LT3502/LT3502A - analog.com

1 LT3502/LT3502A . , 500mA. Step-Down Regulators in 2mm 2mm DFN and MS10. Features Description n 3V to 40V Input Voltage Range The LT 3502/LT3502A are current mode PWM step-down n 500mA Output Current DC/DC converters with an internal 500mA power switch, n Switching Frequency: (LT3502A), in tiny 8-lead 2mm 2mm DFN and 10-lead MS10. (LT3502) packages. The wide input voltage range of 3V to 40V makes n 800mV Feedback Voltage the LT3502/LT3502A suitable for regulating power from a n Short-Circuit Robust wide variety of sources, including 24V industrial supplies n Soft-Start and automotive batteries. Its high operating frequency n Low Shutdown Current: <2 A allows the use of tiny, low cost inductors and capacitors, n Internally Compensated resulting in a very small solution.

2 Constant frequency n Internal Boost Diode above the AM band avoids interfering with radio reception, n Thermally Enhanced 2mm 2mm 8-Lead DFN making the LT3502A particularly suitable for automotive and 10-Lead MS10 Package applications. Cycle-by-cycle current limit and frequency foldback Applications provide protection against shorted outputs. Soft-start and frequency foldback eliminates input current surge n Automotive Systems during start-up. DA current sense provides further protec- n Battery-Powered Equipment tion in fault conditions. An internal boost diode reduces n Wall Transformer Regulation component count. n Distributed Supply Regulation L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.

3 Typical Application Step-Down Converter LT3502A 12 VIN Efficiency 90. BD 80. VIN 5 VOUT VIN BOOST. TO 40V 70. 1 F F H. VOUT 60. EFFICIENCY (%). SW LT3502A 500mA 50. DA 40. 30. OFF ON SHDN FB. GND 10k 20. 10 F. 10. 3502 TA01a 0. 0 LOAD CURRENT (A). 3502 TA01b 3502fd 1. LT3502/LT3502A . Absolute Maximum Ratings (Note 1). Input Voltage (VIN)..40V BD BOOST Operating Junction Temperature Range (Note 2). BOOST Pin Above SW LT3502AE, 40 C to 125 C. FB LT3502AI, 40 C to 125 C. SHDN Storage Temperature 65 C to 150 C. Pin Configuration TOP VIEW. VIN 1 8 SW TOP VIEW. SW 1 10 VIN. BD 2 7 BOOST. 9 BOOST 2 9 NC. FB 3 6 DA NC 3 8 BD. DA 4 7 FB. SHDN 4 5 GND GND 5 6 SHDN. MS PACKAGE. DC PACKAGE. 10-LEAD PLASTIC MSOP. 8-LEAD (2mm 2mm) PLASTIC DFN. JA = 110 C/W. JA = 102 C/W. EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB.

4 Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE. LT3502 EDC#PBF LT3502 EDC#TRPBF LCLV 8-Lead 2mm 2mm Plastic DFN 40 C to 125 C. LT3502 IDC#PBF LT3502 IDC#TRPBF LCLV 8-Lead 2mm 2mm Plastic DFN 40 C to 125 C. LT3502 AEDC#PBF LT3502 AEDC#TRPBF LCLT 8-Lead 2mm 2mm Plastic DFN 40 C to 125 C. LT3502 AIDC#PBF LT3502 AIDC#TRPBF LCLT 8-Lead 2mm 2mm Plastic DFN 40 C to 125 C. LT3502 EMS#PBF LT3502 EMS#TRPBF LTDTR 10-Lead Plastic MSOP 40 C to 125 C. LT3502 IMS#PBF LT3502 IMS#TRPBF LTDTR 10-Lead Plastic MSOP 40 C to 125 C. LT3502 AEMS#PBF LT3502 AEMS#TRPBF LTDTS 10-Lead Plastic MSOP 40 C to 125 C. LT3502 AIMS#PBF LT3502 AIMS#TRPBF LTDTS 10-Lead Plastic MSOP 40 C to 125 C. Consult LTC Marketing for parts specified with wider operating temperature ranges.

5 *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: For more information on tape and reel specifications, go to: 3502fd 2. LT3502/LT3502A . Electrical The Characteristics l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25 C. VIN = 10V, VSHDN = 5V, VBOOST = 15V. PARAMETER CONDITIONS MIN TYP MAX UNITS. Undervoltage Lockout 3 V. Quiescent Current at Shutdown VSHDN = 0V 2 A. Quiescent Current Not Switching 2 mA. Feedback Voltage 2mm 2mm DFN l V. 2mm 2mm DFN V. MS10 l V. MS10 V. Reference Voltage Line Regulation %/V. FB Pin Bias Current (Note 5) l 15 50 nA.

6 Switching Frequency IDA < 500mA (LT3502A) MHz IDA < 500mA (LT3502A) l MHz IDA < 500mA (LT3502) MHz IDA < 500mA (LT3502) l MHz Maximum Duty Cycle 100mA Load (LT3502A) 70 80 %. 100mA Load (LT3502) 80 90 %. Switch VCESAT ISW = 500mA 450 mV. Switch Current Limit (Note 3) A. Switch Active Current SW = 10V (Note 4) 95 130 A. SW = 0V (Note 5) 8 30 A. BOOST Pin Current ISW = 500mA 10 13 mA. Minimum BOOST Voltage Above Switch ISW = 500mA V. BOOST Schottky Forward Drop IOUT = 100mA 1 V. DA Pin Current to Stop OSC 500 650 mA. SHDN Bias Current VSHDN = 5V 55 80 A. VSHDN = 0V 1 A. SHDN Input Voltage High 2 V. SHDN Input Voltage Low V. Note 1: Stresses beyond those listed under Absolute Maximum Ratings with statistical process controls. The LT3502 IDC and LT3502 AIDC are may cause permanent damage to the device.

7 Exposure to any Absolute guaranteed over the 40 C to 125 C operating junction temperature Maximum Rating condition for extended periods may affect device range. reliability and lifetime. Note 3: Current limit guaranteed by design and/or correlation to static test. Note 2. The LT3502 EDC and LT3502 AEDC are guaranteed to meet Slope compensation reduces current limit at higher duty cycle. performance specifications from 0 C to 125 C junction temperature Note 4: Current flows into pin. range. Specifications over the 40 C to 125 C operating junction Note 5: Current flows out of pin. temperature range are assured by design, characterization and correlation 3502fd 3. LT3502/LT3502A . Typical Performance Characteristics (TA = 25 C unless otherwise noted). LT3502A Efficiency LT3502A 5 VOUT Efficiency LT3502 Efficiency 90 90 100.

8 12 VIN 5 VIN. 80 80 90. 24 VIN. 70 12 VIN 80. 70. 24 VIN 24 VIN. 70. 60 60 12 VIN. EFFICIENCY (%). EFFICIENCY (%). EFFICIENCY (%). 60. 50 50. 50. 40 40. 40. 30 30. 30. 20 20 20. 10 10 10. 0 0 0. 0 0 0 LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A). 3502 G01 3502 G02 3502 G03. LT3502A Maximum Load Current LT3502A Maximum Load Current LT3502 5 VOUT Efficiency VOUT = , L = H VOUT = 5V, L = 10 H. 100 90 12 VIN TYPICAL TYPICAL. 80 24 VIN. 70 MINIMUM LOAD CURRENT (A). LOAD CURRENT (A). MINIMUM. EFFICIENCY (%). 60 50 40 30 20 10 0 0 0. 0 0 10 20 30 40 0 10 20 30 40. LOAD CURRENT (A) VIN (V) VIN (V). 3502 G04 3502 G05 3502 G06. LT3502 Maximum Load Current LT3502 Maximum Load Current VOUT = , L = 15 H VOUT = 5V, L = 22 H Switch Voltage Drop 700. TYPICAL TYPICAL 600.

9 MINIMUM MINIMUM 500. LOAD CURRENT (A). LOAD CURRENT (A). 40 C. 25 C. VCE (mV). 400. 125 C. 300. 200. 100. 0 0 0. 0 10 20 30 40 0 10 20 30 40 0 VIN (V) VIN (V) SWITCH CURRENT (A). 3502 G07 3502 G08 3502 G09. 3502fd 4. LT3502/LT3502A . Typical Performance Characteristics (TA = 25 C unless otherwise noted). UVLO Switching Frequency Soft-Start (SHDN). LT3502A SWITCH CURRENT LIMIT (A). FREQUENCY (MHz). VIN (V). LT3502 0. 0 0 50 0 50 100 150 50 0 50 100 150 0 200 400 600 800 1000 1200 1400 1600. TEMPERATURE ( C) TEMPERATURE ( C) SHDN PIN VOLTAGE (mV). 3502 G10 3502 G11 3502 G12. SHDN Pin Current Switch Current Limit Switch Current Limit 300 250 SW PEAK CURRENT LIMIT. SHDN PIN CURRENT ( A). LT3502. CURRENT LIMIT (A). CURRENT LIMIT (A). 200 DA VALLEY CURRENT LIMIT. LT3502A.

10 150 100 50 0 0 0. 0 5 10 15 20 25 30 35 40 45 50 0 50 100 150 0 50 100. SHDN PIN VOLTAGE (V) TEMPERATURE ( C) DUTY CYCLE (%). 3502 G13 3502 G14 3502 G15. LT3502A Maximum VIN for Full LT3502A Maximum VIN for Full LT3502 Maximum VIN for Full Frequency (VOUT = ) Frequency (VOUT = 5V) Frequency (VOUT = ). 45 45 45. 40 TA = 25 C 40 40. 35 35 35. TA = 85 C. 30 30 30. TA = 25 C TA = 25 C. 25 25 25. VIN (V). VIN (V). VIN (V). TA = 85 C TA = 85 C. 20 20 20. 15 15 15. 10 10 10. 5 5 5. 0 0 0. 0 0 0 LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A). 3502 G16 3502 G17 3502 G18. 3502fd 5. LT3502/LT3502A . Typical Performance Characteristics (TA = 25 C unless otherwise noted). LT3502A Typical Minimum Input LT3502A Typical Minimum Input LT3502 Typical Minimum Input Voltage (VOUT = ) Voltage (VOUT = 5V) Voltage (VOUT = ).