MAX681EPD [MAXIM]
+5V to 【10V Voltage Converters; + 5V至± 10V电压转换器
| 型号： | MAX681EPD |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | +5V to 【10V Voltage Converters |
| 文件： | 总8页 (文件大小：86K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-0896; Rev 1; 7/96
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
0/MAX681
________________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ 95% Voltage-Conversion Efficiency
♦ 85% Power-Conversion Efficiency
♦ +2V to +6V Voltage Range
The MAX680/MAX681 a re monolithic , CMOS, d ua l
charge-pump voltage converters that provide ±10V out-
puts from a +5V input voltage. The MAX680/MAX681 pro-
vide both a positive step-up charge pump to develop
+10V from +5V input and an inverting charge pump to
generate the -10V output. Both parts have an on-chip,
8kHz oscillator. The MAX681 has the capacitors internal to
the package, and the MAX680 requires four external
capacitors to produce both positive and negative voltages
from a single supply.
♦ Only Four External Capacitors Required (MAX680)
♦ No Capacitors Required (MAX681)
♦ 500µA Supply Current
♦ Monolithic CMOS Design
The output source impedances are typically 150Ω, pro-
viding useful output currents up to 10mA. The low quies-
cent current and high efficiency make this device suitable
for a variety of applications that need both positive and
negative voltages generated from a single supply.
_______________Ord e rin g In fo rm a t io n
The MAX864/MAX865 are also recommended for new
designs. The MAX864 operates at up to 200kHz and uses
smaller capacitors. The MAX865 comes in the smaller
µMAX package.
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
8 Narrow SO
Dice
MAX680CPA
MAX680CSA
MAX680C/D
MAX680EPA
MAX680ESA
MAX680MJA
MAX681CPD
MAX681EPD
0°C to +70°C
0°C to +70°C
________________________Ap p lic a t io n s
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
8 Plastic DIP
8 Narrow SO
8 CERDIP
The MAX680/MAX681 can be used wherever a single
positive supply is available and where positive and nega-
tive voltages are required. Common applications include
generating ±6V from a 3V battery and generating ±10V
from the standard +5V logic supply (for use with analog
14 Plastic DIP
14 Plastic DIP
-40°C to +85°C
circuitry). Typical applications include:
±6V from 3V Lithium Cell
Hand-Held Instruments
Data-Acquisition Systems
Panel Meters
Battery-Operated
Equipment
_________Typ ic a l Op e ra t in g Circ u it s
Operational Amplifier
Power Supplies
+5V
±10V from +5V Logic
Supply
V
CC
4.7µF
4.7µF
C1+
_________________P in Co n fig u ra t io n s
4.7µF
4.7µF
MAX680
+10V
-10V
GND
V+
V-
C1-
C1+
TOP VIEW
C2-
GND
V+
C1-
C1-
C2+
V
1
2
3
4
5
6
7
CC
14
1
2
3
4
8
7
6
5
V+
C1-
C2+
C2-
V-
GND
+5V
V
13 CC
C1+
MAX680
V
CC
12
11
10
9
V
CC
+10V
V
CC
V+
V-
V
CC
MAX681
FOUR PINS REQUIRED
(MAX681 ONLY)
MAX681
GND
GND
C2-
C2-
V-
V+
-10V
GND
GND
GND
DIP/SO
GND
8
+5V to ±10V CONVERTER
DIP
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
ABSOLUTE MAXIMUM RATINGS
V
CC
................................................................................... +6.2V
Continuous Power Dissipation (T = +70°C)
A
V+ ...................................................................................... +12V
V- ..........................................................................................-12V
V- Short-Circuit Duration ...........................................Continuous
V+ Current ..........................................................................75mA
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) . ....727mW
8-Pin Narrow SO (derate 5.88mW/°C above +70°C) .....471mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C) ..........640mW
14-Pin Plastic DIP (derate 10.00mW/°C above +70°C) ...800mW
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
V
∆V/∆T ..........................................................................1V/µs
CC
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, test circuit Figure 1, T = +25°C, unless otherwise noted.)
CC
A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
6
V
CC
= 3V, T = +25°C, R = ∞
0.5
1
A
L
V
= 5V, T = +25°C, R = ∞
A L
1
2
2.5
3
CC
V
CC
= 5V, 0°C ≤ T ≤ +70°C, R = ∞
A L
Supply Current
mA
V
CC
= 5V, -40°C ≤ T ≤ +85°C, R = ∞
A L
V
CC
= 5V, -55°C ≤ T ≤ +125°C, R = ∞
A L
3
Supply-Voltage Range
MIN ≤ T ≤ MAX, R = 10kΩ
2.0
1.5 to 6.0
150
6.0
250
V
A
L
I + = 10mA, I - = 0mA, V = 5V,
L
L
CC
T
A
= +25°C
I + = 5mA, I - = 0mA, V = 2.8V,
L
L
CC
180
300
Positive Charge-Pump
Output Source Resistance
T
A
= +25°C
Ω
0°C ≤ T ≤ +70°C
325
350
400
A
I + = 10mA,
L
I - = 0mA,
L
-40°C ≤ T ≤ +85°C
A
V
CC
= 5V
-55°C ≤ T ≤ +125°C
A
I - = 10mA, I + = 0mA, V+ = 10V,
L
L
90
150
175
T
A
= +25°C
I - = 5mA, I + = 0mA, V+ = 5.6V,
L
L
110
Negative Charge-Pump
Output Source Resistance
T
A
= +25°C
Ω
0°C ≤ T ≤ +70°C
200
200
250
A
I - = 10mA,
I + = 0mA,
L
V+ = 10V
L
-40°C ≤ T ≤ +85°C
A
-55°C ≤ T ≤ +125°C
A
Oscillator Frequency
Power Efficiency
4
8
kHz
%
R
= 10kΩ
85
99
97
L
V+, R = ∞
95
90
L
Voltage-Conversion
Efficiency
%
V-, R = ∞
L
2
_______________________________________________________________________________________
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
0/MAX681
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(T = +25°C, unless otherwise noted.)
A
OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
OUTPUT VOLTAGE
vs. LOAD CURRENT
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
250
10
9
2.0
1.5
1.0
C1-C4 = 10µF
V- vs. I +
I - = 0
L
L
200
R
+
8
OUT
V+ vs. I +
I - = 0
L
L
150
100
7
R = ∞
L
V+ vs. I -
I + = 0
L
L
6
R
-
OUT
0.5
0
V- vs. I -
I + = 0
L
L
50
0
5
4
3.0
5.0
5
15
3.0
5.0
2.0
4.0
6.0
0
10
20
2.0
4.0
6.0
OUTPUT SOURCE RESISTANCE
vs. TEMPERATURE
OUTPUT RIPPLE vs.
OUTPUT VOLTAGE vs. OUTPUT CURRENT
(FROM V+ TO V-)
OUTPUT CURRENT (I + OR I -)
L
L
200
150
100
200
150
100
10
9
V
CC
= 5V
V
= 5V
CC
V-
MAX680, MAX681
MAX681
V-
V+
R
+
OUT
V+
8
7
R
OUT
-
V+
V-
MAX680
6
C3, C4 = 10µF
50
0
50
0
MAX680
C3, C4 = 100µF
5
4
V+ AND V-
15
20
C1–C4 = 10µF
5
-50 -25
0
25
50
75 100 125
0
10
0
1
2
3
4
5
6
7
8
9
10
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
_______________________________________________________________________________________
3
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
_______________De t a ile d De s c rip t io n
The MAX681 contains all circuitry needed to implement
a dual charge pump. The MAX680 needs only four
c a p a c itors . The s e ma y b e ine xp e ns ive e le c trolytic
capacitors with values in the 1µF to 100µF range. The
MAX681 contains two 1.5µF capacitors as C1 and C2,
and two 2.2µF capacitors as C3 and C4. See Typical
Operating Characteristics.
V
IN
CC
C1
4.7µF
Figure 2a shows the idealized operation of the positive
voltage converter. The on-chip oscillator generates a
50% duty-cycle clock signal. During the first half of the
cycle, switches S2 and S4 are open, S1 and S3 are
closed, and capacitor C1 is charged to the input volt-
MAX680
8
7
1
2
V+ OUT
C1-
V+
I +
L
C2+
C1+
C3
10µF
C2
4.7µF
R +
L
6
5
3
4
C2-
V-
V
CC
age V . During the second half-cycle, S1 and S3 are
CC
op e n, S2 a nd S4 a re c los e d , a nd C1 is tra ns la te d
GND
GND
upward by V volts. Assuming ideal switches and no
6
CC
I -
L
load on C3, charge is transferred onto C3 from C1 such
C4
10µF
R -
L
that the voltage on C3 will be 2V , generating the
CC
positive supply.
V- OUT
Figure 2b shows the negative converter. The switches
of the negative converter are out of phase from the pos-
itive converter. During the second half of the clock
cycle, S6 and S8 are open and S5 and S7 are closed,
charging C2 from V+ (pumped up to 2V by the posi-
tive charge pump) to GND. In the first half of the clock
CC
Figure 1. Test Circuit
a)
b)
V+
V+
S6
S1
C1+ S2
S5
C2+
V
GND
V-
CC
C2
C3
C1
R +
I +
L
L
R -
L
I -
L
C4
S3
S4
S7
S8
V
CC
GND
GND
C1-
C2-
8kHz
Figure 2. Idealized Voltage Quadrupler: a) Positive Charge Pump; b) Negative Charge Pump
4
_______________________________________________________________________________________
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
0/MAX681
cycle, S5 and S7 are open, S6 and S8 are closed, and
________________________Ap p lic a t io n s
the charge on C2 is transferred to C4, generating the
negative supply. The eight switches are CMOS power
MOSFETs . S1, S2, S4, a nd S5 a re P-c ha nne l
s witc he s , while S3, S6, S7, a nd S8 a re N-c ha nne l
switches.
P o s it ive a n d Ne g a t ive Co n ve rt e r
The most common application of the MAX680/MAX681
is as a dual charge-pump voltage converter that pro-
vides positive and negative outputs of two times a posi-
tive input voltage. For applications where PC board
space is at a premium, the MAX681, with its capacitors
internal to the package, offers the smallest footprint.
The simple circuit shown in Figure 3 performs the same
function using the MAX680 with external capacitors C1
and C3 for the positive pump and C2 and C4 for the
negative pump. In most applications, all four capacitors
a re low-c os t, 10µF or 22µF p ola rize d e le c trolytic s .
When using the MAX680 for low-current applications,
1µF can be used for C1 and C2 charge-pump capaci-
tors, and 4.7µF for C3 and C4 reservoir capacitors.
C1 and C3 must be rated at 6V or greater, and C2 and
C4 must be rated at 12V or greater.
__________Effic ie n c y Co n s id e ra t io n s
Theoretically, a charge-pump voltage multiplier can
approach 100% efficiency under the following con-
ditions:
• The charge-pump switches have virtually no offset
and extremely low on-resistance
• Minimal power is consumed by the drive circuitry
• The impedances of the reservoir and pump capaci-
tors are negligible
For the MAX680/MAX681, the energy loss per clock
cycle is the sum of the energy loss in the positive and
negative converters as below:
LOSS
= LOSS
+ LOSS
POS NEG
TOT
=
1⁄2 C1 (V+)2 – (V+)(VCC
)
[
] +
1⁄2 C2 (V+)2 – (V-)2
[
]
There will be a substantial voltage difference between
(V+ - V ) a nd V for the p os itive p ump , a nd
CC
CC
between V+ and V-, if the impedances of pump capaci-
tors C1 and C2 are high relative to their respective out-
put loads.
C1
22µF
MAX680
8
7
1
2
V+ OUT
C1-
V+
Larger C3 and C4 reservoir capacitor values reduce
output ripple. Larger values of both pump and reservoir
capacitors improve efficiency.
C2+
C1+
C3
22µF
C2
22µF
6
5
3
4
V
CC
IN
C2-
V-
V
CC
________Ma x im u m Op e ra t in g Lim it s
GND
GND
The MAX680/MAX681 have on-chip zener diodes that
C4
22µF
clamp V
to approximately 6.2V, V+ to 12.4V, and
CC
V- to -12.4V. Never exceed the maximum supply volt-
a g e : e xc e s s ive c urre nt ma y b e s hunte d b y the s e
diodes, potentially damaging the chip. The MAX680/
MAX681 operate over the entire operating temperature
range with an input voltage of +2V to +6V.
V- OUT
Figure 3. Positive and Negative Converter
_______________________________________________________________________________________
5
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
22µF
22µF
22µF
22µF
MAX680
MAX680
8
7
8
7
1
2
1
2
V+ OUT
C1-
C1-
V+
V+
C2+
C1+
C2+
C1+
22µF
22µF
6
5
6
5
3
4
3
4
V
CC
IN
C2-
V-
C2-
V-
V
CC
V
CC
GND
GND
GND
0/MAX681
V- OUT
Figure 4. Paralleling MAX680s For Lower Source Resistance
The MAX680/MAX681 are not voltage regulators: the
outp ut s ourc e re s is ta nc e of e ithe r c ha rg e p ump is
The positive output voltage will be:
V+ = 2V – V
+
CC
DROP
approximately 150Ω at room temperature with V
at
CC
The negative output voltage will be:
5V. Under light load with an input V
of 5V, V+ will
CC
approach +10V and V- will be at -10V. However both,
V+ and V- will droop toward GND as the current drawn
from either V+ or V- increases, since the negative con-
verter draws its power from the positive converter’s out-
put. To predict output voltages, treat the chips as two
separate converters and analyze them separately. First,
V- = (V+ - V
) = - (2V - V
+ - V
-)
DROP
CC
DROP
DROP
The positive and negative charge pumps are tested
and specified separately to provide the separate values
of output source resistance for use in the above formu-
las. When the positive charge pump is tested, the neg-
ative charge pump is unloaded. When the negative
charge pump is tested, the positive supply V+ is from
a n e xte rna l s ourc e , is ola ting the ne g a tive c ha rg e
pump.
the droop of the negative supply (V
) equals the
DROP-
current drawn from V- - (I -) times the source resistance
L
of the negative converter (RS-):
V
- = I - x RS-
L
DROP
Calculate the ripple voltage on either output by noting
that the current drawn from the output is supplied by
the reservoir capacitor alone during one half-cycle of
the clock. This results in a ripple of:
Likewise, the positive supply droop (V
the current drawn from the positive supply (I +) times
the p os itive c onve rte r’s s ourc e re s is ta nc e (RS+ ),
except that the current drawn from the positive supply
is the sum of the current drawn by the load on the posi-
+) equals
L
DROP
1
1
1
V
= ⁄ IOUT ( ⁄ f
)( ⁄ CR)
RIPPLE
PUMP
2
For the nomina l f
of 8kHz with 10µF re s e rvoir
PUMP
tive supply (I +) plus the current drawn by the negative
L
capacitors, the ripple will be 30mV with I
at 5mA.
OUT
converter (I -):
L
Re me mb e r tha t in mos t a p p lic a tions , the p os itive
charge pump’s I is the load current plus the current
(V
+) = I + x RS+ = (I + + I -) x RS+
L L L
DROP
OUT
taken by the negative charge pump.
6
_______________________________________________________________________________________
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
0/MAX681
no external setting resistors, minimizing part count. The
combined quiescent current of the MAX680/MAX681,
MAX663, and MAX664 is less than 500µA, while the out-
put current capability is 5mA. The MAX680/MAX681
input can vary from 3V to 6V without affecting regulation
appreciably. With higher input voltage, more current can
be drawn from the MAX680/MAX681 outputs. With 5V at
P a ra lle lin g De vic e s
Paralleling multiple MAX680/MAX681s reduces the out-
put resistance of both the positive and negative con-
verters. The effective output resistance is the output
resistance of a single device divided by the number of
devices. As Figure 4 shows, each MAX680 requires
s e p a ra te p ump c a p a c itors C1 a nd C2, b ut a ll c a n
share a single set of reservoir capacitors.
V
, 10mA can be drawn from both regulated outputs
CC
simultaneously. Assuming 150Ω source resistance for
both converters, with (I + + I -) = 20mA, the positive
±5 V Re g u la t e d S u p p lie s fro m
a S in g le 3 V Ba t t e ry
Figure 5 shows a complete ±5V power supply using one
3V battery. The MAX680/MAX681 provide +6V at V+,
which is regulated to +5V by the MAX666, and -6V,
which is regulated to -5V by the MAX664. The MAX666
and MAX664 are pretrimmed at wafer sort and require
L
L
charge pump will droop 3V, providing +7V for the nega-
tive charge pump. The negative charge pump will droop
another 1.5V due to its 10mA load, leaving -5.5V at V-
sufficient to maintain regulation for the MAX664 at this
current.
LOW-BATTERY
WARNING AT 3.5V
LBO
LBI
SENSE
2MΩ
MAX666
100µF
+12V TO +6V
V
CC
+5V
VIN
VOUT
1.2MΩ
6V TO 3V
100µF
GND SDN VSET
MAX680
C1+
0.1µF
10µF
10µF
V+
C1-
GND
C2+
100µF
V-
0.1µF
C2-
GND SDN
MAX664
V
SET
GND
100µF
V
IN
-12V TO -6V
VOUT1
VOUT2
SENSE
-5V
Figure 5. Regulated +5V and -5V from a Single Battery
_______________________________________________________________________________________
7
+5 V t o ±1 0 V Vo lt a g e Co n ve rt e rs
___________________Ch ip To p o g ra p h y
C1-
V+
+
C2+
0. 116"
(2. 95mm)
0/MAX681
C2-
V-
GND
0. 72"
(1. 83mm)
________________________________________________________P a c k a g e In fo rm a t io n
INCHES
MILLIMETERS
DIM
MIN
0.053
MAX
0.069
0.010
0.019
0.010
0.157
MIN
1.35
0.10
0.35
0.19
3.80
MAX
1.75
0.25
0.49
0.25
4.00
A
D
A1 0.004
B
C
E
e
0.014
0.007
0.150
0°-8°
A
0.101mm
0.004in.
0.050
1.27
e
H
L
0.228
0.016
0.244
0.050
5.80
0.40
6.20
1.27
A1
C
B
L
INCHES
MILLIMETERS
DIM PINS
Narrow SO
SMALL-OUTLINE
PACKAGE
MIN MAX
MIN
MAX
5.00
8.75
8
0.189 0.197 4.80
D
D
D
E
H
14 0.337 0.344 8.55
16 0.386 0.394 9.80 10.00
(0.150 in.)
21-0041A
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
© 1989 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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