= +5V, C1 = C2 = 10µF for the MAX1682 and 3.3µF for the MAX1683, T
A
= +25°C, unless otherwise
noted.)
OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
80
OUTPUT RESISTANCE (Ω)
70
60
50
MAX1682, C1 = C2 = 10μF
40
30
20
MAX1683, C1 = C2 = 10μF
10
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
V
IN
(V)
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
MAX1683, C1 = C2 = 3.3μF
MAX1682/83 TOC1
MAX1682/MAX1683
MAX1682 OUTPUT RESISTANCE
vs. TEMPERATURE
MAX1682/83 TOC02
MAX1683 OUTPUT RESISTANCE
vs. TEMPERATURE
35
OUTPUT RESISTANCE (Ω)
30
25
20
15
V
IN
= 5V
10
5
I
LOAD
= 5mA
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
V
IN
= 3.3V
MAX1682/83 TOC03
90
40
35
OUTPUT RESISTANCE (Ω)
30
25
20
15
10
5
I
LOAD
= 5mA
V
IN
= 5V
V
IN
= 3.3V
V
IN
= 2V
40
V
IN
= 2V
MAX1682 OUTPUT RESISTANCE
vs. CAPACITANCE
MAX1682/83 TOC4
MAX1683 OUTPUT RESISTANCE
vs. CAPITANCE
MAX1682/83 TOC05
MAX1682
OUTPUT VOLTAGE RIPPLE
vs. OUTPUT CURRENT
700
600
V
RIPPLE
(mV)
500
400
300
200
100
0
C1 = C2 = 10μF
C1 = C2 = 33μF
C1 = C2 = 3.3μF
MAX1682/83 TOC06
120
100
OUTPUT RESISTANCE (Ω)
80
60
V
IN
= 2V
40
20
0
0
5
10
V
IN
= 5V
15
20
V
IN
= 3.3V
25
30
50
45
OUTPUT RESISTANCE (Ω)
40
35
30
25
20
15
10
5
0
V
IN
= 5V
V
IN
= 3.3V
V
IN
= 2V
800
35
0
5
10
15
20
25
30
35
0
5
10
15
20
I
OUT
(mA)
25
30
35
40
CAPACITANCE (μF)
CAPACITANCE (μF)
MAX1683
OUTPUT VOLTAGE RIPPLE
vs. OUTPUT CURRENT
900
800
700
V
RIPPLE
(mV)
600
500
400
300
200
100
0
0
5
10
15
20
I
OUT
(mA)
25
30
35
40
0
C1 = C2 = 10μF
C1 = C2 = 3.3μF
C1 = C2 =1μF
MAX1682/83 TOC07
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1682/83 TOC09
1000
300
250
SUPPLY CURRENT (μA)
200
150
100
50
MAX1683
MAX1682
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
3
Switched-Capacitor Voltage Doublers
MAX1682/MAX1683
Typical Operating Characteristics (continued)
(Typical Operating Circuit, V
IN
= +5V, C1 = C2 = 10µF for the MAX1682 and 3.3µF for the MAX1683, T
A
= +25°C, unless otherwise
noted.)
MAX1682 OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX1682/83 TOC10
MAX1683 OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX1682/83 TOC11
MAX1682 OUTPUT VOLTAGE
vs. OUTPUT CURRENT
9
8
OUTPUT VOLTAGE (V)
7
6
5
4
3
2
1
V
IN
= 2V
V
IN
= 3.3V
V
IN
= 5V
MAX1682/83 TOC12
12.5
OSCILLATOR FREQUENCY (kHz)
40
OSCILLATOR FREQUENCY (kHz)
38
V
IN
= 5V
36
34
32
30
28
V
IN
= 3.3V
V
IN
= 2V
10
V
IN
= 5V
12.0
V
IN
= 3.3V
11.5
V
IN
= 2V
11.0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0
-40
-20
0
20
40
60
80
0
5
10 15 20 25 30 35 40 45 50
OUTPUT CURRENT (mA)
TEMPERATURE (°C)
MAX1683 OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX1682/83 TOC13
MAX1682 EFFICIENCY vs.
LOAD CURRENT
MAX1682/83 TOC14
MAX1683 EFFICIENCY vs.
LOAD CURRENT
98
96
EFFICIENCY (%)
94
92
90
88
86
84
82
80
V
IN
= 2V
V
IN
= 3.3V
V
IN
= 5V
MAX1682/83 TOC15
10
9
8
OUTPUT VOLTAGE (V)
7
6
5
4
3
2
1
0
0
5
V
IN
= 2V
V
IN
= 3.3V
V
IN
= 5V
100
98
96
EFFICIENCY (%)
94
92
90
88
86
84
82
80
V
IN
= 2V
V
IN
= 3.3V
V
IN
= 5V
100
10 15 20 25 30 35 40 45 50
OUTPUT CURRENT (mA)
0
5
10
15
20
25
30
0
5
10
15
20
25
30
LOAD CURRENT (mA)
LOAD CURRENT (mA)
MAX1682
OUTPUT RIPPLE
MAX1682toc16
MAX1683
OUTPUT RIPPLE
MAX1682toc17
START-UP VOLTAGE
vs. RESISTIVE LOAD
MAX1683
2.0
MAX1682toc18
2.5
V
OUT
20mV/div
V
OUT
20mV/div
V
START
(V)
1.5
MAX1682
1.0
0.5
0
20μs/div
I
LOAD
= 5mA, V
IN
= 5V, C1 = C2 = 10μF
20μs/div
I
LOAD
= 5mA, V
IN
= 5V, C1 = 3.3μF, C2 = 10μF
700 300 100 70 30 10
7
3
1
0.7 0.3
R
LOAD
(kΩ)
4
_______________________________________________________________________________________
Switched-Capacitor Voltage Doublers
_____________________Pin Description
PIN
1
2
3
4
5
NAME
GND
OUT
C1-
IN
C1+
Ground
Doubled Output Voltage. Connect C2
between OUT and GND.
Negative Terminal of the Flying
Capacitor
Input Supply
Positive Terminal of the Flying
Capacitor
FUNCTION
Efficiency Considerations
The power efficiency of a switched-capacitor voltage
converter is affected by three factors: the internal losses
in the converter IC, the resistive losses of the capacitors,
and the conversion losses during charge transfer
between the capacitors. The total power loss is:
ΣP
LOSS
=
P
INTERNAL LOSSES
+
P
PUMP CAPACITOR LOSSES
+
P
CONVERSION LOSSES
The internal losses are associated with the IC’s internal
functions, such as driving the switches, oscillator, etc.
These losses are affected by operating conditions such
as input voltage, temperature, and frequency.
The next two losses are associated with the voltage
converter circuit’s output resistance. Switch losses
occur because of the on-resistance of the MOSFET
switches in the IC. Charge-pump capacitor losses
occur because of their ESR. The relationship between
these losses and the output resistance is as follows:
P
PUMP CAPACITOR LOSSES
+
P
SWITCH LOSSES
=
I
OUT
R
OUT
≅
x R
OUT
1
+
2R
SWITCHES
+
4ESR
C1
f
OSC
x C1
2
MAX1682/MAX1683
_______________Detailed Description
The MAX1682/MAX1683 capacitive charge pumps
double the voltage applied to their input. Figure 1
shows a simplified functional diagram of an ideal volt-
age doubler. During the first half-cycle, switches S1
and S2 close, and capacitor C1 charges to V
IN
. During
the second half cycle, S1 and S2 open, S3 and S4
close, and C1 is level shifted upward by V
IN
volts. This
connects C1 to the reservoir capacitor C2, allowing
energy to be delivered to the output as necessary. The
actual voltage is slightly lower than 2 x V
IN
, since
switches S1–S4 have resistance and the load drains
charge from C2.
(
)
Charge-Pump Output
The MAX1682/MAX1683 have a finite output resistance
of about 20Ω (Table 2). As the load current increases,
the devices’ output voltage (V
OUT
) droops. The droop
equals the current drawn from V
OUT
times the circuit’s
output impedance (R
S
), as follows:
V
DROOP
= I
OUT
x R
S
V
OUT
= 2 x V
IN
- V
DROOP
+
ESR
C2
where f
OSC
is the oscillator frequency. The first term is
the effective resistance from an ideal switched-
capacitor circuit (Figures 2a and 2b).
f
V+
V
OUT
C2
C1
R
L
S1
V
IN
C1
S3
Figure 2a. Switched-Capacitor Model
V
OUT
C2
R
EQUIV
V+
1
R
EQUIV
=
f
×
C1
V
IN
C2
R
L
V
OUT
S2
S4
Figure 1. Simplified Functional Diagram of Ideal Voltage
Doubler
Figure 2b. Equivalent Circuit
5
_______________________________________________________________________________________
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