19-0201; Rev 0; 11/93
Kit
tion e
lua
l
Eva vailab
A
12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Converters
____________________________Features
o
High Efficiency for a Wide Range of Load Currents
o
12V/150mA Flash Memory Programming Supply
o
110µA Max Supply Current
o
5µA Max Shutdown Supply Current
o
2V to 16.5V Input Voltage Range
o
12V (MAX761), 15V (MAX762) or Adjustable Output
o
Current-Limited PFM Control Scheme
o
300kHz Switching Frequency
o
Internal, 1A, N-Channel Power FET
o
LBI/LBO Low-Battery Comparator
_______________General Description
The MAX761/MAX762 step-up switching regulators
provide high efficiency over a wide range of load currents,
delivering up to 150mA. A unique, current-limited
pulse-frequency-modulated (PFM) control scheme gives
the devices the benefits of pulse-width-modulated (PWM)
converters (high efficiency with heavy loads), while using
less than 110µA of supply current (vs. 2mA to 10mA for
PWM converters). The result is high efficiency over a wide
range of loads.
The MAX761/MAX762 input voltage range is 2V to 16.5V.
Output voltages are preset to 12V (MAX761) and 15V
(MAX762), or they can be set with two external resistors.
With a 5V input, the MAX761 guarantees a 12V, 150mA
output. Its high efficiency, low supply current, fast start-up
time, SHDN controlling capability, and small size make the
MAX761 ideal for powering flash memory.
The MAX761/MAX762 have an internal 1A power MOS-
FET, making them ideal for minimum-component, low- and
medium-power applications. These devices use tiny exter-
nal components, and their high switching frequencies (up
to 300kHz) allow for small surface-mount magnetics.
For increased output drive capability or higher output volt-
ages, use the MAX770–MAX773, which are similar in
design to the MAX761/MAX762, but drive external power
MOSFETs. For stepping up to 5V, see the MAX756/
MAX757 and MAX856-MAX859 data sheets.
MAX761/MAX762
______________Ordering Information
PART
MAX761CPA
MAX761CSA
MAX761C/D
MAX761EPA
MAX761ESA
MAX761MJA
MAX762CPA
MAX762CSA
MAX762C/D
MAX762EPA
MAX762ESA
MAX762MJA
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
Flash Memory Programming
PCMCIA Cards
Battery-Powered Applications
High-Efficiency DC-DC Converters
* Contact factory for dice specifications.
** Contact factory for availability and processing to MIL-STD-883.
__________Typical Operating Circuit
INPUT
4.75V
TO 12V
__________________Pin Configuration
TOP VIEW
33µF
18µH
LX
OUTPUT
12V
150mA
33µF
LBO
LBI
FB
1
2
3
8
V+
LX
GND
REF
ON/OFF
MAX761
SHDN
LBI
V+
MAX761
MAX762
7
6
5
LOW-BATTERY
DETECTOR INPUT
LBO
REF
FB
GND
LOW-BATTERY
DETECTOR OUTPUT
SHDN
4
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Converters
MAX761/MAX762
ABSOLUTE MAXIMUM RATINGS
Supply Voltage V+ to GND .......................................-0.3V to 17V
REF, LBO, LBI, SHDN, FB ............................-0.3V to (V+ + 0.3V)
LX..............................................................................-0.3V to 17V
LX Peak Current ....................................................................1.5A
LBO Current ..........................................................................5mA
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
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,
typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
Supply Voltage
Minimum Operating Voltage
Minimum Start-Up Voltage
SYMBOL
V+
CONDITIONS
Figure 2, bootstrapped
Figure 3 or 5 with
external resistors.
Figure 2, bootstrapped
Figure 2, bootstrapped
V+ = 16.5V, normal operation, SHDN = 0V,
non-bootstrapped
Supply Current
Figure 2, MAX761, V
IN
= 5V, SHDN = 0V,
normal operation
Shutdown Current
V+ = 10.0V, shutdown mode, SHDN = V+
Figure 2,
MAX761,
bootstrapped
V
OUT
Figure 2,
MAX762,
bootstrapped
I
PEAK
t
ON
t
OFF
Figure 2, 0mA
≤
I
LOAD
≤
200mA, bootstrapped
Figure 2, 4V
≤
V
IN
≤
6V, bootstrapped
Figure 2, bootstrapped, V
OUT
= 12V,
60mA
≤
I
LOAD
≤
120mA
MAX76_C
Reference Voltage
V
REF
MAX76_E
MAX76_M
1.4700
1.4625
1.4550
See Figure 4b
0mA
≤
I
LOAD
≤
75mA,
3V
≤
V+
≤
12V
0mA
≤
I
LOAD
≤
150mA,
4.75V
≤
V+
≤
12V
0mA
≤
I
LOAD
≤
50mA,
3V
≤
V+
≤
15V
0mA
≤
I
LOAD
≤
100mA,
4.75V
≤
V+
≤
15V
11.52
11.52
14.4
14.4
0.75
6
1.0
300
1
12.0
12.0
15.0
15.0
1.0
8
1.3
0.0042
0.08
86
1.50
1.50
1.50
1.5300
1.5375
1.5450
V
5
12.48
12.48
V
15.6
15.6
1.25
10
1.6
A
µs
µs
%/mA
%/V
%
µA
MAX76_C/E
MAX76_M
MIN
2
3
3.1
1.7
1.7
88
2.0
110
µA
TYP
MAX
16.5
16.5
16.5
V
V
UNITS
V
Output Voltage
(Note 1)
Peak Current at LX
Maximum Switch-On Time
Minimum Switch-Off Time
Load Regulation
Line Regulation
Efficiency
2
_______________________________________________________________________________________
12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Converters
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, I
LOAD
= 0mA, C
REF
= 0.1µF, T
A
= T
MIN
to T
MAX
, typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
Reference Load Regulation
Reference Line Regulation
LX Leakage Current
SYMBOL
CONDITIONS
0µA
≤
I
LOAD
≤
100µA
3.0V
≤
V+
≤
16.5V
MAX76_C
V+ = 16.5V,
LX = 17V
MAX76_C
FB Leakage Current
I
FB
MAX76_E
MAX76_M
MAX76_C
Voltage Trip Point
LX On Resistance
SHDN Input High Voltage
SHDN Input Low Voltage
SHDN Leakage Current
LBI Threshold Voltage
LBI Hysteresis
LBI Leakage Current
LBO Leakage Current
LBO Voltage
LBI to LBO Delay
Note 1:
V
OL
V+ = 16.5V, V
LBI
= 1.5V
V+ = 16.5V, V
LBO
= 16.5V
V+ = 5.0V, I
SINK
= 1mA
Overdrive = 5mV
2.5
-20
-1
V
IH
V
IL
V
FB
MAX76_E
MAX76_M
V+ > 5.0V
2.0V
≤
V+
≤
16.5V
2.0V
≤
V+
≤
16.5V
V+ = 16.5V, SHDN = 0V or V+
MAX76_C
LBI falling
MAX76_E
MAX76_M
-1
1.4700
1.4625
1.4550
1.50
1.50
1.50
20
20
1
0.4
1.6
0.4
1
1.5300
1.5375
1.5450
mV
nA
µA
V
µs
V
MAX76_E
MAX76_M
-5
-10
-30
-20
-40
-60
1.4700
1.4625
1.4550
1.50
1.50
1.50
1.0
MAX76_C/E
MAX76_M
30
MIN
TYP
MAX
10
15
100
5
10
30
20
40
60
1.5300
1.5375
1.5450
2.2
Ω
V
V
µA
V
nA
µA
UNITS
mV
µV/V
MAX761/MAX762
See
Typical Operating Characteristics
for output current capability versus input voltage. Guarantees based on correlation
to switching on and off times, on-resistance, and peak-current ratings.
_______________________________________________________________________________________
3
12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Converters
MAX761/MAX762
__________________________________________Typical Operating Characteristics
(Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
EFFICIENCY vs. OUTPUT CURRENT
BOOTSTRAPPED
MAX761-01
EFFICIENCY vs. OUTPUT CURRENT
NON-BOOTSTRAPPED
MAX761-02
QUIESCENT CURRENT vs.
INPUT VOLTAGE
1.75
QUIESCENT CURRENT (mA)
1.50
1.25
1.00
0.75
0.50
0.25
0
NON-BOOTSTRAPPED
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
INPUT VOLTAGE (V)
BOOTSTRAPPED
(EXTERNAL RESISTORS)
V
OUT
= 12V
BOOTSTRAPPED
(INTERNAL RESISTORS)
MAX761-03
MAX761-09
MAX761-06
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0.1
1
10
100
VOUT = 12V
V
IN
= 2V
V
IN
= 10V
V
IN
= 5V
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0.1
1
10
VOUT = 12V
V
IN
= 10V
V
IN
= 5V
2.00
1000
100
1000
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
MAXIMUM OUTPUT CURRENT vs.
INPUT VOLTAGE
MAX761-04
REFERENCE OUTPUT RESISTANCE vs.
TEMPERATURE
REFERENCE OUTPUT RESISTANCE (Ω)
MAX761-05
REFERENCE vs.TEMPERATURE
COEFFICIENT
1.506
1.504
REFERENCE OUTPUT (V)
1.502
1.500
1.498
1.496
1.494
1.492
400
MAXIMUM OUTPUT CURRENT (mA)
350
BOOTSTRAPPED
300
250
200
150
NON-BOOTSTRAPPED
100
50
0
3.0
3.5
4.0
4.5
5.0
5.5
V
OUT
= 12V
250
200
10µA
150
100
50µA
100µA
50
0
6.0
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
NO-LOAD START-UP VOLTAGE
MAX761-07
MAX761
START-UP VOLTAGE vs. R
LOAD
2.1
START-UP VOLTAGE (V)
2.0
1.9
1.8
1.7
1.6
1.5
0.6
1.4
1.3
0.4
0.1
1
10
R
LOAD
(kΩ)
100
1000
V
OUT
= 12V
BOOTSTRAPPED
INTERNAL RESISTORS
MAX761-08
LX ON-RESISTANCE vs.
TEMPERATURE
1.6
1.4
LX ON-RESISTANCE (Ω)
V+ = 5V
1.2
1.0
0.8
3.5
V
OUT
= 12V
NO-LOAD START-UP VOLTAGE (V)
3.0
2.5
NON-BOOTSTRAPPED
(EXTERNAL RESISTORS)
2.0
1.5
1.0
0.5
-60 -40 -20
BOOTSTRAPPED
(INTERNAL RESISTORS)
BOOTSTRAPPED
(EXTERNAL RESISTORS)
2.2
V+ = 12V
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
4
_______________________________________________________________________________________
12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Converters
____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
MAX761/MAX762
LX LEAKAGE vs. TEMPERATURE
MAX761-10
PEAK CURRENT AT LX vs. TEMPERATURE
MAX761-11
SHUTDOWN CURRENT
vs. TEMPERATURE
3.5
3.0
I
CC
(µA)
2.5
2.0
1.5
V+ = 8V
1.0
0.5
0
V+ = 4V
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
V+ = 15V
MAX761-12
1000
V+ = 15V
100
LX LEAKAGE (nA)
1.5
1.4
1.3
1.2
V+ = 12V
4.0
10
I
PEAK
(A)
1.1
1.0
0.9
0.8
V+ = 5V
1
0.1
V
LX
= 16.5V
0.7
0.6
0.01
20
40
60
80
100 120
TEMPERATURE (°C)
140
0.5
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
SWITCH-ON TIME vs. TEMPERATURE
MAX761-13
SWITCH-OFF TIME vs. TEMPERATURE
MAX761-14
POWER-SUPPLY CURRENT
vs. TEMPERATURE
MAX761-15
8.5
2.0
100
V+ = 16.5V
V+ = 3V
V+ = 5V
toff (µs)
ton (µs)
V+ = 5V
I
CC
(µA)
-60
0
60
120
8.0
1.5
90
7.5
-60
0
60
120
TEMPERATURE (°C)
1.0
TEMPERATURE (°C)
80
-60
0
60
120
TEMPERATURE (°C)
SWITCH-ON/SWITCH-OFF TIME RATIO
vs.TEMPERATURE
MAX761-16
SHDN RESPONSE TIME
12V
7
ton/toff RATIO (µs/µs)
V+ = 5V
6
5V
4V
0V
5
-60
0
60
120
I
LOAD
= 100mA, V
IN
= 5V
A: V
OUT
, 2V/div
B: SHDN (0V to 4V)
TEMPERATURE (°C)
2ms/div
_______________________________________________________________________________________
5
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