Description
LTC3528/LTC3528B 1A, 1MHz Synchronous Step-Up DC/DC Converters in 3mm × 2mm DFN FEATURES Delivers 3.3V at 200mA from a Single Alkaline/ NiMH Cell or 3.3V at 400mA from Two Cells ■ V Start-Up Voltage: 700mV IN ■ 1.6V to 5.25V V OUT Range www.DataSheet4U.com ■ Up to 94% Efficiency ■ Output Disconnect ■ 1MHz Fixed Frequency Operation ■ V >V IN OUT Operation ■ Integrated Soft-Start ■ Current Mode Control with Internal Compensation ■ Burst Mode® Operation with 12μA Quiescent Current (LTC3528) ■ Low Noise PWM Operation (LTC3528B) ■ Internal Synchronous Rectifier ■ Logic Controlled Shutdown: <1μA ■ Anti-Ringing Control ■ Low Profile (3mm × 2mm × 0.75mm) DFN Package ■ DESCRIPTION The LTC®3528/LTC3528B are synchronous, fixed frequency step-up DC/DC converters with output disconnect. High efficiency synchronous rectification, in addition to a 700mV start-up voltage and operation down to 500mV once started, provides longer run-time for single or multiple cell battery-powered products. A switching frequency of 1MHz minimizes solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. The current mode PWM is internally compensated, simplifying the design process. The LTC3528 enters Burst Mode operation at light loads, while the LTC3528B features continuous switching at light loads. Anti-ringing circuitry reduces EMI by damping the inductor in discontinuous mode. Additional features include a low shutdown current, open-drain power good output, shortcircuit protection and thermal overload protection. The LTC3528/LTC3528B are offered in an 8-lead 3mm × 2mm × 0.75mm DFN package. , LT LTC, LTM and Burst Mode are registered trademarks of Linear Technology , Corporation. All other trademarks are the property of their respective owners. APPLICATIONS ■ ■ ■ ■ ■ Medical Instruments Flash-Based MP3 Players Noise Canceling Headphones Wireless Mice Bluetooth Headsets TYPICAL APPLICATION 100 4.7μH 90 SW VIN 1.8V TO 3.2V 4.7μF VIN VOUT 499k FB 287k 3528 TA01a Efficiency and Power Loss VOUT = 3.3V VIN = 2.4V 1000 100 EFFICIENCY (%) VOUT 3.3V 400mA 10μF 80 EFFICIENCY 70 60 POWER LOSS 50 0.1 40 30 0.01 0.01 1000 3528 TA01b POWER LOSS (mW) 10 LTC3528 PGOOD 33pF 1 OFF ON SHDN GND 0.1 1 10 100 LOAD CURRENT (mA) 3528fa 1 LTC3528/LTC3528B ABSOLUTE MAXIMUM RATINGS (Note 1) PIN CONFIGURATION TOP VIEW SHDN 1 FB 2 PGOOD 3 VOUT 4 9 8 VIN 7 SGND 6 PGND 5 SW VIN Voltage ................................................... –0.3V to 6V SW Voltage DC............................................................ –0.3V to 6V Pulsed < 100ns ........................................ –0.3V to 7V SHDN, FB Voltage ........................................ –0.3V to 6V VOUT ............................................................. –0.3V to 6V PGOOD......................................................... –0.3V to 6V Operating Temperature Range www.DataSheet4U.com 5) .............................................. –40°C to 85°C (Notes 2, Storage Temperature Range................... –65°C to 125°C DDB PACKAGE 8-LEAD (3mm × 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 76°C/W (NOTE 6) EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH LTC3528EDDB#PBF LTC3528BEDDB#PBF TAPE AND REEL LTC3528EDDB#TRPBF LTC3528BEDDB#TRPBF PART MARKING LCYD LDDG PACKAGE DESCRIPTION 8-Lead (3mm × 2mm) Plastic DFN 8-Lead (3mm × 2mm) Plastic DFN TEMPERATURE RANGE –40°C to 85°C –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ ELECTRICAL CHARACTERISTICS PARAMETER Minimum Start-Up Voltage Output Voltage Adjust Range TA = 0°C to 85°C Feedback Voltage Feedback Input Current Quiescent Current—Shutdown Quiescent Current—Active Quiescent Current—Burst P-Channel MOSFET Switch Leakage Current N-Channel MOSFET Switch On Resistance P-Channel MOSFET Switch On Resistance N-Channel MOSFET Current Limit Current Limit Delay Time to Output Maximum Duty Cycle Minimum Duty Cycle Frequency (Note 3) VFB = 1.15V VFB = 1.3V (Note 7) VFB = 1.3V CONDITIONS ILOAD = 1mA The ● denotes the specifications which apply over the specified operating temperature range of –40°C to 85°C, otherwise specifications are at TA = 25°C. VIN = 1.2V, VOUT = 3.3V, unless otherwise noted. MIN ● ● ● TYP 0.70 MAX 0.88 5.25 5.25 UNITS V V V V nA μA μA μA μA μA Ω Ω A ns % 1.7 1.6 1.170 1.200 1 0.01 300 12 0.1 0.1 0.175 0.250 1.230 50 1 500 20 10 10 VSHDN = 0V, Not Including Switch Leakage, VOUT = 0V Measured on VOUT, Nonswitching (Note 4) Measured on VOUT, FB > 1.230V VSW = 5V, VOUT = 0V N-Channel MOSFET Switch Leakage Current VSW = 5V ● 1.0 88 0.7 1.5 60 93 0 1.0 1.3 ● ● ● % MHz 3528fa 2 LTC3528/LTC3528B ELECTRICAL CHARACTERISTICS PARAMETER SHDN Input High Voltage SHDN Input Low Voltage SHDN Input Current PGOOD Threshold Percentage PGOOD Low Voltage PGOOD Leakage Current www.DataSheet4U.com The ● denotes the specifications which apply over the specified operating temperature range of –40°C to 85°C, otherwise specifications are at TA = 25°C. VIN = 1.2V, VOUT = 3.3V, unless otherwise noted. CONDITIONS MIN 0.88 0.25 VSHDN = 1.2V Referenced to Feedback Voltage Falling IPGOOD = 1mA VOUT = 1.6V, IPGOOD = 1mA VPGOOD = 5.5V –7 0.3 –10 0.05 0.05 0.01 1 –13 0.1 0.2 1 TYP MAX UNITS V V μA % V V μA Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC3528E is guaranteed to meet performance specifications from 0°C to 85°C. Specifications over –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: Specification is guaranteed by design and not 100% tested in production. Note 4: Current measurements are made when the output is not switching. Note 5: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may result in device degradation or failure. Note 6: Failure to solder the exposed backside of the package to the PC board ground plane will result in a thermal resistance much higher than 76°C/W. Note 7: The IC is tested in a feedback loop to make the measurement. TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs Load Current and VIN for VOUT = 1.8V (LTC3528) 100 90 80 EFFICIENCY (%) 70 60 50 40 30 20 10 0 0.01 0.1 VIN = 1V VIN = 1.2V VIN = 1.5V 10 100 1 LOAD CURRENT (mA) 0.1 POWER LOSS 1 10 EFFICIENCY 100 POWER LOSS (mW) EFFICIENCY (%) 1000 100 90 80 70 60 50 40 30 20 10 0 0.01 (TA = 25°C unless otherwise noted) Efficiency vs Load Current and VIN for VOUT = 3V (LTC3528) EFFICIENCY 1000 100 POWER LOSS (mW) 10 POWER LOSS 1 0.01 1000 VIN = 1V VIN = 1.5V VIN = 2.4V 0.1 10 100 1 LOAD CURRENT (mA) 0.1 0.01 1000 3528 G01 3528 G26 3528fa 3 LTC3528/LTC3528B TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs Load Current and VIN for VOUT = 3.3V (LTC3528) 100 EFFICIENCY 90 100 80 EFFICIENCY (%) 70 60 50 40 30 0.01 VIN = 1.2V VIN = 1.8V VIN = 2.4V VIN = 3V 0.1 1 10 100 LOAD CURRENT (mA) 3528 G02 (TA = 25°C unless otherwise noted) No-Load Input Current vs VIN (LTC3528) 1000 130 110 100 POWER LOSS (mW) 90 IIN (μA) 70 50 30 10 1 2 3 VIN (V) 4 5 3528 G04 Efficiency vs Load Current and VIN for VOUT = 5V (LTC3528) 1000 100 EFFICIENCY 90 80 EFFICIENCY (%) 70 10 60 50 40 30 0.01 VIN = 1.2V VIN = 2.4V VIN = 3.6V VIN = 4.2V 0.1 1 10 100 LOAD CURRENT (mA) 3528 G03 POWER LOSS (mW) 10 POWER LOSS 1 www.DataSheet4U.com POWER LOSS 1 0.1 VOUT = 1.8V VOUT = 3V VOUT = 3.3V VOUT = 5V 0.01 1000 0.1 1000 Maximum Output Current vs VIN 800 700 600 10000 Minimum Load Resistance During Start-Up vs VIN 130 120 110 1000 DELAY (μs) RLOAD (Ω) 100 90 80 70 Start-Up Delay Time vs VIN IOUT (mA) 500 400 300 200 100 0 1 1.5 2 3 2.5 VIN (V) VOUT = 1.8V VOUT = 3.3V VOUT = 5V 3.5 4 4.5 3528 G05 100 60 10 0.7 0.8 VIN (V) 3528 G06 50 0.9 1 1 1.5 2 3 2.5 VIN (V) 3.5 4 4.5 3528 G07 Burst Mode Threshold Current vs VIN 40 VOUT = 1.8V 50 Burst Mode Threshold Current vs VIN VOUT = 3V 60 Burst Mode Threshold Current vs VIN VOUT = 3.3V RISING 30 RISING IOUT (mA) IOUT (mA) 40 RISING FALLING 20 IOUT (mA) 30 40 20 FALLING 10 FALLING 20 10 0 1 1.1 1.3 1.2 VIN (V) 1.4 1.5 3528 G08 0 1 1.5 VIN (V) 2 2.5 3528 G09 0 1 1.5 2 VIN (V) 2.5 3 3528 G10 3528fa 4 LTC3528/LTC3528B TYPICAL PERFORMANCE CHARACTERISTICS Burst Mode Threshold Current vs VIN 60 VOUT = 5V FREQUENCY CHANGE (%) 0.50 0.25 0 –0.25 RDS(ON) (mΩ) –0.50 –0.75 –1.00 –1.25 –1.50 –1.75 –2.00 0 1 2 VIN (V) 3528 G11 (TA = 25°C unless otherwise noted) Oscillator Frequency Change vs VOUT 450 NORMALIZED TO VOUT = 3V 400 350 300 250 200 RDS(ON) vs VOUT 40 IOUT (mA) RISING FALLING 20 PMOS www.DataSheet4U.com NMOS 150 100 1.5 –2.25 3 4 1.5 2 2.5 3.5 3 VOUT (V) 4 4.5 5 2 2.5 3.5 3 VOUT (V) 4 4.5 5 3528 G12 3528 G13 Oscillator Frequency Change vs Temperature 5 4 FREQUENCY CHANGE (%) 3 2 CHANGE (%) NORMALIZED TO 25°C 30 RDS(ON) Change vs Temperature 1.200 VFB vs Temperature 20 1.195 0 –1 –2 –3 –4 –5 –50 –30 30 –10 10 50 TEMPERATURE (°C) 70 90 0 1.185 –10 –20 –50 VFB (V) 1 10 1.190 –30 30 –10 10 50 TEMPERATURE (°C) 70 90 1.180 –50 –30 50 –10 10 30 TEMPERATURE (°C) 70

Part Number
LTC3528B

Free Sample / Buy Component / Product Information
Locate Part LTC3528B

Datasheet
Locate DataSheet

LTC3528B Cross Reference : Jump New Window
Get Cross-Reference Datasheet