|
|
Part: MAX756-1
Category:
Power Management
-> Battery Management
Description: MAX756, MAX757 3.3V/5V, High-Efficiency, Step-up DC-DC Converters
Company: Maxim Integrated Products
Datasheet: Download MAX756-1 datasheet File size : 319 kB
Request For quote: Find where to buy MAX756-1
Datasheet text preview:
19-0113; Rev. 2; 1/95
UAL IT MAN TION K T VALUA A SHEE E T WS DA FOLLO
3.3V/5V/Adjustable-Output, Step-Up DC-DC Converters
____________________________Features
o Operates Down to 0.7V Input Supply Voltage o 87% Efficiency at 200mA o 60µA Quiescent Current o 20µA Shutdown Mode with Active Reference and LBI Detector o 500kHz Maximum Switching Frequency o ±1.5% Reference Tolerance Over Temperature o Low-Battery Detector (LBI/LBO) o 8-Pin DIP and SO Packages
_______________General Description
The MAX756/MAX757 are CMOS step-up DC-DC switching regulators for small, low input voltage or battery-powered systems. The MAX756 accepts a positive input voltage down to 0.7V and converts it to a higher pinselectable 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.
MAX756/MAX757
______________Ordering Information
PART MAX756CPA MAX756CSA MAX756C/D MAX756EPA MAX756ESA MAX757CPA MAX757CSA MAX757C/D MAX757EPA MAX757ESA 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 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 PIN-PACKAGE 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO
________________________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
* Dice are tested at TA = +25°C only.
__________Typical Operating Circuit
2 INPUT V to VOUT
_________________Pin Configurations
T O P VIEW
SHDN 1 2 8 7 LX GND OUT LBI
150µF 5 1 LBI SHDN LX 8
22µH
5 OUTPUT V at 200mA 3 or 1N5817 .3V at 300mA 100µF
3/5
REF 3 LBO 4
MAX756
6 5
DIP/SO
SHDN FB 1 2 8 7
2
MAX756
3/5 OUT
6
LX GND OUT LBI
3 0.1µF
REF GND 7
LBO
4
D LOW-BATTERY ETECTOR OUTPUT
REF 3 LBO 4
MAX757
6 5
DIP/SO
________________________________________________________________ Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
3.3V/5V/Adjustable-Output, Step-Up DC-DC Converters MAX756/MAX757
ABSOLUTE MAXIMUM RATINGS
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, (VOUT + 0.3V) Reference Current (IREF) ....2.5mA Continuous Power Dissipation (TA = +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
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
(Circuits of Figure 1 and Typical Operating Circuit, VIN = 2.5V, ILOAD = 0mA, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER Output Voltage CONDITIONS MAX756, 3/5 = 0V, 0mA < ILOAD < 200mA 2V < VIN < 3V MAX756, 3/5 = 3V, 0mA < ILOAD < 300mA MAX757, VOUT = 5V, 0mA < ILOAD < 200mA Minimum Start-Up Supply Voltage ILOAD = 10mA Minimum Operating Supply Voltage (once started) Quiescent Supply Current in 3.3V Mode (Note 1) Battery Quiescent Current Measured at VIN in Figure 1 Shutdown Quiescent Current (Note 1) Reference Voltage Reference-Voltage Regulation LBI Input Threshold LBI Input Hysteresis LBO Output Voltage Low LBO Output Leakage Current SHDN, 3/5 Input Voltage Low SHDN, 3/5 Input Voltage High SHDN, 3/5, FB, LBI Input Current FB Voltage Output Voltage Range LBI = 1.25V, FB = 1.25V, SHDN = 0V or 3V, 3/5 = 0V or 3V MAX757 MAX757, ILOAD = 0mA (Note 2) 1.22 2.7 1.25 1.6 ±100 1.28 5.5 ISINK = 2mA LBO = 5V ILOAD = 20mA ILOAD = 0mA, 3/5 = 3V, LBI = 1.25V, VOUT = 3.47V, FB = 1.3V (MAX757 only) Output set for 3.3V SHDN = 0V, LBI = 1.25V, 3/5 = 3V, VOUT = 3.47V, FB = 1.3V (MAX757 only) No REF load, CREF = 0.1µF 3/5 = 3V, -20µA < REF load < 250µA, CREF = 0.22µF With falling edge 1.23 1.22 60 MIN 4.8 3.17 4.8 TYP 5.0 3.30 5.0 1.1 0.7 60 MAX 5.2 3.43 5.2 1.8 V V µA UNITS V
µA
20 1.25 0.8 1.25 25
40 1.27 2.0 1.28 0.4 1 0.4
µA V % V mV V µA V V nA V V
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.
2
_______________________________________________________________________________________
3.3V/5V/Adjustable-Output, Step-Up DC-DC Converters
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT 3.3V OUTPUT MODE
MAX756-1
MAX756/MAX757
EFFICIENCY vs. LOAD CURRENT 5V OUTPUT MODE
VIN = 3.3V
MAX756-2
MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE
700 600 500 400 300 200 100 3.3V MODE 5V MODE
MAX756-3
90 VIN = 2.0V 80 VIN = 1.2V EFFICIENCY (%)
90
800 MAXIMUM OUTPUT CURRENT (mA)
80 VIN = 2.5V EFFICIENCY (%) 70 VIN = 1.25V
70
60
60
50
50
40 0.1 1 10 100 1000 LOAD CURRENT (mA)
40 0.1 1 10 100 1000 LOAD CURRENT (mA)
0 0 1 2 3 4 5 INPUT VOLTAGE (V)
SWITCHING FREQUENCY vs. LOAD CURRENT
MAX756-4
QUIESCENT CURRENT vs. INPUT VOLTAGE
MAX756-5
SHUTDOWN QUIESCENT CURRENT vs. INPUT VOLTAGE
SHUTDOWN QUIESCENT CURRENT (µA) CURRENT MEASURED AT VIN 40
MAX756-6
1M
500 CURRENT MEASURED AT VIN QUIESCENT CURRENT (µA) 400
50
SWITCHING FREQUENCY (Hz)
100k
5V MODE
10k 3.3V MODE
300
VOUT = 5V
30
1k
200
20
100 VIN = 2.5V 10
100 VOUT = 3.3V 0 10µ 100µ 1m 10m 100m 1 1 2 3 INPUT VOLTAGE (V) 4 5 LOAD CURRENT (A)
10 0 1 2 3 INPUT VOLTAGE (V) 4 5
MINIMUM START-UP INPUT VOLTAGE vs. LOAD CURRENT
MAX756-7
REFERENCE VOLTAGE LOAD REGULATION
MAX756-8
1.8
10
START-UP INPUT VOLTAGE (V)
1.6
VREF LOAD REGULATION (mV)
8
1.4
6
1.2
4 VOUT = 3.3V
1.0 3.3V MODE 0.8 1 10 100 1000 LOAD CURRENT (mA)
2
0 0 50 100 150 200 250 LOAD CURRENT (µA)
_________________________________________________________________________________________________
3
Others parts begin by ma
|
|
|
