_______________General Description
The MAX764/MAX765/MAX766 inverting switching regu-
lators are highly efficient over a wide range of load cur-
rents, delivering up to 1.5W. A unique, current-limited,
pulse-frequency-modulated (PFM) control scheme com-
bines the benefits of traditional PFM converters with the
benefits of pulse-width-modulated (PWM) converters.
Like PWM converters, the MAX764/MAX765/MAX766 are
highly efficient at heavy loads. Yet because they are PFM
devices, they use less than 120µA of supply current (vs.
2mA to 10mA for a PWM device).
The input voltage range is 3V to 16V. The output volt-
age is preset at -5V (MAX764), -12V (MAX765), or -15V
(MAX766); it can also be adjusted from -1V to -16V
using two external resistors (Dual Mode
TM
). The maxi-
mum operating V
IN
- V
OUT
differential is 20V.
These devices use miniature external components; their
high switching frequencies (up to 300kHz) allow for less
than 5mm diameter surface-mount magnetics. A stan-
dard 47µH inductor is ideal for most applications, so no
magnetics design is necessary.
An internal power MOSFET makes the MAX764/MAX765/
MAX766 ideal for minimum component count, low- and
medium-power applications. For increased output drive
capability or higher output voltages, use the
MAX774/MAX775/MAX776 or MAX1774, which drive an
external power P-channel MOSFET for loads up to 5W.
________________________Applications
LCD-Bias Generators
Portable Instruments
LAN Adapters
Remote Data-Acquisition Systems
Battery-Powered Applications
____________________________Features
o
High Efficiency for a Wide Range of Load Currents
o
250mA Output Current
o
120µA Max Supply Current
o
5µA Max Shutdown Current
o
3V to 16V Input Voltage Range
o
-5V (MAX764), -12V (MAX765), -15V (MAX766),
or Adjustable Output from -1V to -16V
o
Current-Limited PFM Control Scheme
o
300kHz Switching Frequency
o
Internal, P-Channel Power MOSFET
______________Ordering Information
Ordering Information continued on last page.
* Dice are tested at T
A
= +25°C, DC parameters only.
**Contact factory for availability and processing to MIL-STD-883.
MAX764/MAX765/MAX766
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
________________________________________________________________
Maxim Integrated Products
1
1
2
3
4
8
7
6
5
LX
V+
V+
GND
REF
SHDN
FB
OUT
MAX764
MAX765
MAX766
DIP/SO
TOP VIEW
__________________Pin Configuration
GND
MAX764
SHDN
LX
OUT
ON/OFF
REF
47µH
OUTPUT
-5V
INPUT
3V TO 15V
V+
FB
__________Typical Operating Circuit
Call toll free 1-800-998-8800 for free samples or literature.
19-0176; Rev 0; 6/94
PART
MAX764
CPA
MAX764CSA
MAX764C/D
0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
MAX764EPA
MAX764ESA
-40°C to +85°C
-40°C to +85°C
8 Plastic DIP
8 SO
MAX764MJA
-55°C to +125°C
8 CERDIP**
MAX765
CPA
MAX765CSA
MAX765C/D
0°C to +70°C
0°C to +70°C
0°C to +70°C
8 Plastic DIP
8 SO
Dice*
MAX765EPA
MAX765ESA
-40°C to +85°C
-40°C to +85°C
8 Plastic DIP
8 SO
MAX765MJA
-55°C to +125°C
8 CERDIP**
Evaluation Kit
Available
MAX764/MAX765/MAX766
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = 5V, I
LOAD
= 0mA, C
REF
= 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°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.
V+ to GND ..............................................................-0.3V to +17V
OUT to GND ...........................................................+0.5V to -17V
Maximum Differential (V+ to OUT) ......................................+21V
REF, SHDN, FB to GND ...............................-0.3V to (V+ + 0.3V)
LX to V+..................................................................+0.3V to -21V
LX Peak Current ...................................................................1.5A
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
CERDIP (derate 8.00mW/°C above +70°C) .................640mW
Operating Temperature Ranges
MAX76_C_A ........................................................0°C to +70°C
MAX76_E_A .....................................................-40°C to +85°C
MAX76_MJA ..................................................-55°C to +125°C
Maximum Junction Temperatures
MAX76_C_A/E_A ..........................................................+150°C
MAX76_MJA .................................................................+175°C
Storage Temperature Range ............................-65°C to +160°C
Lead Temperature (soldering, 10sec) ............................+300°C
3V
V+
16V
V+ = 16V, SHDN = 0V or V+
V+ = 16V, SHDN < 0.4V
4V
V+
6V
0mA
I
LOAD
100mA
MAX76_M
3V
V+
16V
MAX76_C/E
0µA
I
REF
100µA
MAX76_M
MAX765C/E, -11.52V
V
OUT
12.48V
MAX764, -4.8V
V
OUT
5.2V
MAX76_E
MAX76_C
MAX76_M
MAX76_E
V+ = 16V, SHDN > 1.6V
V+ = 10V, SHDN > 1.6V
3V
V+
16V
MAX766, -14.40V
V
OUT
-15.60V
MAX76_C
MAX765M, -11.52V
V
OUT
12.48V
CONDITIONS
V
1.6
V
IH
SHDN Input Voltage High
µA
±1
SHDN Leakage Current
80
%/V
0.12
Line Regulation (Note 2)
%/mA
0.008
Load Regulation (Note 2)
µV/V
40
100
REF Line Regulation
4
15
mV
4
10
REF Load Regulation
1.4550
1.5
1.5450
1.4625
1.5
1.5375
V
1.4700
1.5
1.5300
V
REF
Reference Voltage
35
105
50
120
µA
90
120
I
S
Supply Current
3.5
V+
V
3.0
16.0
V+ Input Voltage Range
68
120
mA
150
260
I
OUT
Output Current and Voltage
(Note 1)
±90
±70
2
I
SHDN
Shutdown Current
1
5
mV
-10
10
FB Trip Point
nA
±50
I
FB
FB Input Current
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
MAX76_C/E
MAX76_M
V
OUT
= -5V
82
V
OUT
= -15V
Efficiency (Note 2)
10mA
I
LOAD
100mA,
V
IN
= 5V
%
3V
V+
16V
V
0.4
V
IL
SHDN Input Voltage Low
MAX764/MAX765/MAX766
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
_______________________________________________________________________________________
3
Note 1:
See Maximum Output Current vs. Supply Voltage graph in the
Typical Operating Characteristics. Guarantees are based on
correlation to switch on-time, switch off-time, on-resistance, and peak current rating.
Note 2:
Circuit of Figure 2.
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, I
LOAD
= 0mA, C
REF
= 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
I
V
OUT
I
+ (V+)
10V
I
LX
I
+ (V+)
20V
I
V
OUT
I
+ (V+)
10V
CONDITIONS
µs
1.8
2.3
2.8
t
OFF
Minimum Switch Off-Time
µs
12
16
20
t
ON
Maximum Switch On-Time
A
0.5
0.75
I
PEAK
Peak Current at LX
±30
±10
µA
±5
LX Leakage Current
1.4
2.5
LX On-Resistance
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
MAX76_C
MAX76_E
MAX76_M
__________________________________________Typical Operating Characteristics
(V+ = 5V, V
OUT
= -5V, T
A
= +25°C, unless otherwise noted.)
100
0
0.1
10
1000
MAX764
EFFICIENCY vs. LOAD CURRENT
MAX764-01
LOAD CURRENT (mA)
EFFICIENCY (%)
90
80
70
60
50
40
30
20
10
1
100
CIRCUIT OF FIGURE 2
V
OUT
= -5V ±4%
V+ = 5V
V+ = 10V
V+ = 15V
100
0
0.1
10
1000
MAX765
EFFICIENCY vs. LOAD CURRENT
MAX764-02
LOAD CURRENT (mA)
EFFICIENCY (%)
90
80
70
60
50
40
30
20
10
1
100
V+ = 8V
V+ = 5V
CIRCUIT OF FIGURE 2
V
OUT
= -12V ±4%
100
0
0.1
10
1000
MAX766
EFFICIENCY vs. LOAD CURRENT
MAX764-03
LOAD CURRENT (mA)
EFFICIENCY (%)
90
80
70
60
50
40
30
20
10
1
100
V+ = 5V
CIRCUIT OF FIGURE 2
V
OUT
= -15V ±4%
MAX764/MAX765/MAX766
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
4
_______________________________________________________________________________________
____________________________Typical Operating Characteristics (continued)
(V+ = 5V, V
OUT
= -5V, T
A
= +25°C, unless otherwise noted.)
0
-60
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX764 -07
TEMPERATURE (°C)
SHUTDOWN CURRENT (
µ
A)
-40 -20
0
20 40 60 80 100 120 140
V+ = 15V
0.5
1.0
1.5
2.0
2.5
3.0
4.0
3.5
V+ = 8V
V+ = 4V
15.0
-60
MAXIMUM SWITCH ON-TIME
vs. TEMPERATURE
MAX764 -08
TEMPERATURE (°C)
MAXIMUM SWITCH ON-TIME (
µ
s)
-40 -20
0
20 40 60 80 100 120 140
V+ = 15V
V+ = 5V
15.2
15.4
15.6
15.8
16.0
16.2
16.4
16.6
16.8
17.0
2.20
-60
MINIMUM SWITCH OFF-TIME
vs. TEMPERATURE
MAX764 -09
TEMPERATURE (°C)
MINIMUM SWITCH OFF-TIME (
µ
s)
-40 -20
0
20 40 60 80 100 120 140
2.25
2.30
2.35
2.40
2.45
2.50
2.60
2.55
V+ = 5V
V+ = 15V
6.2
-60
SWITCH ON/OFF-TIME RATIO
vs. TEMPERATURE
MAX764 -10
TEMPERATURE (°C)
SWITCH ON/OFF-TIME RATIO (
µ
s/
µ
s)
-40 -20
0
20 40 60 80 100 120 140
V+ = 5V
6.3
6.4
6.5
6.6
6.7
6.8
6.9
7.0
7.1
7.2
0
START-UP SUPPLY VOLTAGE
vs. OUTPUT CURRENT
MAX764 -11
OUTPUT CURRENT (mA)
START-UP SUPPLY VOLTAGE (V)
0
1
2
3
4
5
6
8
7
50
100
150
200
250
300
CIRCUIT OF FIGURE 2
10,000
1
20
LX LEAKAGE CURRENT
vs. TEMPERATURE
10
100
MAX764-12
TEMPERATURE (°C)
LX LEAKAGE CURRENT (nA)
1000
30 40 50 60 70 80 90 100 110 120 130
I
V
OUT
I
+ (V+) = 20V
MAXIMUM OUTPUT CURRENT
vs. SUPPLY VOLTAGE
MAX764 -04
SUPPLY VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (mA)
3
600
4 5 6
7 8 9 10 11 12 13 14 15 16
500
400
300
200
100
0
V
OUT
= -5V
V
OUT
= -12V
V
OUT
= -15V
CIRCUIT OF FIGURE 2
60
NO-LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX764 -05
SUPPLY VOLTAGE (V)
NO-LOAD SUPPLY CURRENT (
µ
A)
3
65
70
75
80
85
90
100
95
4 5 6
7 8 9 10 11 12 13 14 15 16
50
-60
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
55
MAX764 -06
TEMPERATURE (°C)
NO-LOAD SUPPLY CURRENT (
µ
A)
-40 -20
0
20 40 60 80 100 120 140
60
65
70
75
80
85
90
95
100
105
110
V+ = 15V
V+ = 5V
MAX764/MAX765/MAX766
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
_______________________________________________________________________________________
5
1000
0.01
0
2
4
6
10
12
14
8
16
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
0.1
MAX764-17
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
1
10
100
I
LOAD
= 100mA
I
LOAD
= 0mA
CIRCUIT OF FIGURE 2
-60
REFERENCE OUTPUT RESISTANCE
vs. TEMPERATURE
MAX764 -15
TEMPERATURE (°C)
REFERENCE OUTPUT RESISTANCE (
)
-40 -20
0
20 40 60 80 100 120 140
0
50
100
150
200
250
I
REF
= 10
µ
A
I
REF
= 50
µ
A
I
REF
= 100
µ
A
____________________________Typical Operating Characteristics (continued)
(V+ = 5V, V
OUT
= -5V, T
A
= +25°C, unless otherwise noted.)
0.8
-60
LX ON-RESISTANCE
vs. TEMPERATURE
MAX764 -13
TEMPERATURE (°C)
LX ON-RESISTANCE (
)
-40 -20
0
20 40 60 80 100 120 140
I
V
OUT
I
+ (V+) = 10V
1.0
1.2
1.4
1.6
1.8
2.0
2.2
I
V
OUT
I
+ (V+) = 15V
I
V
OUT
I
+ (V+) = 20V
-60
PEAK CURRENT AT LX
vs. TEMPERATURE
MAX764
-
14
TEMPERATURE (°C)
CURRENT AT LX (A)
-40 -20
0
20 40 60 80 100 120 140
0.65
0.70
0.75
0.80
0.85
0.90
0.95
I
V
OUT
I
+ (V+) = 20V
I
V
OUT
I
+ (V+) = 15V
I
V
OUT
I
+ (V+) = 10V
-60
REFERENCE OUTPUT
vs. TEMPERATURE
MAX764 -16
TEMPERATURE (°C)
REFERENCE OUTPUT (V)
-40 -20
0
20 40 60 80 100 120 140
1.506
1.504
1.502
1.500
1.498
1.496
1.494
1.492
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