19-0176; Rev 0; 6/94
Kit
tion e
lua
l
Eva vailab
A
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
____________________________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
_______________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.
MAX764/MAX765/MAX766
______________Ordering Information
PART
MAX764CPA
MAX764CSA
MAX764C/D
MAX764EPA
MAX764ESA
MAX764MJA
MAX765CPA
MAX765CSA
MAX765C/D
MAX765EPA
MAX765ESA
MAX765MJA
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP**
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP**
________________________Applications
LCD-Bias Generators
Portable Instruments
LAN Adapters
Remote Data-Acquisition Systems
Battery-Powered Applications
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.
__________Typical Operating Circuit
INPUT
3V TO 15V
V+
LX
__________________Pin Configuration
TOP VIEW
OUTPUT
-5V
OUT
FB
1
2
8
LX
V+
V+
GND
MAX764
ON/OFF
SHDN
47µH
SHDN
3
REF
4
MAX764
MAX765
MAX766
7
6
5
REF
FB
GND
OUT
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
MAX764/MAX765/MAX766
ABSOLUTE MAXIMUM RATINGS
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
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, 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.)
PARAMETER
V+ Input Voltage Range
Supply Current
Shutdown Current
FB Trip Point
FB Input Current
I
FB
SYMBOL
V+
I
S
I
SHDN
MAX76_C/E
MAX76_M
V+ = 16V, SHDN < 0.4V
V+ = 16V, SHDN > 1.6V
V+ = 10V, SHDN > 1.6V
3V
≤
V+
≤
16V
MAX76_C
MAX76_E
MAX76_M
MAX764, -4.8V
≤
V
OUT
≤
5.2V
Output Current and Voltage
(Note 1)
I
OUT
MAX765C/E, -11.52V
≤
V
OUT
≤
12.48V
MAX765M, -11.52V
≤
V
OUT
≤
12.48V
MAX766, -14.40V
≤
V
OUT
≤
-15.60V
MAX76_C
Reference Voltage
V
REF
MAX76_E
MAX76_M
REF Load Regulation
REF Line Regulation
Load Regulation (Note 2)
Line Regulation (Note 2)
Efficiency (Note 2)
SHDN Leakage Current
SHDN Input Voltage High
SHDN Input Voltage Low
V
IH
V
IL
0µA
≤
I
REF
≤
100µA
3V
≤
V+
≤
16V
0mA
≤
I
LOAD
≤
100mA
4V
≤
V+
≤
6V
10mA
≤
I
LOAD
≤
100mA, V
OUT
= -5V
V
IN
= 5V
V
OUT
= -15V
V+ = 16V, SHDN = 0V or V+
3V
≤
V+
≤
16V
3V
≤
V+
≤
16V
1.6
0.4
MAX76_C/E
MAX76_M
150
68
50
35
1.4700
1.4625
1.4550
260
120
120
105
1.5
1.5
1.5
4
4
40
0.008
0.12
80
82
±1
1.5300
1.5375
1.5450
10
15
100
mV
µV/V
%/mA
%/V
%
µA
V
V
V
mA
-10
CONDITIONS
MIN
3.0
3.5
90
2
1
5
10
±50
±70
±90
nA
mV
120
µA
TYP
MAX
16.0
UNITS
V
2
_______________________________________________________________________________________
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
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.)
PARAMETER
LX Leakage Current
LX On-Resistance
Peak Current at LX
Maximum Switch On-Time
Minimum Switch Off-Time
I
PEAK
t
ON
t
OFF
SYMBOL
CONDITIONS
MAX76_C
MIN
TYP
MAX
±5
±10
±30
1.4
0.5
12
1.8
0.75
16
2.3
20
2.8
2.5
Ω
A
µs
µs
µA
UNITS
MAX764/MAX765/MAX766
I
LX
I
+ (V+)
≤
20V
I
V
OUT
I
+ (V+)
≥
10V
I
V
OUT
I
+ (V+)
≥
10V
MAX76_E
MAX76_M
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.
__________________________________________Typical Operating Characteristics
(V+ = 5V, V
OUT
= -5V, T
A
= +25°C, unless otherwise noted.)
MAX764
EFFICIENCY vs. LOAD CURRENT
MAX764-01
MAX765
EFFICIENCY vs. LOAD CURRENT
MAX764-02
MAX766
EFFICIENCY vs. LOAD CURRENT
90
80
MAX764-03
100
90
80
EFFICIENCY (%)
V+ = 5V
100
90
80
EFFICIENCY (%)
V+ = 5V
V+ = 8V
100
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0.1
1
10
100
1000
LOAD CURRENT (mA)
CIRCUIT OF FIGURE 2
V
OUT
= -5V ±4%
V+ = 15V
V+ = 10V
70
60
50
40
30
20
10
0
0.1
1
10
70
60
50
40
30
20
V+ = 5V
CIRCUIT OF FIGURE 2
V
OUT
= -12V ±4%
100
1000
10
0
0.1
1
CIRCUIT OF FIGURE 2
V
OUT
= -15V ±4%
10
100
1000
LOAD CURRENT (mA)
LOAD CURRENT (mA)
_______________________________________________________________________________________
3
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
MAX764/MAX765/MAX766
____________________________Typical Operating Characteristics (continued)
(V+ = 5V, V
OUT
= -5V, T
A
= +25°C, unless otherwise noted.)
MAXIMUM OUTPUT CURRENT
vs. SUPPLY VOLTAGE
MAX764 -04
NO-LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX764 -05
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
NO-LOAD SUPPLY CURRENT (µA)
MAX764 -06
600
MAXIMUM OUTPUT CURRENT (mA)
CIRCUIT OF FIGURE 2
500
400
300
200
V
OUT
= -12V
100
V
OUT
= -15V
0
V
OUT
= -5V
100
NO-LOAD SUPPLY CURRENT (µA)
95
90
85
80
75
70
65
60
110
105
100
95
90
85
80
75
70
65
60
55
50
V+ = 15V
V+ = 5V
3 4 5 6 7 8 9 10 11 12 13 14 15 16
SUPPLY VOLTAGE (V)
3 4 5 6 7 8 9 10 11 12 13 14 15 16
SUPPLY VOLTAGE (V)
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX764 -07
MAXIMUM SWITCH ON-TIME
vs. TEMPERATURE
MINIMUM SWITCH OFF-TIME (µs)
MAXIMUM SWITCH ON-TIME (µs)
16.8
16.6
16.4
16.2
16.0
15.8
15.6
15.4
15.2
15.0
V+ = 5V
V+ = 15V
MAX764 -08
MINIMUM SWITCH OFF-TIME
vs. TEMPERATURE
2.55
2.50
2.45
2.40
2.35
2.30
2.25
2.20
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
V+ = 5V
V+ = 15V
MAX764 -09
4.0
3.5
SHUTDOWN CURRENT (µA)
3.0
2.5
V+ = 15V
2.0
1.5
V+ = 8V
1.0
0.5
0
V+ = 4V
-60 -40 -20
17.0
2.60
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
SWITCH ON/OFF-TIME RATIO
vs. TEMPERATURE
MAX764 -10
START-UP SUPPLY VOLTAGE
vs. OUTPUT CURRENT
CIRCUIT OF FIGURE 2
START-UP SUPPLY VOLTAGE (V)
7
6
5
4
3
2
1
0
1
0
50
100
150
200
250
300
MAX764 -11
LX LEAKAGE CURRENT
vs. TEMPERATURE
I
V
OUT
I
+ (V+) = 20V
LX LEAKAGE CURRENT (nA)
1000
MAX764-12
7.2
SWITCH ON/OFF-TIME RATIO (µs/µs)
7.1
7.0
6.9
6.8
6.7
6.6
6.5
6.4
6.3
6.2
-60 -40 -20
V+ = 5V
8
10,000
100
10
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
20 30 40 50 60 70 80 90 100 110 120 130
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
4
_______________________________________________________________________________________
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
DC-DC Inverters
____________________________Typical Operating Characteristics (continued)
(V+ = 5V, V
OUT
= -5V, T
A
= +25°C, unless otherwise noted.)
MAX764/MAX765/MAX766
LX ON-RESISTANCE
vs. TEMPERATURE
MAX764 -13
PEAK CURRENT AT LX
vs. TEMPERATURE
MAX764 -14
REFERENCE OUTPUT RESISTANCE
vs. TEMPERATURE
REFERENCE OUTPUT RESISTANCE (Ω)
MAX764 -15
2.2
2.0
LX ON-RESISTANCE (Ω)
0.95
0.90
CURRENT AT LX (A)
250
I
V
OUT
I
+ (V+) = 10V
1.8
1.6
200
I
V
OUT
I
+ (V+) = 20V
0.85
I
REF
= 10µA
I
V
OUT
I
+ (V+) = 15V
1.4
1.2
1.0
I
V
OUT
I
+ (V+) = 15V
0.80
0.75
0.70
150
I
REF
= 50µA
100
50
I
REF
= 100µA
0
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
I
V
OUT
I
+ (V+) = 20V
0.8
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
0.65
I
V
OUT
I
+ (V+) = 10V
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
REFERENCE OUTPUT
vs. TEMPERATURE
MAX764 -16
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX764-17
1.506
1.504
REFERENCE OUTPUT (V)
1.502
1.500
1.498
1.496
1.494
1.492
-60 -40 -20
1000
I
LOAD
= 100mA
SUPPLY CURRENT (mA)
100
10
1
I
LOAD
= 0mA
0.1
CIRCUIT OF FIGURE 2
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
0.01
0
2
4
6
8
10
12
14
16
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
5
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