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MAX756ESA+

P1-P3P4-P6P7-P9
AVAILABLE
EVALUATION KIT AVAILABLE
Functional Diagrams
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and
ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
3.3V/5V/Adjustable-Output,
Step-Up DC-DC Converters
_______________General Description
The MAX756/MAX757 are CMOS step-up DC-DC switch-
ing regulators for small, low input voltage or battery-pow-
ered systems. The MAX756 accepts a positive input
voltage down to 0.7V and converts it to a higher pin-
selectable output voltage of 3.3V or 5V. The MAX757 is
an adjustable version that accepts an input voltage down
to 0.7V and generates a higher adjustable output voltage
in the range from 2.7V to 5.5V. Typical full-load efficiencies
for the MAX756/MAX757 are greater than 87%.
The MAX756/MAX757 provide three improvements over
previous devices. Physical size is reduced—the high
switching frequencies (up to 0.5MHz) made possible by
MOSFET power transistors allow for tiny (<5mm diameter)
surface-mount magnetics. Efficiency is improved to 87%
(10% better than with low-voltage regulators fabricated in
bipolar technology). Supply current is reduced to 60µA
by CMOS construction and a unique constant-off-time
pulse-frequency modulation control scheme.
________________________Applications
3.3V to 5V Step-Up Conversion
Palmtop Computers
Portable Data-Collection Equipment
Personal Data Communicators/Computers
Medical Instrumentation
2-Cell & 3-Cell Battery-Operated Equipment
Glucose Meters
____________________________Features
♦ Operates Down to 0.7V Input Supply Voltage
♦ 87% Efficiency at 200mA
♦ 60µA Quiescent Current
♦ 20µA Shutdown Mode with Active Reference and
LBI Detector
♦ 500kHz Maximum Switching Frequency
♦ ±1.5% Reference Tolerance Over Temperature
♦ Low-Battery Detector (LBI/LBO)
♦ 8-Pin DIP and SO Packages
______________Ordering Information
* Dice are tested at T
A
= +25°C only.
1
2
3
4
8
7
6
5
LX
GND
OUT
LBI
LBO
REF
3/5
SHDN
MAX756
DIP/SO
TOP VIEW
1
2
3
4
8
7
6
5
LX
GND
OUT
LBI
LBO
REF
FB
SHDN
MAX757
DIP/SO
_________________Pin Configurations
MAX756
SHDN
1
3/5
2
REF
3
LBI
5
LX
7
150μF
GND
OUT
6
INPUT
2V to V
OUT
1N5817
OUTPUT
5V at 200mA
or
3.3V at 300mA
100μF
LBO
4
8
0.1μF
22μH
LOW-BATTERY
DETECTOR OUTPUT
__________Typical Operating Circuit
PART TEMP. RANGE PIN-PACKAGE
MAX756CPA
0°C to +70°C 8 Plastic DIP
MAX756CSA 0°C to +70°C 8 SO
MAX756C/D 0°C to +70°C Dice*
MAX756EPA -40°C to +85°C 8 Plastic DIP
MAX756ESA -40°C to +85°C 8 SO
MAX757CPA
0°C to +70°C 8 Plastic DIP
MAX757CSA 0°C to +70°C 8 SO
MAX757C/D 0°C to +70°C Dice*
MAX757EPA -40°C to +85°C 8 Plastic DIP
MAX757ESA -40°C to +85°C 8 SO
3.3V/5V/Adjustable-Output,
Step-Up DC-DC Converters
19-0113; Rev. 2; 1/95
_______________General Description
The MAX756/MAX757 are CMOS step-up DC-DC switch-
ing regulators for small, low input voltage or battery-pow-
ered systems. The MAX756 accepts a positive input
voltage down to 0.7V and converts it to a higher pin-
selectable output voltage of 3.3V or 5V. The MAX757 is
an adjustable version that accepts an input voltage down
to 0.7V and generates a higher adjustable output voltage
in the range from 2.7V to 5.5V. Typical full-load efficiencies
for the MAX756/MAX757 are greater than 87%.
The MAX756/MAX757 provide three improvements over
previous devices. Physical size is reduced—the high
switching frequencies (up to 0.5MHz) made possible by
MOSFET power transistors allow for tiny (<5mm diameter)
surface-mount magnetics. Efficiency is improved to 87%
(10% better than with low-voltage regulators fabricated in
bipolar technology). Supply current is reduced to 60µA
by CMOS construction and a unique constant-off-time
pulse-frequency modulation control scheme.
________________________Applications
3.3V to 5V Step-Up Conversion
Palmtop Computers
Portable Data-Collection Equipment
Personal Data Communicators/Computers
Medical Instrumentation
2-Cell & 3-Cell Battery-Operated Equipment
Glucose Meters
____________________________Features
♦ Operates Down to 0.7V Input Supply Voltage
♦ 87% Efficiency at 200mA
♦ 60µA Quiescent Current
♦ 20µA Shutdown Mode with Active Reference and
LBI Detector
♦ 500kHz Maximum Switching Frequency
♦ ±1.5% Reference Tolerance Over Temperature
♦ Low-Battery Detector (LBI/LBO)
♦ 8-Pin DIP and SO Packages
______________Ordering Information
* Dice are tested at T
A
= +25°C only.
MAX756/MAX757
3.3V/5V/Adjustable-Output,
Step-Up DC-DC Converters
Supply Voltage (OUT to GND) ....................................-0.3V, +7V
Switch Voltage (LX to GND) ........................................-0.3V, +7V
Auxiliary Pin Voltages (SHDN
, LBI, LBO, REF,
3/5
, FB to GND) ........................................-0.3V, (V
OUT
+ 0.3V)
Reference Current (I
REF
) ....................................................2.5mA
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
Operating Temperature Ranges:
MAX75_C_ _ ........................................................0°C to +70°C
MAX75_E_ _......................................................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range............................... -65°to +160°C
Lead Temperature (soldering, 10sec) ........................... +300°C
ELECTRICAL CHARACTERISTICS
(Circuits of Figure 1 and Typical Operating Circuit, V
IN
= 2.5V, I
LOAD
= 0mA, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
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.
ABSOLUTE MAXIMUM RATINGS
Note 1: Supply current from the 3.3V output is measured with an ammeter between the 3.3V output and OUT pin. This current
correlates directly with actual battery supply current, but is reduced in value according to the step-up ratio and efficiency.
Note 2: Minimum value is production tested. Maximum value is guaranteed by design and is not production tested.
LBO Output Leakage Current
SHDN, 3/5, FB, LBI Input Current
V2.7 5.5
MAX757, I
LOAD
= 0mA (Note 2)
Output Voltage Range
V1.22 1.25 1.28MAX757FB Voltage
nA±100
LBI = 1.25V, FB = 1.25V, SHDN = 0V or 3V,
3/5 = 0V or 3V
V1.6SHDN, 3/5 Input Voltage High
V0.4SHDN, 3/5 Input Voltage Low
Shutdown Quiescent Current
(Note 1)
Battery Quiescent Current
Measured at V
IN
in Figure 1
V1.22 1.25 1.28With falling edgeLBI Input Threshold
mV25LBI Input Hysteresis
V0.4
I
SINK
= 2mA
LBO Output Voltage Low
µA1LBO = 5V
µA20 40
SHDN = 0V, LBI = 1.25V, 3/5 = 3V, V
OUT
= 3.47V,
FB = 1.3V (MAX757 only)
µA
Quiescent Supply Current in
3.3V Mode (Note 1)
MAX757, V
OUT
= 5V, 0mA < I
LOAD
< 200mA
MAX756, 3/5 = 0V, 0mA < I
LOAD
< 200mA
MAX756, 3/5 = 3V, 0mA < I
LOAD
< 300mA
%0.8 2.0
3/5 = 3V, -20µA < REF load < 250µA, C
REF
= 0.22µF
Reference-Voltage Regulation
V1.23 1.25 1.27No REF load, C
REF
= 0.1µF
60
I
LOAD
= 0mA, 3/5 = 3V, LBI = 1.25V, V
OUT
= 3.47V,
FB = 1.3V (MAX757 only)
µA
V
60Output set for 3.3V
1.1 1.8
I
LOAD
= 10mA
Minimum Start-Up Supply Voltage
4.8 5.0 5.2
2V < V
IN
< 3V
Reference Voltage
3.17 3.30 3.43 V
4.8 5.0 5.2
Output Voltage
UNITSMIN TYP MAXCONDITIONSPARAMETER
V0.7
I
LOAD
= 20mA
Minimum Operating Supply
Voltage (once started)
MAX756/MAX757
2
Maxim Integrated
3.3V/5V/Adjustable-Output,
Step-Up DC-DC Converters
MINIMUM START-UP INPUT VOLTAGE
vs. LOAD CURRENT
MAX756-7
LOAD CURRENT (mA)
START-UP INPUT VOLTAGE (V)
10 100
1000
1
1.8
1.6
1.4
1.2
1.0
0.8
3.3V MODE
40
0.1 10 1000
EFFICIENCY vs. LOAD CURRENT
3.3V OUTPUT MODE
MAX756-1
LOAD CURRENT (mA)
EFFICIENCY (%)
60
80
90
50
70
1 100
V
IN
= 2.0V
V
IN
= 1.2V
40
0.1 10 1000
EFFICIENCY vs. LOAD CURRENT
5V OUTPUT MODE
MAX756-2
LOAD CURRENT (mA)
EFFICIENCY (%)
60
80
90
50
70
1 100
V
IN
= 3.3V
V
IN
= 2.5V
V
IN
= 1.25V
800
0
02
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
200
600
MAX756-3
INPUT VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (mA)
4
400
100
300
500
700
13
5
3.3V MODE
5V MODE
1M
10
10μ 10m 1
SWITCHING FREQUENCY
vs. LOAD CURRENT
100
MAX756-4
LOAD CURRENT (A)
SWITCHING FREQUENCY (Hz)
1k
10k
100k
100μ 1m 100m
5V MODE
3.3V MODE
V
IN
= 2.5V
0
2
QUIESCENT CURRENT
vs. INPUT VOLTAGE
MAX756-5
INPUT VOLTAGE (V)
QUIESCENT CURRENT (μA)
4
100
200
300
400
500
1
3
5
V
OUT
= 3.3V
V
OUT
= 5V
CURRENT MEASURED AT V
IN
50
0
12 5
SHUTDOWN QUIESCENT CURRENT
vs. INPUT VOLTAGE
20
MAX756-6
INPUT VOLTAGE (V)
SHUTDOWN QUIESCENT CURRENT (μA)
4
40
10
30
3
CURRENT MEASURED AT V
IN
10
0
0
REFERENCE VOLTAGE
LOAD REGULATION
2
8
MAX756-8
LOAD CURRENT (μA)
VREF LOAD REGULATION (mV)
6
4
50 100 150 200
250
V
OUT
= 3.3V
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
MAX756/MAX757
Maxim Integrated
3
P1-P3P4-P6P7-P9

MAX756ESA+

Mfr. #:
Buy MAX756ESA+
Manufacturer:
Maxim Integrated
Description:
Switching Voltage Regulators 3.3/5/AdjV-Out Step Up DC/DC Converter
Lifecycle:
New from this manufacturer.
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