MAX1682EUK-T [MAXIM]
Switched-Capacitor Voltage Doublers; 开关电容电压倍增器
| 型号： | MAX1682EUK-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Switched-Capacitor Voltage Doublers |
| 文件： | 总8页 (文件大小：85K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1305; Rev 1; 8/98
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
2/MAX1683
Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ 5-Pin SOT23 Package
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.
♦ +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
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-
c a l a pp lic a tion inc lud e s ge ne ra ting a 6V supp ly 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.
Ord e rin g In fo rm a t io n
________________________Ap p lic a t io n s
Small LCD Panels
TEMP.
RANGE
PIN-
SOT
PART
PACKAGE TOP MARK
Cell Phones
MAX1682C/D
0°C to +70°C Dice*
—
ACLL
—
Handy-Terminals
PDAs
MAX1682EUK-T -40°C to +85°C 5 SOT23-5
MAX1683C/D 0°C to +70°C Dice*
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.
*Dice are tested at T = +25°C.
A
Typ ic a l Op e ra t in g Circ u it
INPUT
SUPPLY
VOLTAGE
5
4
V
IN
IN
C1+
P in Co n fig u ra t io n
C1
MAX1682
MAX1683
TOP VIEW
3
1
C1-
GND
OUT
C1-
1
2
3
5
4
C1+
IN
OUTPUT
VOLTAGE
2
OUT
MAX1682
MAX1683
2 x V
IN
C2
GND
SOT23-5
VOLTAGE DOUBLER
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
ABSOLUTE MAXIMUM RATINGS
IN to GND.................................................................+6V to -0.3V
Operating Temperature Range
OUT to GND.......................................................+12V, V - 0.3V
OUT Output Current............................................................50mA
Output Short-Circuit Duration .................................1sec (Note 1)
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
IN
Continuous Power Dissipation (T = +70°C)
A
SOT23-5 (derate 7.1mW/°C above +70°C)...................571mW
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 = +5.0V, capacitor values from Table 2, T = 0°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.)
IN
A
A
PARAMETER
CONDITIONS
MAX1682
MAX1683
MIN
TYP
MAX UNITS
110
230
1.7
1.8
1
145
µA
2/MAX1683
No-Load Supply Current
T = +25°C
A
310
T
A
= +25°C
2.0
2.1
5.5
V
Supply Voltage Range
Minimum Operating Voltage
Oscillator Frequency
R
= 10kΩ
LOAD
T
A
= 0°C to +85°C
5.5
(Note 2)
= +25°C
V
MAX1682
MAX1683
8.4
12
15.6
kHz
45.5
T
A
24.5
35
T
= +25°C
20
50
Ω
A
Output Resistance
I
= 5mA
OUT
T
A
= 0°C to +85°C
65
Voltage Conversion Efficiency
I
= 0mA, T = +25°C
98
99.9
%
OUT
A
Note 2: Once started, the MAX1682/MAX1683 typically operate down to 1V.
ELECTRICAL CHARACTERISTICS
(V = +5.0V, capacitor values from Table 2, T = -40°C to +85°C, unless otherwise noted.) (Note 3)
IN
A
PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
MAX1682
MAX1683
160
µA
No-Load Supply Current
Supply-Voltage Range
Oscillator Frequency
350
R
= 10kΩ
2.3
6.6
5.5
18.6
57.8
65
V
LOAD
MAX1682
MAX1683
kHz
17.5
Output Resistance
I
= 5mA
= 0mA
Ω
OUT
Voltage Conversion Efficiency
I
97
%
OUT
Note 3: Specifications at -40°C to +85°C are guaranteed by design.
2
_______________________________________________________________________________________
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
2/MAX1683
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(Typical Operating Circuit, V = +5V, C1 = C2 = 10µF for the MAX1682 and 3.3µF for the MAX1683, T = +25°C, unless otherwise
IN
A
noted.)
OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
MAX1682 OUTPUT RESISTANCE
vs. TEMPERATURE
MAX1683 OUTPUT RESISTANCE
vs. TEMPERATURE
90
80
70
60
50
40
30
20
10
40
35
30
25
20
15
10
5
40
35
30
25
20
15
10
5
V
IN
= 2V
V
V
= 2V
IN
MAX1683, C1 = C2 = 3.3µF
MAX1682, C1 = C2 = 10µF
V
IN
= 3.3V
= 3.3V
IN
V
= 5V
IN
V
= 5V
IN
I
= 5mA
LOAD
MAX1683, C1 = C2 = 10µF
I
= 5mA
LOAD
0
0
-40
-20
0
20
40
60
80
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
V
IN
(V)
TEMPERATURE (°C)
MAX1682
MAX1682 OUTPUT RESISTANCE
vs. CAPACITANCE
OUTPUT VOLTAGE RIPPLE
vs. OUTPUT CURRENT
MAX1683 OUTPUT RESISTANCE
vs. CAPITANCE
800
700
600
500
400
300
200
100
0
120
100
80
60
40
20
0
50
45
40
35
30
25
20
15
10
5
V
IN
= 2V
C1 = C2 = 3.3µF
V
IN
= 3.3V
V
IN
= 2V
C1 = C2 = 10µF
C1 = C2 = 33µF
V
IN
= 5V
V
= 5V
V
= 3.3V
30
IN
IN
0
0
5
10
15
20
25
35
0
5
10
15
20
25
30
35
0
5
10 15 20 25 30 35 40
(mA)
CAPACITANCE (µF)
CAPACITANCE (µF)
I
OUT
MAX1683
OUTPUT VOLTAGE RIPPLE
vs. OUTPUT CURRENT
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
1000
900
800
700
600
500
400
300
200
100
0
300
250
200
150
100
50
C1 = C2 =1µF
MAX1683
C1 = C2 = 3.3µF
C1 = C2 = 10µF
MAX1682
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
0
5
10 15 20 25 30 35 40
I
(mA)
OUT
_______________________________________________________________________________________
3
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(Typical Operating Circuit, V = +5V, C1 = C2 = 10µF for the MAX1682 and 3.3µF for the MAX1683, T = +25°C, unless otherwise
IN
A
noted.)
MAX1682 OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX1682 OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX1683 OSCILLATOR FREQUENCY
vs. TEMPERATURE
10
9
8
7
6
5
4
3
2
1
0
12.5
40
38
36
34
32
30
28
V
IN
= 5V
V
IN
= 5V
V
IN
= 5V
12.0
V
IN
= 3.3V
V
IN
= 3.3V
V
IN
= 2V
11.5
V
IN
= 3.3V
V
IN
= 2V
60
V
IN
= 2V
0
11.0
0
5
10 15 20 25 30 35 40 45 50
OUTPUT CURRENT (mA)
-40
-20
20
40
60
80
-40
-20
0
20
40
80
2/MAX1683
TEMPERATURE (°C)
TEMPERATURE (°C)
MAX1683 EFFICIENCY vs.
LOAD CURRENT
MAX1683 OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX1682 EFFICIENCY vs.
LOAD CURRENT
10
9
8
7
6
5
4
3
2
1
0
100
98
96
94
92
90
88
86
84
82
80
100
98
96
94
92
90
88
86
84
82
80
V
IN
= 5V
V
IN
= 5V
V
IN
= 5V
V
IN
= 3.3V
V = 2V
IN
V
IN
= 2V
V
IN
= 3.3V
V
IN
= 3.3V
V
IN
= 2V
0
5
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)
MAX1683
OUTPUT RIPPLE
MAX1682
OUTPUT RIPPLE
START-UP VOLTAGE
vs. RESISTIVE LOAD
2.5
2.0
1.5
1.0
0.5
0
MAX1683
V
V
OUT
OUT
20mV/div
20mV/div
MAX1682
20µs/div
20µs/div
700 300 100 70 30 10
7
3
1
0.7 0.3
R
LOAD
(kΩ)
I
= 5mA, V = 5V, C1 = C2 = 10µF
I
= 5mA, V = 5V, C1 = 3.3µF, C2 = 10µF
LOAD
IN
LOAD IN
4
_______________________________________________________________________________________
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
2/MAX1683
Effic ie n c y Co n s id e ra t io n s
_____________________P in De s c rip t io n
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,
a nd the c onve rs ion los s e s d uring c ha rg e tra ns fe r
between the capacitors. The total power loss is:
PIN
NAME
FUNCTION
1
GND
Ground
Doubled Output Voltage. Connect C2
between OUT and GND.
2
OUT
ΣP
= P
INTERNAL LOSSES
LOSS
Negative Terminal of the Flying
Capacitor
+ P
PUMP CAPACITOR LOSSES
CONVERSION LOSSES
3
4
5
C1-
IN
+ P
Input Supply
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.
Positive Terminal of the Flying
Capacitor
C1+
_______________De t a ile d De s c rip t io n
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
s witc he s in the IC. Cha rg e -p ump c a p a c itor los s e s
occur because of their ESR. The relationship between
these losses and the output resistance is as follows:
The MAX1682/MAX1683 c a p a c itive c ha rg e p ump s
d oub le the volta g e a p p lie d to the ir inp ut. Fig ure 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 . During
IN
the second half cycle, S1 and S2 open, S3 and S4
P
+ P
=
PUMP CAPACITOR LOSSES
SWITCH LOSSES
close, and C1 is level shifted upward by V volts. This
IN
connects C1 to the reservoir capacitor C2, allowing
energy to be delivered to the output as necessary. The
2
I
x R
OUT
OUT
1
a c tua l volta g e is s lig htly lowe r tha n 2 x V , s inc e
switches S1–S4 have resistance and the load drains
charge from C2.
IN
R
+ 2R
+ 4ESR
SWITCHES C1
OUT
f
x C1
(
)
C2
OSC
+ ESR
Ch a rg e -P u m p Ou t p u t
The MAX1682/MAX1683 have a finite output resistance
of about 20Ω (Table 2). As the load current increases,
where f
is the oscillator frequency. The first term is
the e ffe c tive re s is ta nc e from a n id e a l s witc he d -
capacitor circuit (Figures 2a and 2b).
OSC
the devices’ output voltage (V ) droops. The droop
OUT
equals the current drawn from V
times the circuit’s
OUT
f
output impedance (R ), as follows:
S
V
= I
x R
V+
DROOP
OUT
S
V
OUT
V
OUT
= 2 x V - V
IN
DROOP
C2
R
L
C1
S1
S3
V
IN
Figure 2a. Switched-Capacitor Model
C1
V
OUT
R
EQUIV
C2
V+
V
OUT
S2
S4
1
R
EQUIV
=
C2
f × C1
R
L
V
IN
Figure 2b. Equivalent Circuit
Figure 1. Simplified Functional Diagram of Ideal Voltage
Doubler
_______________________________________________________________________________________
5
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
Conversion losses occur during the charge transfer
between C1 and C2 when there is a voltage difference
between them. The power loss is:
Us ing a la rg e r flying c a p a c itor re d uc e s the outp ut
impedance and improves efficiency (see the Efficiency
Considerations section). Above a certain point, increas-
ing C1’s capacitance has a negligible effect because
the output resistance becomes dominated by the inter-
na l s witc h re s is ta nc e a nd c a p a c itor ESR (s e e the
Outp ut Re s is ta nc e vs . Ca p a c ita nc e g ra p h in the
Typical Operating Characteristics). Table 2 lists the
most desirable capacitor values—those that produce a
low output resistance. But when space is a constraint, it
may be necessary to sacrifice low output resistance for
the sake of small capacitor size. Table 3 demonstrates
how the capacitor affects output resistance.
2
2
P
=
1/ C1 4V
IN
− V
OUT
+
CONVERSION LOSS
2
2
1/ C2 2V
V
− V
x f
OSC
RIPPLE
2
OUT RIPPLE
where V
is the peak-to-peak output voltage ripple
RIPPLE
determined by the output capacitor and load current
(see Output Capacitor section). Choose capacitor val-
ues that decrease the output resistance (see Flying
Capacitor section).
Ou t p u t Ca p a c it o r (C2 )
Increasing the output capacitance reduces the output
ripple voltage. Decreasing its ESR reduces both output
resistance and ripple. Smaller capacitance values can
be used with light loads. Use the following equation to
calculate the peak-to-peak ripple:
Ap p lic a t io n s In fo rm a t io n
Flyin g Ca p a c it o r (C1 )
To maintain the lowest output resistance, use capaci-
tors with low ESR. Suitable capacitor manufacturers are
listed in Table 1. The charge-pump output resistance is
a function of C1 and C2’s ESR and the internal switch
2/MAX1683
V
= I
/ (f
x C2) + 2 x I x ESR
OUT C2
RIPPLE
OUT
OSC
In p u t Byp a s s Ca p a c it o r
resistance, as shown in the equation for R
Efficiency Considerations section.
in the
OUT
Bypass the incoming supply to reduce its AC imped-
a nc e a nd the imp a c t of the MAX1682/MAX1683’s
switching noise. When loaded, the circuit draws a con-
Minimizing the charge-pump capacitor’s ESR mini-
mizes the total resistance. Suggested values are listed
in Tables 2 and 3.
tinuous current of 2 x I . A 0.1µF bypass capacitor is
OUT
sufficient.
Table 1. Recommended Capacitor Manufacturers
PRODUCTION METHOD
MANUFACTURER
SERIES
PHONE
FAX
AVX
Matsuo
Sprague
AVX
TPS
267
803-946-0690
714-969-2491
603-224-1961
803-946-0590
714-969-2491
803-448-2170
714-960-6492
603-224-1430
803-626-3123
714-960-6492
Surface-Mount Tantalum
593D, 595D
X7R
Surface-Mount Ceramic
Matsuo
X7R
Table 3. Suggested Capacitor Values for
Minimum Size
Table 2. Suggested Capacitor Values for
Low Output Resistance
FREQUENCY CAPACITOR
TYPICAL
FREQUENCY CAPACITOR
TYPICAL
PART
PART
(kHz)
VALUE (µF)
R
OUT
(Ω)
(kHz)
VALUE (µF)
R
OUT
(Ω)
MAX1682
MAX1683
12
35
10
20
MAX1682
MAX1683
12
35
3.3
1
35
3.3
20
35
6
_______________________________________________________________________________________
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
2/MAX1683
Ca s c a d in g De vic e s
Devices can be cascaded to produce an even larger
voltage (Figure 3). The unloaded output voltage is nom-
P a ra lle lin g De vic e s
Paralleling multiple MAX1682 or MAX1683s reduces
the output resistance. Each device requires its own
pump capacitor (C1), but the reservoir capacitor (C2)
serves all devices (Figure 4). Increase C2’s value by a
factor of n, where n is the number of parallel devices.
Fig ure 4 shows the e qua tion for c a lc ula ting output
resistance.
inally (n + 1) x V , where n is the number of voltage
IN
doublers used. This voltage is reduced by the output
resistance of the first device multiplied by the quiescent
current of the second. The output resistance increases
when devices are cascaded. Using a two-stage dou-
bler as an example, output resistance can be approxi-
La yo u t a n d Gro u n d in g
Good layout is important, primarily for good noise per-
formance. To ensure good layout, mount all compo-
nents as close together as possible, keep traces short
to minimize parasitic inductance and capacitance, and
use a ground plane.
mated as R
the output resistance of the first stage and R
output resistance of the second stage. A typical value
for a two-stage voltage doubler is 60Ω (with C1 at 10µF
for MAX1682 and 3.3µF for MAX1683). For n stages
with the same C1 value, R
= 2 x R
+ R
, where R
is
is the
OUT
OUT1
OUT2
OUT1
OUT2
n
= (2 - 1) x R
.
OUT
OUT1
INPUT
SUPPLY
VOLTAGE
INPUT
SUPPLY
VOLTAGE
C1+
IN
IN
C1+
IN
IN
C1+
C1+
MAX1682
MAX1683
MAX1682
MAX1683
MAX1682
MAX1683
MAX1682
MAX1683
GND
GND
C1-
GND
GND
C1
C1
C1
C1
OUTPUT
VOLTAGE
OUTPUT
VOLTAGE
OUT
C1-
OUT
C1-
OUT
C2
C1-
OUT
C2
R
OF SINGLE DEVICE
OUT
R
OUT
=
C2
NUMBER OF DEVICES
Figure 3. Cascading Devices
Figure 4. Paralleling Devices
_______________________________________________________________________________________
7
S w it c h e d -Ca p a c it o r Vo lt a g e Do u b le rs
___________________Ch ip In fo rm a t io n
TRANSISTOR COUNT: 97
SUBSTRATE CONNECTED TO OUT
________________________________________________________P a c k a g e In fo rm a t io n
2/MAX1683
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.
8 _____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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