19-0202; Rev 2; 11/96
L
MANUA
ION KIT HEET
AT
EVALU
TA S
WS DA
FOLLO
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
____________________________Features
o
90% Efficiency for 10mA to 1A Load Currents
o
Up to 15W Output Power
o
110µA Max Supply Current
o
5µA Max Shutdown Current
o
2V to 16.5V Input Range
(MAX770/MAX771/MAX772)
o
Internal Shunt Regulator for High Input Voltages
(MAX773)
o
Preset or Adjustable Output Voltages
MAX770: 5V or Adjustable
MAX771: 12V or Adjustable
MAX772: 15V or Adjustable
MAX773: 5V, 12V, 15V, or Adjustable
o
Current-Limited PFM Control Scheme
o
300kHz Switching Frequency
_______________General Description
The MAX770–MAX773 step-up switching controllers pro-
vide 90% efficiency over a 10mA to 1A load. A
unique current-limited pulse-frequency-modulation (PFM)
control scheme gives these devices the benefits of
pulse-width-modulation (PWM) converters (high efficiency
at heavy loads), while using less than 110µA of supply
current (vs. 2mA to 10mA for PWM converters).
These ICs use tiny external components. Their high
switching frequencies (up to 300kHz) allow surface-
mount magnetics of 5mm height and 9mm diameter.
The MAX770/MAX771/MAX772 accept input voltages
from 2V to 16.5V. Output voltages are preset at 5V,
(MAX770), 12V (MAX771), and 15V (MAX772); they can
also be adjusted using two resistors.
The MAX773 accepts inputs from 3V to 16.5V. For a wider
input range, it features an internal shunt regulator that
allows unlimited higher input voltages. The MAX773’s out-
put can be set to 5V, 12V, or 15V, or it can be adjusted
with two resistors.
The MAX770–MAX773 drive external N-channel MOSFET
switches, allowing them to power loads up to 15W. If less
power is required, use the MAX756/MAX757 or
MAX761/MAX762 step-up switching regulators with on-
board MOSFETs.
MAX770–MAX773
______________Ordering Information
PART
MAX770CPA
MAX770CSA
MAX770C/D
MAX770EPA
MAX770ESA
MAX770MJA
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
PIN-PACKAGE
Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP**
________________________Applications
Palmtops/Handy-Terminals
High-Efficiency DC-DC Converters
Battery-Powered Applications
Positive LCD-Bias Generators
Portable Communicators
Flash Memory Programmers
Ordering Information continued at end of data sheet.
*Contact factory for dice specifications.
**Contact factory for availability and processing to MIL-STD-883B.
_________________Pin Configurations
__________Typical Operating Circuit
INPUT
2V TO VOUT
OUTPUT
12V
EXT
V+
1
2
8
CS
GND
AGND
REF
7
6
5
TOP VIEW
MAX771
ON/OFF
SHDN
EXT
CS
N
FB
3
SHDN
4
MAX770
MAX771
MAX772
DIP/SO
REF
FB AGND GND
V+
Pin Configurations continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
MAX770–MAX773
ABSOLUTE MAXIMUM RATINGS
Supply Voltages
V+ to GND.............................................................-0.3V to 17V
V+ to SGND.............................................................-0.3V to 7V
SGND........................................................-0.3V to (V+ + 0.3V)
EXT, CS, REF, LBO, LBI, SHDN, FB.............-0.3V to (V+ + 0.3V)
EXTH, EXTL ..................................................-0.3V to (V+ + 0.3V)
V5, V12, V15 .............................................................-0.3V to 17V
GND to AGND .........................................................0.1V to -0.1V
I
SGND
..................................................................................50mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C)....727mW
8-Pin 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
14-Pin SO (derate 8.33mW/°C above +70°C) ..............667mW
14-Pin CERDIP (derate 9.09mW/°C above +70°C) ......727mW
Operating Temperature Ranges
MAX77_C_ _ ........................................................0°C to +70°C
MAX77_E_ _......................................................-40°C to +85°C
MAX77_MJ_ ...................................................-55°C to +125°C
Junction Temperatures
MAX77_C_ _/E_ _ ..........................................................+150°C
MAX77_MJ_..................................................................+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, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MAX770–772 (internal feedback resistors)
MAX770–772C/E (external resistors)
Input Voltage Range
MAX770–772MJA (external resistors)
MAX773C/E
MAX773MJD
Minimum Start-Up Voltage
Supply Current
Standby Current
MAX770/MAX771/MAX772
V+ = 16.5V, SHDN = 0V (normal operation)
V+ = 10.0V, SHDN
≥
1.6V (shutdown)
V+ = 16.5V, SHDN
≥
1.6V (shutdown)
V+ = 2.0V to 5.0V, over full load range
Output Voltage (Note 1)
V+ = 2.0V to 12.0V, over full load range
V+ = 2.0V to 15.0V, over full load range
Output Voltage Line Regulation
(Note 2)
Output Voltage Load Regulation
(Note 2)
Maximum Switch On-Time
Minimum Switch Off-Time
Efficiency
Reference Voltage
V
REF
t
ON
(max)
t
OFF
(min)
V+ = 4V, I
LOAD
= 500mA, V
OUT
= 5V
MAX77_C
I
REF =
0µA
MAX77_E
MAX77_M
1.4700
1.4625
1.4550
Figure 2a, V+ = 2.7V to 4.5V,
I
LOAD
= 700mA, V
OUT
= 5V
Figure 2a, V+ = 3V, I
LOAD
= 30mA to 1A,
V
OUT
= 5V
12
1.8
4.80
11.52
14.40
MIN
2.0
3.0
3.1
3.0
3.1
1.8
85
2
4
5.0
12.0
15.0
5
5.20
12.48
15.60
mV/V
V
TYP
MAX
16.5
16.5
16.5
16.5
16.5
2.0
110
5
V
µA
µA
V
UNITS
20
16
2.3
87
1.5
1.5
1.5
1.5300
1.5375
1.5450
20
2.8
mV/A
µs
µs
%
V
2
_______________________________________________________________________________________
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, I
LOAD
= 0mA, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETERS
REF Load Regulation
REF Line Regulation
SYMBOL
CONDITIONS
0µA
≤
I
REF
≤
100µA
3V
≤
V+
≤
16.5V
MAX77_C
FB Trip-Point Voltage
V
FB
MAX77_E
MAX77_M
MAX77_C
FB Input Current
I
FB
MAX77_E
MAX77_M
SHDN Input High Voltage
SHDN Input Low Voltage
SHDN Input Current
LBI Input Current
LBI Hysteresis
LBI Delay
V
IH
V
IL
V+ = 2.0V to 16.5V
MAX77_C/E, V+ = 2.0V to 16.5V
MAX77_M, V+ = 2.0V to 16.5V
V+ = 16.5V, SHDN = 0V or V+
MAX773, V+ = 16.5V, LBI = 1.5V
MAX773
5mV overdrive
MAX77_C
LBI Threshold Voltage
MAX773, LBI falling
MAX77_E
MAX77_M
LBO Leakage Current
LBO Output Voltage Low
Current-Limit Trip Level
CS Input Current
EXT Rise Time
EXT Fall Time
Supply Voltage in
Shunt Mode
V
SHUNT
V+ = 5V, 1nF from EXT to ground (Note 3)
V+ = 5V, 1nF from EXT to ground (Note 3)
MAX773, I
SHUNT
= 1mA to 20mA,
SGND = 0V, C
SHUNT
= 0.1µF
5.5
V
OL
V
CS
MAX773, V+ = 16.5V, V
LBO
= 16.5V
MAX773, V+ = 5V, LBO sinking 1mA
V+ = 5V to 16.5V
170
1.4700
1.4625
1.4550
20
2.5
1.50
1.50
1.50
0.01
0.1
200
0.01
55
55
6.3
1.5300
1.5375
1.5450
1.00
0.4
230
±1
µA
V
mV
µA
ns
ns
V
V
1.6
0.4
0.2
±1
±20
1.4700
1.4625
1.4550
MAX77_C/E
MAX77_M
MIN
TYP
4
4
40
1.50
1.50
1.50
MAX
10
15
100
1.5300
1.5375
1.5450
±20
±40
±60
V
V
µA
nA
mV
µs
nA
V
UNITS
mV
µV/V
MAX770–MAX773
3
Note 1:
Output voltage guaranteed using preset voltages. See Figures 7a–7d for output current capability versus input voltage.
Note 2:
Output voltage line and load regulation depend on external circuit components.
Note 3:
For the MAX773, EXT is EXTH and EXTL shorted together.
_______________________________________________________________________________________
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
MAX770–MAX773
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
MAX770
EFFICIENCY vs. OUTPUT CURRENT
(BOOTSTRAPPED)
MAX770–3-01
MAX771
EFFICIENCY vs. OUTPUT CURRENT
(BOOTSTRAPPED)
MAX770–3-02
MAX772
EFFICIENCY vs. OUTPUT CURRENT
(BOOTSTRAPPED)
V
OUT
= 15V, CIRCUIT OF FIGURE 2b
MAX772 SUBSTITUTED FOR MAX771
90
EFFICIENCY (%)
MAX770–3-03
100
V
IN
= 4V
100
V
IN
= 9V
90
EFFICIENCY (%)
V
IN
= 6V
100
90
EFFICIENCY (%)
80
80
80
70
V
IN
= 3V
60
V
IN
= 3.5V
V
OUT
= 5V
CIRCUIT OF
FIGURE 2a
0.001
0.01
0.1
1
70
V
IN
= 5V
60
50
0.001
V
IN
= 3V
V
OUT
= 12V
CIRCUIT OF
FIGURE 2b
0.1
1
70
60
V
IN
= 12V
V
IN
= 9V
V
IN
= 6V
V
IN
= 5V
V
IN
= 3V
0.001
0.01
0.1
1
50
OUTPUT CURRENT (A)
50
0.01
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
MAX771
EFFICIENCY vs. OUTPUT CURRENT
(NON-BOOTSTRAPPED)
MAX770–3-04
MAX770
LOAD CURRENT vs.
MINIMUM START-UP INPUT VOLTAGE
MAX770–3-05
MAX771
LOAD CURRENT vs.
MINIMUM START-UP INPUT VOLTAGE
V
OUT
= 12V
CIRCUIT OF
FIGURE 2b
MAX770–3-06
100
700
600
LOAD CURRENT (mA)
500
400
300
200
100
ABOVE 3.4V,
THE CIRCUIT
STARTS UP
UNDER
MAXIMUM
LOAD
CONDITIONS
1.0
1.5
2.0
2.5
3.0
V
OUT
= 5V
CIRCUIT OF
FIGURE 2a
500
V
OUT
= 12V
CIRCUIT OF
FIGURE 2c
V
IN
= 9V
400
LOAD CURRENT (mA)
EFFICIENCY (%)
90
V
IN
= 6V
V
IN
= 5V
80
300
200
100
0
3.5
2.0
2.5
3.0
70
0.001
0
0.01
0.1
1
10
OUTPUT CURRENT (A)
ABOVE 3.5V
THE CIRCUIT
STARTS UP
UNDER
MAXIMUM
LOAD
CONDITIONS
3.5
4.0
MINIMUM START-UP INPUT VOLTAGE (V)
MINIMUM START-UP INPUT VOLTAGE (V)
SUPPLY CURRENT vs. TEMPERATURE
V
OUT
= 12V, V
IN
= 5V
CIRCUIT OF FIGURE 2b
BOOTSTRAPPED MODE
ENTIRE
CIRCUIT
2
MAX770–3-07
SUPPLY CURRENT vs. SUPPLY VOLTAGE
V
OUT
= 12V
SUPPLY CURRENT (mA)
0.6
BOOTSTRAPPED
CIRCUIT OF
FIGURE 2b
MAX770–3-08
EXT RISE/FALL TIME vs. SUPPLY VOLTAGE
MAX770–3-09
4
0.8
250
200
EXT RISE/FALL TIME (ns)
SUPPLY CURRENT (mA)
3
C
EXT
= 2200pF
C
EXT
= 1000pF
C
EXT
= 446pF
C
EXT
= 100pF
150
0.4
100
1
SCHOTTKY DIODE
LEAKAGE EXCLUDED
0.2
NON-BOOTSTRAPPED
CIRCUIT OF FIGURE 2c
50
0
0
-75 -50 -25
0
25
50
75 100 125
TEMPERATURE (°C)
0
2
4
6
8
10
12
2
4
6
8
V+ (V)
10
12
SUPPLY VOLTAGE (V)
4
_______________________________________________________________________________________
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
____________________________Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
REFERENCE OUTPUT RESISTANCE vs.
TEMPERATURE
REFERENCE OUTPUT RESISTANCE (Ω)
MAX770–3-10
MAX770–MAX773
REFERENCE vs. TEMPERATURE
MAX770–3-11
250
1.506
1.504
1.502
REFERENCE (V)
1.500
1.498
1.496
1.494
1.492
200
10µA
150
100
50µA
100µA
50
0
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
MAXIMUM SWITCH ON-TIME vs.
TEMPERATURE
MAX770–3-13
SHUTDOWN CURRENT vs. TEMPERATURE
3.5
3.0
MAX770–3-12
16.5
4.0
tON(MAX) (µs)
16.0
I
CC
(µA)
2.5
2.0
1.5
V+ = 8V
1.0
0.5
V+ = 4V
-60 -40 -20
0 20 40 60 80 100 120 140
TEMPERATURE (°C)
V+ = 15V
15.5
-60 -30
0
30
60
90
120 150
TEMPERATURE (°C)
0
MINIMUM SWITCH OFF-TIME vs.
TEMPERATURE
MAX770–3-14
MAXIMUM SWITCH ON-TIME/
MINIMUM SWITCH OFF-TIME RATIO
vs. TEMPERATURE
MAX770–3-15
2.30
8.0
tON(MAX)/tOFF(MIN) RATIO
7.5
tOFF(MIN) (µs)
2.25
7.0
6.5
2.20
-60 -30
0
30
60
90
120 150
TEMPERATURE (°C)
6.0
-60 -30
0
30
60
90
120 150
TEMPERATURE (°C)
_______________________________________________________________________________________
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