_______________General Description
The MAX864 CMOS, charge-pump, DC-DC voltage
converter produces a positive and a negative output
from a single positive input, and requires only four
capacitors. The charge pump first doubles the input
voltage, then inverts the doubled voltage. The input
voltage ranges from +1.75V to +6.0V.
The internal oscillator can be pin-programmed from
7kHz to 185kHz, allowing the quiescent current, capac-
itor size, and switching frequency to be optimized. The
55
output impedance permits useful output currents
up to 20mA. The MAX864 also has a 1A logic-con-
trolled shutdown.
The MAX864 comes in a 16-pin QSOP package that
uses the same board area as a standard 8-pin SOIC.
For more space-sensitive applications, the MAX865 is
available in an 8-pin MAX package, which uses half
the board area of the MAX864.
________________________Applications
Low-Voltage GaAsFET Bias in Wireless Handsets
VCO and GaAsFET Supply
Split Supply from 2 to 4 Ni Cells or 1 Li+ Cell
Low-Cost Split Supply for Low-Voltage
Data-Acquisition Systems
Split Supply for Analog Circuitry
LCD Panels
____________________________Features
o
Requires Only Four Capacitors
o
Dual Outputs (Positive and Negative)
o
Low Input Voltages: +1.75V to +6.0V
o
1A Logic-Controlled Shutdown
o
Selectable Frequencies Allow Optimization
of Capacitor Size and Supply Current
MAX864
Dual-Output Charge Pump with Shutdown
________________________________________________________________
Maxim Integrated Products
1
MAX864
C1+
IN
V+
V-
SHDN
FC1
GND
FC0
C1-
C2+
V
IN
V
IN
V
IN
C2-
+2V
IN
V
IN
(+1.75V TO +6.0V)
-2V
IN
__________________Pin Configuration
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
C1+
V+
N.C.
N.C.
IN
GND
N.C.
N.C.
C1-
C2+
GND
C2-
V-
SHDN
FC1
FC0
TOP VIEW
MAX864
QSOP
__________Typical Operating Circuit
19-0478; Rev 0; 3/96
PART
MAX864C/D
MAX864EEE
-40C to +85C
0C to +70C
TEMP. RANGE
PIN-PACKAGE
Dice*
16 QSOP
______________Ordering Information
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
*
Contact factory for dice specifications.
MAX864
Dual-Output Charge Pump with Shutdown
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS (Note 1)
(V
IN
= 5V,
SHDN = V
IN
, circuit of Figure 1, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
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.
Note 1:
Measured using the capacitor values in Table 1. Capacitor ESR contributes approximately 10% of the output impedance
[ESR + 1 / (pump frequency x capacitance)].
V+ to GND ..............................................................-0.3V to +12V
SHDN, FC0, FC1 to GND .............................-0.3V to (V+ + 0.3V)
IN to GND ..............................................................-0.3V to +6.2V
V- to GND ...............................................................+0.3V to -12V
V- Output Current .............................................................100mA
V- Short Circuit to GND .................................................Indefinite
Operating Temperature Range
MAX864EEE......................................................-40C to +85C
Continuous Power Dissipation (T
A
= +70C)
QSOP (derate 8.70mW/C above +70C) .....................696mW
Storage Temperature Range ............................ -65C to +160C
Lead Temperature (soldering, 10sec) .............................+300C
60
V+ = 10V, I
V-
= 10mA (forced)
Output Resistance
(Note 1)
34
50
100
I
V+
= 10mA, I
V-
= 0mA
55
75
6
50
I
V-
= 10mA
V- to GND Shutdown Resistance
22
100
I
V+
= 10mA
V+ to IN Shutdown Resistance
A
-1
1
SHDN, FC0 = FC1 = GND or IN
Logic Input Bias Current
V
3.5
2.8
SHDN, FC0, FC1
Logic Input High Voltage
V
2.2
1.0
SHDN, FC0, FC1
Logic Input Low Voltage
kHz
130
185
260
FC1 = FC0 = IN
Oscillator Frequency
V
6.0
R
LOAD
= 10k
Maximum Supply Voltage
V
2.00
Minimum Start-Up Voltage
70
100
140
FC1 = IN, FC0 = GND
24
33
48
FC1 = GND, FC0 = IN
5
7
10
FC1 = FC0 = GND
A
0.1
1
FC1 = FC0 = IN or GND,
SHDN = GND
Shutdown Current
0.6
1.0
FC1 = FC0 = GND, f = 7kHz
2.4
3.65
FC1 = GND, FC0 = IN, f = 33kHz
7
11
FC1 = IN, FC0 = GND, f = 100kHz
mA
12
18
FC1 = FC0 = IN, f = 185kHz
Supply Current
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
R
LOAD
= 10k
%
95
99
V-, R
L
=
Voltage Conversion Efficiency
95
99
V+, R
L
=
T
A
= T
MIN
to T
MAX
T
A
= +25C
T
A
= +25C
T
A
= T
MIN
to T
MAX
SUPPLY
INPUTS AND OUTPUTS
T
A
= +25C
T
A
= T
MIN
to T
MAX
1.75
1.25
__________________________________________Typical Operating Characteristics
(V
IN
= 5.0V, capacitor values in Table 1, T
A
= +25C, unless otherwise noted.)
10
-10
0
5
10
20
25
40
OUTPUT VOLTAGE
vs. OUTPUT CURRENT
-8
6
8
MAX864-07
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
15
30
35
-2
4
2
0
-4
-6
V- LOADED
C1C4 = 1
F
V
IN
= 4.75V
FC1 = 1
FC0 = 1 (185kHz)
V- LOADED
V+ LOADED
V+ LOADED
BOTH V+ AND
V- LOADED EQUALLY
100
0
0
10
5
20
35
EFFICIENCY vs. OUTPUT CURRENT
@ 7kHz PUMP FREQUENCY
20
80
V+
V-
V-
90
MAX864-01
OUTPUT CURRENT (mA)
EFFICIENCY V+, V- (
%
)
15
25
30
70
40
60
50
30
10
V
IN
= 5.0V
V
IN
= 3.3V
C1C4 = 33
F
FC1 = 0, FC0 = 0
V+
0
0
10
5
20
35
EFFICIENCY vs. OUTPUT CURRENT
@ 33kHz PUMP FREQUENCY
20
80
V+
V-
V-
90
MAX864-02
OUTPUT CURRENT (mA)
EFFICIENCY V+, V- (
%
)
15
25
30
70
40
60
50
30
10
V
IN
= 5.0V
V
IN
= 3.3V
V+
C1C4 = 6.8
F
FC1 = 0, FC0 = 1
0
0
10
5
20
35
EFFICIENCY vs. OUTPUT CURRENT
@ 100kHz PUMP FREQUENCY
20
80
V+
V-
V-
MAX864-03
OUTPUT CURRENT (mA)
EFFICIENCY V+, V- (
%
)
15
25
30
70
40
60
50
30
10
V
IN
= 5.0V
V+
V
IN
= 3.3V
C1C4 = 2.2
F
FC1 = 0, FC0 = 0
0
0
10
5
20
35
EFFICIENCY vs. OUTPUT CURRENT
@ 185kHz PUMP FREQUENCY
20
80
V+
V-
V-
MAX864-04
OUTPUT CURRENT (mA)
EFFICIENCY V+, V- (
%
)
15
25
30
70
40
60
50
30
10
V
IN
= 5.0V
V+
V
IN
= 3.3V
C1C4 = 1
F
FC1 = 1, FC0 = 1
160
40
1.0
2.0
4.0
6.0
OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
60
140
MAX864-05
SUPPLY VOLTAGE (V)
OUTPUT RESISTANCE (
)
3.0
5.0
100
120
80
R
OUT-
FC1 = 1, FC0 = 1
(185kHz @ 5V)
R
OUT+
140
35
-55 -35 -15
45
65
125
OUTPUT RESISTANCE
vs. TEMPERATURE
50
125
MAX864-06
TEMPERATURE (C)
OUTPUT RESISTANCE (
)
5
25
85 105
80
110
95
65
V-, V
IN
= 3.0V
V-, V
IN
= 4.5V
V+, V
IN
= 3.0V
V+, V
IN
= 4.5V
4.5
0
0
5
10 15
30
25
35
50
OUTPUT CURRENT vs. PUMP CAPACITANCE
(V
IN
= 1.9V, V+ +
V-
= 6V)
0.5
3.5
4.0
MAX864-08
PUMP CAPACITANCE (
F)
OUTPUT CURRENT FROM V+ TO V- (mA)
20
40 45
2.0
3.0
2.5
1.5
1.0
f = 7kHz
C1 = C2 = C3 = C4
f = 33kHz
f = 185kHz
f = 100kHz
9
0
0
5
10 15
30
25
35
50
OUTPUT CURRENT vs. PUMP CAPACITANCE
(V
IN
= 3.15V, V+ +
V-
= 10V)
1
7
8
MAX864-09
PUMP CAPACITANCE (
F)
OUTPUT CURRENT FROM V+ TO V- (mA)
20
40 45
4
6
5
3
2
C1 = C2 = C3 = C4
f = 185kHz
f = 7kHz
f = 33kHz
f = 100kHz
MAX864
Dual-Output Charge Pump with Shutdown
_______________________________________________________________________________________
3
MAX864
Dual-Output Charge Pump with Shutdown
4
_______________________________________________________________________________________
____________________________Typical Operating Characteristics (continued)
(V
IN
= 5.0V, capacitor values in Table 1, T
A
= +25C, unless otherwise noted.)
14
0
0
5
10 15
30
25
35
50
OUTPUT CURRENT vs. PUMP CAPACITANCE
(V
IN
= 4.75V, V+ +
V-
= 16V)
2
12
MAX864-10
PUMP CAPACITANCE (
F)
OUTPUT CURRENT FROM V+ TO V- (mA)
20
40 45
6
10
8
4
185kHz
100kHz
7kHz
33kHz
C1 = C2 = C3 = C4
400
0
0
5
10 15
30
25
35
50
OUTPUT VOLTAGE RIPPLE
vs. PUMP CAPACITANCE
(V
IN
= 1.9V, V+ +
V-
= 6V)
50
350
MAX864-11
PUMP CAPACITANCE (
F)
OUTPUT VOLTAGE RIPPLE (mVp-p)
20
40 45
200
150
300
250
100
7kHz
33kHz
100kHz
185kHz
C1 = C2 = C3 = C4
OUTPUT RIPPLE IS
MEASURED FOR THE
LOAD CURRENT INDICATED
IN THE "OUTPUT CURRENT
vs. PUMP CAPACITANCE"
GRAPH AT V
IN
= 1.9V.
600
0
0
5
10 15
30
25
35
50
OUTPUT VOLTAGE RIPPLE
vs. PUMP CAPACITANCE
(V
IN
= 3.15V, V+ +
V-
= 10V)
500
MAX864-12
PUMP CAPACITANCE (
F)
OUTPUT VOLTAGE RIPPLE (mVp-p)
20
40 45
300
200
400
100
7kHz
33kHz
100kHz
185kHz
C1 = C2 = C3 = C4
OUTPUT RIPPLE IS
MEASURED FOR THE
LOAD CURRENT INDICATED
IN THE "OUTPUT CURRENT
vs. PUMP CAPACITANCE"
GRAPH AT V
IN
= 3.15V.
800
0
0
5
10 15
30
25
35
50
OUTPUT VOLTAGE RIPPLE
vs. PUMP CAPACITANCE
(V
IN
= 4.75V, V+ +
V-
= 16V)
700
MAX864-13
PUMP CAPACITANCE (
F)
OUTPUT VOLTAGE RIPPLE (mVp-p)
20
40 45
400
300
200
600
500
100
7kHz
100kHz
33kHz
185kHz
C1 = C2 = C3 = C4
OUTPUT RIPPLE IS
MEASURED FOR THE
LOAD CURRENT INDICATED
IN THE "OUTPUT CURRENT
vs. PUMP CAPACITANCE"
GRAPH AT V
IN
= 4.75V.
600
0
1.0
2.0
4.0
6.0
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
500
MAX864-14
SUPPLY VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT (nA)
3.0
5.0
300
200
400
100
3.0
0
-55
-15
-35
65
45
85
125
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
2.5
MAX864-15
TEMPERATURE (C)
SHUTDOWN SUPPLY CURRENT (
A)
25
5
105
1.5
1.0
2.0
0.5
V
IN
= 5.0V
V
IN
= 3.3V
7
0
-55
-15
-35
65
45
85
125
SUPPLY CURRENT vs. TEMPERATURE
(V
IN
= 3.3V)
6
MAX864-16
TEMPERATURE (C)
SUPPLY CURRENT (mA)
25
5
105
3
2
5
4
1
FC1 = 1, FC0 = 1
FC1 = 1, FC0 = 0
FC1 = 0, FC0 = 1
FC1 = 0, FC0 = 0
14
0
-55
-15
-35
65
45
85
125
SUPPLY CURRENT vs. TEMPERATURE
(V
IN
= 5V)
12
MAX864-17
TEMPERATURE (C)
SUPPLY CURRENT (mA)
25
5
105
6
4
10
8
2
FC1 = 1, FC0 = 1
FC1 = 1, FC0 = 0
FC1 = 0, FC0 = 1
FC1 = 0, FC0 = 0
200
0
-55
-15
-35
65
45
85
125
PUMP FREQUENCY
vs. TEMPERATURE
180
MAX864-18
TEMPERATURE (C)
PUMP FREQUENCY (kHz)
25
5
105
100
80
60
160
140
120
20
40
FC1 = 1, FC0 = 1
FC1 = 1, FC0 = 0
FC1 = 0, FC0 = 1
FC1 = 0, FC0 = 0
MAX864
Dual-Output Charge Pump with Shutdown
_______________________________________________________________________________________
5
____________________________Typical Operating Characteristics (continued)
(V
IN
= 5.0V, capacitor values in Table 1, T
A
= +25C, unless otherwise noted.)
TIME TO EXIT SHUTDOWN
+5V
0V
+10V
0V
-10V
MAX864-19
1ms/div
FC0 = FC1 = IN (185kHz), C1C4 = 1
F
FC0 = FC1 = GND (7kHz), C1C4 = 33
F
_____________________Pin Description
No Connect--no internal connection.
Connect these to ground to improve
thermal dissipation.
N.C.
9, 10,
13, 14
Positive Power-Supply Input
IN
12
Output of the Boost Charge Pump
V+
15
Positive Terminal of the Flying Boost
Capacitor
C1+
16
Output of the Inverting Charge Pump
V-
5
Active-Low Shutdown Input. With
SHDN low, the part is in shutdown
mode and its supply current is less
than 1A. In shutdown mode, V+
connects to IN through a 22
switch,
and V- connects to GND through a
6
switch.
SHDN
6
Frequency Select, MSB (see Table 1)
FC1
7
Frequency Select, LSB (see Table 1)
FC0
8
Negative Terminal of the Flying
Inverting Capacitor
C2-
4
Ground (connect pins 3 and 11 together)
GND
3, 11
PIN
Positive Terminal of the Flying
Inverting Capacitor
C2+
2
Negative Terminal of the Flying Boost
Capacitor
C1-
1
FUNCTION
NAME
MAX864
C1+
1
2
3
4
5
6
7
8
C1-
16
15
14
13
12
11
10
9
C2
+5V
C1
C3
C4
V
CC
IN
C2+
C2-
GND
V-
SHDN
FC0
FC1
V+ OUT
V- OUT
SEE TABLE 1 FOR CAPACITOR VALUES.
R
L-
R
L+
I
L+
V+
N.C.
N.C.
IN
GND
N.C.
N.C.
I
L-
Figure 1. Test Circuit
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