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Part Number MAX773

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_______________General Description
The MAX770­MAX773 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 MAX770­MAX773 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.
________________________Applications
Palmtops/Handy-Terminals
High-Efficiency DC-DC Converters
Battery-Powered Applications
Positive LCD-Bias Generators
Portable Communicators
Flash Memory Programmers
____________________________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
______________Ordering Information
Ordering Information continued at end of data sheet.
*Contact factory for dice specifications.
**Contact factory for availability and processing to MIL-STD-883B.
MAX770­MAX773
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
________________________________________________________________
Maxim Integrated Products
1
1
2
3
4
8
7
6
5
CS
GND
AGND
REF
SHDN
FB
V+
EXT
MAX770
MAX771
MAX772
DIP/SO
_________________Pin Configurations
FB AGND GND
V+
CS
EXT
N
REF
SHDN
ON/OFF
OUTPUT
12V
INPUT
2V TO VOUT
MAX771
__________Typical Operating Circuit
PART
TEMP. RANGE
PIN-PACKAGE
MAX770
CPA
0°C to +70°C
Plastic DIP
MAX770CSA
0°C to +70°C
8 SO
MAX770C/D
0°C to +70°C
Dice*
MAX770EPA
-40°C to +85°C
8 Plastic DIP
MAX770ESA
-40°C to +85°C
8 SO
MAX770MJA
-55°C to +125°C
8 CERDIP**
TOP VIEW
Pin Configurations continued at end of data sheet.
19-0202; Rev 2; 11/96
EVALUATION KIT MANUAL
FOLLOWS DATA SHEET
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.
MAX770­MAX773
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
2
_______________________________________________________________________________________
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
MIN
TYP
MAX
UNITS
Supply Current
85
110
µ
A
Standby Current
2
5
µ
A
4
Output Voltage (Note 1)
V+ = 2.0V to 5.0V, over full load range
4.80
5.0
5.20
V
V+ = 2.0V to 12.0V, over full load range
11.52
12.0
12.48
V+ = 2.0V to 15.0V, over full load range
14.40
15.0
15.60
Figure 2a, V+ = 2.7V to 4.5V,
I
LOAD
= 700mA, V
OUT
= 5V
5
mV/V
Figure 2a, V+ = 3V, I
LOAD
= 30mA to 1A,
V
OUT
= 5V
20
mV/A
Maximum Switch On-Time
t
ON
(max)
12
16
20
µ
s
Minimum Switch Off-Time
t
OFF
(min)
1.8
2.3
2.8
µ
s
Efficiency
87
%
Reference Voltage
V
REF
I
REF =
0
µ
A
MAX77_C
1.4700
1.5
1.5300
V
MAX77_E
1.4625
1.5
1.5375
MAX77_M
1.4550
1.5
1.5450
Output Voltage Line Regulation
(Note 2)
Output Voltage Load Regulation
(Note 2)
V+ = 4V, I
LOAD
= 500mA, V
OUT
= 5V
V+ = 10.0V, SHDN
1.6V (shutdown)
V+ = 16.5V, SHDN
1.6V (shutdown)
V+ = 16.5V, SHDN = 0V (normal operation)
Minimum Start-Up Voltage
MAX770/MAX771/MAX772
1.8
2.0
V
MAX770­772 (internal feedback resistors)
2.0
16.5
MAX770­772C/E (external resistors)
3.0
16.5
MAX770­772MJA (external resistors)
3.1
16.5
MAX773C/E
3.0
16.5
MAX773MJD
3.1
16.5
Input Voltage Range
V
MAX770­MAX773
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
_______________________________________________________________________________________
3
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
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
REF Load Regulation
0
µ
A
I
REF
100
µ
A
MAX77_C/E
4
10
mV
MAX77_M
4
15
REF Line Regulation
3V
V+
16.5V
40
100
µ
V/V
FB Trip-Point Voltage
V
FB
MAX77_C
1.4700
1.50
1.5300
V
MAX77_E
1.4625
1.50
1.5375
MAX77_M
1.4550
1.50
1.5450
FB Input Current
I
FB
MAX77_C
±20
nA
MAX77_E
±40
MAX77_M
±60
SHDN Input High Voltage
V
IH
V+ = 2.0V to 16.5V
1.6
V
SHDN Input Low Voltage
V
IL
MAX77_C/E, V+ = 2.0V to 16.5V
0.4
V
SHDN Input Current
±1
µ
A
LBI Input Current
MAX773, V+ = 16.5V, LBI = 1.5V
±20
nA
LBI Hysteresis
MAX773
20
LBI Threshold Voltage
MAX773, LBI falling
MAX77_C
1.4700
1.50
1.5300
V
MAX77_E
1.4625
1.50
1.5375
MAX77_M
1.4550
1.50
1.5450
LBO Leakage Current
MAX773, V+ = 16.5V, V
LBO
= 16.5V
0.01
1.00
µ
A
LBO Output Voltage Low
V
OL
MAX773, V+ = 5V, LBO sinking 1mA
0.1
0.4
V
V+ = 16.5V, SHDN = 0V or V+
mV
Current-Limit Trip Level
V
CS
V+ = 5V to 16.5V
170
200
230
mV
V
SHUNT
MAX773, I
SHUNT
= 1mA to 20mA,
SGND = 0V, C
SHUNT
= 0.1
µ
F
5.5
6.3
V
CS Input Current
0.01
±1
µ
A
EXT Rise Time
V+ = 5V, 1nF from EXT to ground (Note 3)
55
ns
EXT Fall Time
V+ = 5V, 1nF from EXT to ground (Note 3)
55
ns
Supply Voltage in
Shunt Mode
Note 1:
Output voltage guaranteed using preset voltages. See Figures 7a­7d 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.
LBI Delay
5mV overdrive
2.5
µs
MAX77_M, V+ = 2.0V to 16.5V
0.2
0
1
2
3
4
-75
-50
-25
0
25
50
75
100 125
SUPPLY CURRENT vs. TEMPERATURE
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
V
OUT
= 12V, V
IN
= 5V
CIRCUIT OF FIGURE 2b
BOOTSTRAPPED MODE
ENTIRE
CIRCUIT
SCHOTTKY DIODE
LEAKAGE EXCLUDED
MAX770­3-07
0
0.2
0.4
0.6
0.8
2
4
6
8
10
12
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
V
OUT
= 12V
NON-BOOTSTRAPPED
CIRCUIT OF FIGURE 2c
BOOTSTRAPPED
CIRCUIT OF
FIGURE 2b
MAX770­3-08
0
100
150
200
250
50
2
4
6
8
10
12
EXT RISE/FALL TIME vs. SUPPLY VOLTAGE
V+ (V)
EXT RISE/FALL TIME (ns)
C
EXT
= 2200pF
C
EXT
= 1000pF
C
EXT
= 446pF
C
EXT
= 100pF
MAX770­3-09
100
50
0.001
0.01
0.1
1
MAX772
EFFICIENCY vs. OUTPUT CURRENT
(BOOTSTRAPPED)
60
OUTPUT CURRENT (A)
EFFICIENCY (%)
70
80
90
V
OUT
= 15V, CIRCUIT OF FIGURE 2b
MAX772 SUBSTITUTED FOR MAX771
V
IN
= 12V
V
IN
= 9V
V
IN
= 6V
V
IN
= 5V
V
IN
= 3V
MAX770­3-03
50
60
70
80
90
100
0.001
0.01
1
MAX771
EFFICIENCY vs. OUTPUT CURRENT
(BOOTSTRAPPED)
OUTPUT CURRENT (A)
EFFICIENCY (%)
0.1
V
IN
= 6V
V
IN
= 5V
V
IN
= 3V
V
IN
= 9V
V
OUT
= 12V
CIRCUIT OF
FIGURE 2b
MAX770­3-02
100
50
0.001
0.01
0.1
1
MAX770
EFFICIENCY vs. OUTPUT CURRENT
(BOOTSTRAPPED)
60
OUTPUT CURRENT (A)
EFFICIENCY (%)
70
80
90
V
IN
= 3V
V
IN
= 3.5V
V
OUT
= 5V
CIRCUIT OF
FIGURE 2a
V
IN
= 4V
MAX770­3-01
MAX770­MAX773
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
4
_______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
70
80
90
100
0.001
0.01
0.1
10
1
MAX771
EFFICIENCY vs. OUTPUT CURRENT
(NON-BOOTSTRAPPED)
OUTPUT CURRENT (A)
EFFICIENCY (
%
)
V
IN
= 9V
V
IN
= 6V
V
IN
= 5V
V
OUT
= 12V
CIRCUIT OF
FIGURE 2c
MAX770­3-04
0
100
200
300
400
500
600
700
1.0
MAX770
LOAD CURRENT vs.
MINIMUM START-UP INPUT VOLTAGE
MINIMUM START-UP INPUT VOLTAGE (V)
LOAD CURRENT (mA)
3.0
1.5
2.5
3.5
2.0
ABOVE 3.4V,
THE CIRCUIT
STARTS UP
UNDER
MAXIMUM
LOAD
CONDITIONS
V
OUT
= 5V
CIRCUIT OF
FIGURE 2a
MAX770­3-05
0
100
200
300
400
500
2.0
MAX771
LOAD CURRENT vs.
MINIMUM START-UP INPUT VOLTAGE
MINIMUM START-UP INPUT VOLTAGE (V)
LOAD CURRENT (mA)
4.0
2.5
3.5
3.0
ABOVE 3.5V
THE CIRCUIT
STARTS UP
UNDER
MAXIMUM
LOAD
CONDITIONS
V
OUT
= 12V
CIRCUIT OF
FIGURE 2b
MAX770­3-06
MAX770­MAX773
5V/12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Controllers
_______________________________________________________________________________________
5
250
0
-60
-20
60
140
REFERENCE OUTPUT RESISTANCE vs.
TEMPERATURE
50
MAX770­3-10
TEMPERATURE (
°
C)
REFERENCE OUTPUT RESISTANCE (
)
20
100
150
-40
0
80
40
120
100
200
100µA
50µA
10µA
1.502
-60
-20
60
140
REFERENCE vs. TEMPERATURE
MAX770­3-11
TEMPERATURE (
°
C)
REFERENCE (V)
20
100
-40
0
80
40
120
1.500
1.498
1.496
1.494
1.492
1.504
1.506
4.0
-60
-20
60
140
SHUTDOWN CURRENT vs. TEMPERATURE
MAX770­3-12
TEMPERATURE (
°
C)
I
CC
(µA)
20
100
-40
0
80
40
120
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
V+ = 15V
V+ = 4V
V+ = 8V
15.5
16.0
16.5
-60 -30
0
30
60
90
120
150
MAXIMUM SWITCH ON-TIME vs.
TEMPERATURE
TEMPERATURE (°C)
t ON(MAX) (µs)
MAX770­3-13
2.20
2.25
2.30
-60 -30
0
30
60
90
120
150
MINIMUM SWITCH OFF-TIME vs.
TEMPERATURE
TEMPERATURE (°C)
t OFF(MIN) (µs)
MAX770­3-14
6.0
7.0
8.0
-60 -30
0
30
60
90
120
150
MAXIMUM SWITCH ON-TIME/
MINIMUM SWITCH OFF-TIME RATIO
vs. TEMPERATURE
TEMPERATURE (°C)
t ON(MAX)/
t OFF(MIN) RATIO
MAX770­3-15
7.5
6.5
____________________________Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)