LT8610A

LT8610A/LT8610AB Series (Rev. B)

Document overview

• Manufacturer or author: Analog Devices Inc.
• PDF pages: 26

Technical content

Rev. CFor more information www.analog.comDocument Feedback TYPICAL APPLICATION FEATURES DESCRIPTION 42V, 3.5A Synchronous Step-Down Regulator with 2.5µA Quiescent Current The LT®8610A/LT8610AB series are compact, high ef- ficiency, high speed synchronous monolithic step-down switching regulators that consume only 2.5µA of quies- cent current. Compared to the LT8610, they have higher maximum output currents of 3.5A and a faster minimum switch-on time of 30ns. The LT8610A has the same low ripple burst mode performance of the LT8610, while the LT8610AB has even higher light load efficiency. The other features of the LT8610 remain unchanged in the LT8610A/LT8610AB series. A SYNC pin allows synchroni- zation to an external clock. The EN/UV pin has an accurate 1V threshold for VIN undervoltage lockout or shut down. A capacitor on the TR/SS pin programs the output voltage ramp rate during startup. The PG flag signals when VOUT is within ±9% of the programmed output voltage as well as fault conditions. OUTPUT CURRENT MINIMUM ON TIME 1mA LOAD EFFICIENCY** LT8610* 2.5A 50ns 82% LT8610A 3.5A 30ns 82% LT8610AB 3.5A 30ns 91% *See LT8610 data sheet. **VIN = 12V, VOUT = 3.3V, L = 4.7µH 5V 3.5A Step-Down Converter

APPLICATIONS

n LT8610 Feature Set, Plus:

3.5 A Maximum Output Current

Fast 30ns Minimum Switch-On Time Improved Burst Mode Efficiency (LT8610AB Only) Improved EMI n Wide Input Voltage Range: 3.4V to 42V n Ultralow Quiescent Current Burst Mode® Operation: 2.5μ A IQ Regulating 12VIN to 3.3VOUT n Fixed Output Voltages: 3.3V, 5V n Output Ripple < 10mVP-P (LT8610A Only) n High Efficiency Synchronous Operation: 95% Efficiency at 1A, 5VOUT from 12VIN 93% Efficiency at 1A, 3.3VOUT from 12VIN n Low Dropout Under All Conditions: 200mV at 1A n Safely Tolerates Inductor Saturation in Overload n Adjustable and Synchronizable Frequency: 200kHz to 2.2MHz n Accurate 1V Enable Pin Threshold n Output Soft-Start and T racking n Small Thermally Enhanced 16-Lead MSOP Package n AEC-Q100 Qualified for Automotive Applications n Automotive and Industrial Supplies n GSM Power Supplies BSTVIN EN/UV PG SYNC INTVCC TR/SS RT SWL T8610AB-5 GND BIAS 8610ab TA01a VOUT 0.1µF VOUT 3.5A 4.7µF VIN 5.5V TO 42V 1µF 10nF 4.7µH fSW = 700kHz 60.4k 47µF LT8610AB Efficiency at 5VOUT 0.1 1 100010010 LOAD CURRENT (mA) EFFICIENCY (%) 100 8610ab TA01b VIN = 12V VIN = 24V VIN = 36V All registered trademarks and trademarks are the property of their respective owners.

Rev. C For more information www.analog.com ABSOLUTE MAXIMUM RATINGS Operating Junction Temperature Range (Note 2) (Note 1) ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8610AEMSE#PBF LT8610AEMSE#TRPBF 8610A 16-Lead Plastic MSOP –40°C to 125°C LT8610AEMSE-3.3#PBF LT8610AEMSE-3.3#TRPBF 610A33 16-Lead Plastic MSOP –40°C to 125°C LT8610AEMSE-5#PBF LT8610AEMSE-5#TRPBF 8610A5 16-Lead Plastic MSOP –40°C to 125°C LT8610AIMSE#PBF LT8610AIMSE#TRPBF 8610A 16-Lead Plastic MSOP –40°C to 125°C LT8610AIMSE-3.3#PBF LT8610AIMSE-3.3#TRPBF 610A33 16-Lead Plastic MSOP –40°C to 125°C LT8610AIMSE-5#PBF LT8610AIMSE-5#TRPBF 8610A5 16-Lead Plastic MSOP –40°C to 125°C LT8610AHMSE#PBF LT8610AHMSE#TRPBF 8610A 16-Lead Plastic MSOP –40°C to 150°C LT8610AHMSE-3.3#PBF LT8610AHMSE-3.3#TRPBF 610A33 16-Lead Plastic MSOP –40°C to 150°C LT8610AHMSE-5#PBF LT8610AHMSE-5#TRPBF 8610A5 16-Lead Plastic MSOP –40°C to 150°C LT8610ABEMSE#PBF LT8610ABEMSE#TRPBF 8610AB 16-Lead Plastic MSOP –40°C to 125°C LT8610ABEMSE-3.3#PBF LT8610ABEMSE-3.3#TRPBF 10AB33 16-Lead Plastic MSOP –40°C to 125°C LT8610ABEMSE-5#PBF LT8610ABEMSE-5#TRPBF 610AB5 16-Lead Plastic MSOP –40°C to 125°C LT8610ABIMSE#PBF LT8610ABIMSE#TRPBF 8610AB 16-Lead Plastic MSOP –40°C to 125°C LT8610ABIMSE-3.3#PBF LT8610ABIMSE-3.3#TRPBF 10AB33 16-Lead Plastic MSOP –40°C to 125°C LT8610ABIMSE-5#PBF LT8610ABIMSE-5#TRPBF 610AB5 16-Lead Plastic MSOP –40°C to 125°C LT8610ABHMSE#PBF LT8610ABHMSE#TRPBF 8610AB 16-Lead Plastic MSOP –40°C to 150°C LT8610ABHMSE-3.3#PBF LT8610ABHMSE-3.3#TRPBF 10AB33 16-Lead Plastic MSOP –40°C to 150°C LT8610ABHMSE-5#PBF LT8610ABHMSE-5#TRPBF 610AB5 16-Lead Plastic MSOP –40°C to 150°C LT8610A, LT8610AB LT8610A-3.3, LT8610A-5, LT8610AB-3.3, LT8610AB-5 SYNC TR/SS RT EN/UV VIN VIN NC GND FB PG BIAS INTVCC BST SW SW SW TOP VIEW GND MSE PACKAGE 16-LEAD PLASTIC MSOP θJA = 40°C/W , θJC(PAD) = 10°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB SYNC TR/SS RT EN/UV VIN VIN NC GND VOUT PG BIAS INTVCC BST SW SW SW TOP VIEW GND MSE PACKAGE 16-LEAD PLASTIC MSOP θJA = 40°C/W , θJC(PAD) = 10°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB PIN CONFIGURATION

Rev. CFor more information www.analog.com

ELECTRICAL CHARACTERISTICS

The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Input Voltage (Note 4) l 2.9 3.4 V VIN Quiescent Current VEN/UV = 0V l 1.0 1.0 µA µA VEN/UV = 2V, Not Switching, VSYNC = 0V l 1.7 1.7 µA µA VEN/UV = 2V, Not Switching, VSYNC = 2V 0.26 0.5 mA VIN Current in Regulation VOUT = 0.97V, VIN = 6V, Output Load = 100µA (LT8610A) VOUT = 0.97V, VIN = 6V, Output Load = 1mA (LT8610A) VOUT = 0.97V, VIN = 6V, Output Load = 100µA (LT8610AB) VOUT = 0.97V, VIN = 6V, Output Load = 1mA (LT8610AB) l l l l 210 210 350 350 µA µA µA µA VIN Current in Regulation VOUT = 3.3V, VIN = 8V, Output Load = 100µA (LT8610A-3.3) VOUT = 3.3V, VIN = 8V, Output Load = 1mA (LT8610A-3.3) VOUT = 3.3V, VIN = 8V, Output Load = 100µA (LT8610AB-3.3) VOUT = 3.3V, VIN = 8V, Output Load = 1mA (LT8610AB-3.3) VOUT = 5V, VIN = 8V, Output Load = 100µA (LT8610A-5) VOUT = 5V, VIN = 8V, Output Load = 1mA (LT8610A-5) VOUT = 5V, VIN = 8V, Output Load = 100µA (LT8610AB-5) VOUT = 5V, VIN = 8V, Output Load = 1mA (LT8610AB-5) l l l l l l l l 540 500 100 790 730 120 900 100 800 180 1200 150 1100 µA µA µA µA µA µA µA µA Feedback Reference Voltage (LT8610A/LT8610AB) VIN = 6V, ILOAD = 0.5A VIN = 6V, ILOAD = 0.5A l 0.964 0.958 0.970 0.970 0.976 0.982 V V Output Voltage (LT8610A-3.3/LT8610AB-3.3) VIN = 8V, ILOAD = 0.5A VIN = 8V, ILOAD = 0.5A l 3.28 3.26 3.30 3.30 3.32 3.34 V V Output Voltage (LT8610A-5/LT8610AB-5) VIN = 8V, ILOAD = 0.5A VIN = 8V, ILOAD = 0.5A l 4.97 4.94 5.00 5.00 5.03 5.06 V V Feedback Voltage Line Regulation (LT8610A/LT8610AB) VIN = 4V to 42V, ILOAD = 1A l 0.004 0.02 %/V Voltage Line Regulation (LT8610A-3.3/LT8610AB-3.3) VIN = 4V to 42V, ILOAD = 1A l 0.004 0.02 %/V Voltage Line Regulation (LT8610A-5/LT8610AB-5) VIN = 6V to 42V, ILOAD = 1A l 0.004 0.02 %/V Feedback Pin Input Current (LT8610A/LT8610AB) VFB = 1V –20 20 nA LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE AUTOMOTIVE PRODUCTS** LT8610AEMSE#WPBF LT8610AEMSE#WTRPBF 8610A 16-Lead Plastic MSOP –40°C to 125°C LT8610AIMSE#WPBF LT8610AIMSE#WTRPBF 8610A 16-Lead Plastic MSOP –40°C to 125°C LT8610AHMSE#WPBF LT8610AHMSE#WTRPBF 8610A 16-Lead Plastic MSOP –40°C to 150°C LT8610ABEMSE#WPBF LT8610ABEMSE#WTRPBF 8610AB 16-Lead Plastic MSOP –40°C to 125°C LT8610ABIMSE#WPBF LT8610ABIMSE#WTRPBF 8610AB 16-Lead Plastic MSOP –40°C to 125°C LT8610ABHMSE#WPBF LT8610ABHMSE#WTRPBF 8610AB 16-Lead Plastic MSOP –40°C to 150°C Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. **Versions of this part are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. These models are designated with a #W suffix. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models.

Rev. C For more information www.analog.com The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS MIN TYP MAX UNITS Internal Feedback Resistor Divider (LT8610A-3.3/LT8610AB-3.3) 14.3 MΩ Internal Feedback Resistor Divider (LT8610A-5/LT8610AB-5) 12.5 MΩ INTVCC Voltage ILOAD = 0mA, VBIAS = 0V ILOAD = 0mA, VBIAS = 3.3V 3.23 3.25 3.4 3.29 3.57 3.35 V V INTVCC Undervoltage Lockout 2.5 2.6 2.7 V BIAS Pin Current Consumption VBIAS = 3.3V, ILOAD = 1A, 2MHz 9 mA Minimum On-Time ILOAD = 1A, SYNC = 0V ILOAD = 1A, SYNC = 3.3V l l ns ns Minimum Off-Time 95 125 ns Oscillator Frequency RT = 221k, ILOAD = 1A RT = 60.4k, ILOAD = 1A RT = 18.2k, ILOAD = 1A l l l 180 665 1.85 210 700 2.00 240 735 2.15 kHz kHz MHz Top Power NMOS On-Resistance ISW = 1A 120 mΩ Top Power NMOS Current Limit LT8610A LT8610AB l l 6.7 6.7 A A Bottom Power NMOS On-Resistance VINTVCC = 3.4V, ISW = 1A 65 mΩ Bottom Power NMOS Current Limit VINTVCC = 3.4V 3.4 4.3 5.4 A SW Leakage Current VIN = 42V, VSW = 0V, 42V –1.5 1.5 µA EN/UV Pin Threshold EN/UV Rising l 0.94 1.0 1.06 V EN/UV Pin Hysteresis 40 mV EN/UV Pin Current VEN/UV = 2V –20 20 nA PG Upper Threshold Offset from VFB VFB Falling l 6 9.0 12 % PG Lower Threshold Offset from VFB VFB Rising l –12 –9.0 –6 % PG Hysteresis 1.3 % PG Leakage VPG = 3.3V –40 40 nA PG Pull-Down Resistance VPG = 0.1V l 680 2000 Ω SYNC Threshold SYNC Falling SYNC Rising 0.8 1.6 1.1 2.0 1.4 2.4 V V SYNC Pin Current VSYNC = 6V –40 40 nA TR/SS Source Current l 1.0 2.0 3.2 µA TR/SS Pull-Down Resistance Fault Condition, TR/SS = 0.1V 230 Ω 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 LT8610AE/LT8610ABE is guaranteed to meet performance specifications from 0°C to 125°C junction temperature. Specifications over the –40°C to 125°C operating junction temperature range are assured by design, characterization, and correlation with statistical process controls. The LT8610AI/LT8610ABI is guaranteed over the full –40°C to 125°C operating junction temperature range. The LT8610AH is guaranteed over the full –40°C to 150°C operating junction temperature range. High junction temperatures degrade operating lifetimes. Operating lifetime is derated at junction temperatures greater than 125°C. Note 3: This IC includes overtemperature protection that is intended to protect the device during overload conditions. Junction temperature will exceed 150°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature will reduce lifetime. Note 4: For fixed output voltage versions, minimum input voltage will be limited by output voltage.

Rev. CFor more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS LT8610AB Efficiency at 3.3VOUT LT8610A Efficiency at 5VOUT LT8610A Efficiency at 5VOUT LT8610A Efficiency at 3.3VOUT LT8610A Efficiency at 3.3VOUT LT8610A/LT8610AB Efficiency vs Frequency at 1A LT8610AB Efficiency at 5VOUT LT8610AB Efficiency at 5VOUT LT8610AB Efficiency at 3.3VOUT LOAD CURRENT (A) EFFICIENCY (%) 100 2 3 8610ab G01 0.5 1 1.5 3.52.5 fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH VIN = 12V VIN = 24V VIN = 36V LOAD CURRENT (mA) EFFICIENCY (%) 0.01 101 1000100 8610ab G03 0.1 100 VIN = 12V VIN = 24V VIN = 36V fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH 0 2 30.5 1 1.5 3.52.5 LOAD CURRENT (A) EFFICIENCY (%) 100 8610ab G02 VIN = 12V VIN = 24V VIN = 36V fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH 0.01 101 10001000.1 VIN = 12V VIN = 24V VIN = 36V LOAD CURRENT (mA) EFFICIENCY (%) 100 8610ab G04 fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH LOAD CURRENT (A) EFFICIENCY (%) 100 2 3 8610ab G42 0.5 1 1.5 3.52.5 fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH VIN = 12V VIN = 24V VIN = 36V LOAD CURRENT (mA) EFFICIENCY (%) 0.01 101 1000100 8610ab G43 0.1 100 VIN = 12V VIN = 24V VIN = 36V fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH 0 2 30.5 1 1.5 3.52.5 LOAD CURRENT (A) EFFICIENCY (%) 100 8610ab G44 VIN = 12V VIN = 24V VIN = 36V fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH 0.01 101 10001000.1 VIN = 12V VIN = 24V VIN = 36V LOAD CURRENT (mA) EFFICIENCY (%) 100 8610ab G45 fSW = 700kHz L = IHLP-2020BZ-01, 4.7µH SWITCHING FREQUENCY (MHz) 0.25 100 1.75 8610ab G05 EFFICIENCY (%) VIN = 12V VIN = 24V VOUT = 3.3V L = IHLP-2020BZ-01, 4.7µH

Rev. C For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS Line Regulation LT8610A No Load Supply Current LT8610AB No Load Supply Current No Load Supply Current Reference Voltage LT8610A-3.3 Output Voltage LT8610AB-3.3 Output Voltage EN Pin Thresholds Load Regulation TEMPERATURE (°C) –55

0.955 REFERENCE VOLTAGE (V)

0.958 0.964 0.967 0.970 0.985 0.976 5 65 95 125 8610ab G06 0.961 0.979 0.982 0.973 –25 35 155 TEMPERATURE (°C) –55

3.240 OUTPUT VOLTAGE (V)

3.255 3.285 3.300 3.315 3.360 3.345 5 65 95 125 8610ab G46 3.270 3.330 –25 35 155 TEMPERATURE (°C) –55

4.900 OUTPUT VOLTAGE (V)

4.925 4.975 5.000 5.025 5.100 5.075 5 65 95 125 8610ab G47 4.950 5.050 –25 35 155 TEMPERATURE (°C) –55 EN THRESHOLD (V) 8610ab G07 5–25 95 12535 155 0.95 0.96 0.98 0.99 1.00 1.02 0.97 1.01 EN RISING EN FALLING LOAD CURRENT (A) –0.25 CHANGE IN VOUT (%) –0.15 –0.05 0.05 0.5 1 1.5 2 8610ab G08 2.5 0.15 0.25 –0.20 –0.10 0.10 0.20 3.53 VOUT = 3.3V VIN = 12V INPUT VOLTAGE (V) CHANGE IN VOUT (%) 0.03 0.09 0.15 8610ab G09 –0.03 –0.09 0.06 0.12 –0.06 –0.12 –0.15 105 2015 30 35 4525 VOUT = 3.3V ILOAD = 0.5A INPUT VOLTAGE (V) INPUT CURRENT (µA) 0.5 1.5 2.0 2.5 5.0 3.5 10 20 25 40 8610ab G10 1.0 4.0 4.5 3.0 5 15 30 35 TESTED IN REGULATION 8610A: VOUT = 3.3V 8610A-3.3 8610A-5 8610A INPUT VOLTAGE (V) INPUT CURRENT (µA) 0.5 1.5 2.0 2.5 5.0 3.5 10 20 25 40 8610ab G48 1.0 4.0 4.5 3.0 5 15 30 35 TESTED IN REGULATION 8610AB: VOUT = 3.3V 8610AB-3.3 8610AB-5 8610AB TEMPERATURE (°C) –55 –25 INPUT CURRENT (µA) 5 65 95 8610ab G11 35 125 155 VOUT = 3.3V VIN = 12V IN REGULATION

Rev. CFor more information www.analog.com Top FET Current Limit vs Duty Cycle Top FET Current Limit Bottom FET Current Limit DUTY CYCLE CURRENT LIMIT (A) 3.5 4.0 4.5 0.6 1.0 8610ab G13 3.0 0.2 0.4 0.8 5.0 5.5 8.0 7.0 7.5 6.5 6.0 TEMPERATURE (°C) –55

4.50 CURRENT LIMIT (A)

4.75 5.00 5.25 5.50 5.75 6.00 6.25 6.50 6.75 7.00 –25 5 35 65 8610ab G14 95 125 30% DC TEMPERATURE (°C) –55

3.00 CURRENT LIMIT (A)

3.25 3.50 3.75 4.00 5.50 –25 5 35 65 8610ab G15 95 155125 4.25 4.50 4.75 5.00 5.25 TYPICAL PERFORMANCE CHARACTERISTICS Minimum On-Time Minimum Off-Time Dropout Voltage Switching Frequency Switch Drop Switch Drop TEMPERATURE (°C) –55 –25 SWITCH DROP (mV) 100 250 5 65 95 8610ab G40 200 150 35 125 155 TOP SW BOT SW SWITCH CURRENT = 1A SWITCH CURRENT (A) SWITCH DROP (mV) 150 200 250 450 8610ab G41 100 10.5 2.51.5 3 300 350 400 TOP SW BOT SW TEMPERATURE (°C) –55 31MINIMUM ON-TIME (ns) 5 65 95 125 8610ab G17 –25 35 155 VOUT = 3.3V VOUT = 0.97V ILOAD = 1.5A VSYNC = 0V TEMPERATURE (°C) –50 MINIMUM OFF-TIME (ns) 8610ab G18 –25 5 65 125 120 115 110 105 100 95 125 155 VOUT = 3.3V ILOAD = 0.5A LOAD CURRENT (A) DROPOUT VOLTAGE (V) 400 8610ab G19 200 600 800 300 100 500 700 0 0.5 1 1.5 2 2.5 3.53 TEMPERATURE (°C) –55 SWITCHING FREQUENCY (kHz) 730 8610ab G20 700 680 –25 5 65 670 660 740 RT = 60.4k 720 710 690 95 125 155

Rev. C For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS Soft-Start T racking Soft-Start Current PG High Thresholds RT Programmed Switching FrequencyPG Low Thresholds VIN UVLO TR/SS VOLTAGE (V) FB VOLTAGE (V) 0.8 1.0 1.2 0.6 1.0 8610ab G23 0.6 0.4 0.2 TEMPERATURE (°C) –50 SS PIN CURRENT (µA) 2.3 8610ab G24 2.0 1.8 –25 5 65 1.7 1.6 2.4 2.2 2.1 1.9 95 125 155 VSS = 0.5V TEMPERATURE (°C) –55 7.0 PG THRESHOLD OFFSET FROM VREF (%) 7.5 8.5 9.0 9.5 12.0 10.5 5 65 95 125 8610ab G25 8.0 11.0 11.5 10.0 –25 35 155 FB RISING FB FALLING SWITCHING FREQUENCY (MHz) 0.2 RT PIN RESISTOR (k/uni03A9) 150 200 250 1.8 8610ab G27 100 125 175 225 0.6 1 1.4 2.2 TEMPERATURE (°C) –55 INPUT VOLTAGE (V) 3.4 8610ab G28 2.8 2.4 –25 5 65 2.2 2.0 3.6 3.2 3.0 2.6 95 125 155 TEMPERATURE (°C) –55 –12.0PG THRESHOLD OFFSET FROM VREF (%) –11.5 –10.5 –10.0 –9.5 –7.0 –8.5 5 65 95 125 8610ab G26 –11.0 –8.0 –7.5 –9.0 –25 35 155 FB RISING FB FALLING Minimum Load to Full Frequency Burst Frequency Frequency Foldback INPUT VOLTAGE (V) LOAD CURRENT (mA) 15 25 40 8610ab G39 5 10 20 30 35 VOUT = 3.3V fSW = 700kHz PULSE-SKIPPING MODE FB VOLTAGE (V) SWITCHING FREQUENCY (kHz) 300 400 500 0.6 1 8610ab G22 200 100 0.2 0.4 0.8 600 700 800 VOUT = 3.3V VIN = 12V VSYNC = 0V RT = 60.4k LOAD CURRENT (mA) SWITCHING FREQUENCY (kHz) 400 500 600 800 8610ab G21 300 200 200 400 600 700100 300 500 100 800 VIN = 12V VOUT = 3.3V L = 4.7µH LT8610A LT8610AB 700

Rev. CFor more information www.analog.com Bias Pin Current Bias Pin Current INPUT VOLTAGE (V) BIAS PIN CURRENT (mA) 4.5 5.5 8610ab G29 3.5 2.5 15 25 3510 20 30 40 6.5 4.0 5.0 3.0 6.0 VBIAS = 5V VOUT = 5V ILOAD = 1A fSW = 700kHz SWITCHING FREQUENCY (MHz) BIAS PIN CURRENT (mA) 0.5 1 1.5 2 8610ab G30 2.5 VBIAS = 5V VOUT = 5V VIN = 12V ILOAD = 1A TYPICAL PERFORMANCE CHARACTERISTICS Switching Waveforms Switching Waveforms Switching Waveforms LT8610A/LT8610AB T ransient Response LT8610A/LT8610AB T ransient Response Start-Up Dropout Performance Start-Up Dropout Performance IL 1A/DIV VSW 5V/DIV 500ns/DIV 12VIN TO 5VOUT AT 1A 8610ab G31 IL 200mA/DIV VSW 5V/DIV 500µs/DIV 12VIN TO 5VOUT AT 10mA VSYNC = 0V (L T8610A) 8610ab G32 IL 1A/DIV VSW 10V/DIV 500ns/DIV 36VIN TO 5VOUT AT 1A 8610ab G33 IL 2A/DIV VOUT 200mV/DIV 50µs/DIV 1.5A TO 3.5A TRANSIENT 12VIN, 3.3VOUT COUT = 47µF 8610ab G34 IL 2A/DIV VOUT 200mV/DIV 50µs/DIV 30mA TO 2A TRANSIENT 12VIN, 3.3VOUT COUT = 47µF 8610ab G35 VIN 2V/DIV VOUT 2V/DIV 100ms/DIV 2.5/uni03A9 LOAD (2A IN REGULATION) 8610ab G37 VIN VOUT VIN 2V/DIV VOUT 2V/DIV 100ms/DIV 20/uni03A9 LOAD (250mA IN REGULATION) 8610ab G38 VIN VOUT

Rev. C For more information www.analog.com PIN FUNCTIONS SYNC ( Pin 1): External Clock Synchronization Input. Ground this pin for low ripple Burst Mode operation at low output loads. Tie to a clock source for synchronization to an external frequency. Apply a DC voltage of 3V or higher or tie to INTVCC for pulse-skipping mode. When in pulse- skipping mode, the IQ will increase to several hundred µA. Do not float this pin. TR/SS (Pin 2): Output T racking and Soft-Start Pin. This pin allows user control of output voltage ramp rate dur- ing start-up. A TR/SS voltage below 0.97 V forces the LT8610A/LT8610AB to regulate the FB pin to equal the TR/SS pin voltage. When TR/SS is above 0.97 V, the tracking function is disabled and the internal reference resumes control of the error amplifier. An internal 2.2μA pull-up current from INTVCC on this pin allows a capacitor to program output voltage slew rate. This pin is pulled to ground with an internal 230Ω MOSFET during shutdown and fault conditions; use a series resistor if driving from a low impedance output. This pin may be left floating if the tracking function is not needed. RT (Pin 3): A resistor is tied between RT and ground to set the switching frequency. EN/UV ( Pin 4): The LT8610A/LT8610AB is shut down when this pin is low and active when this pin is high. The hysteretic threshold voltage is 1.00V going up and 0.96V going down. Tie to VIN if the shutdown feature is not used. An external resistor divider from VIN can be used to program a VIN threshold below which the LT8610A/ LT8610AB will shut down. VIN (Pins 5, 6): The VIN pins supply current to the LT8610A/ LT8610AB internal circuitry and to the internal topside power switch. These pins must be tied together and be locally bypassed. Be sure to place the positive terminal of the input capacitor as close as possible to the VIN pins, and the negative capacitor terminal as close as possible to the GND pins. NC ( Pin 7): No Connect. This pin is not connected to internal circuitry. SW (Pins 9, 10, 11): The SW pins are the outputs of the internal power switches. Tie these pins together and con- nect them to the inductor and boost capacitor. This node should be kept small on the PCB for good performance. BST (Pin 12): This pin is used to provide a drive voltage, higher than the input voltage, to the topside power switch. Place a 0.1µF boost capacitor as close as possible to the IC. INTVCC ( Pin 13): Internal 3.4 V Regulator Bypass Pin. The internal power drivers and control circuits are pow- ered from this voltage. INTVCC maximum output cur- rent is 20mA. Do not load the INTVCC pin with external circuitry. INTVCC current will be supplied from BIAS if VBIAS > 3.1V, otherwise current will be drawn from VIN. Voltage on INTVCC will vary between 2.8V and 3.4V when VBIAS is between 3.0V and 3.6V. Decouple this pin to power ground with at least a 1μF low ESR ceramic capacitor placed close to the IC. BIAS (Pin 14): The internal regulator will draw current from BIAS instead of VIN when BIAS is tied to a voltage higher than 3.1V. For output voltages of 3.3V and above this pin should be tied to VOUT. If this pin is tied to a supply other than VOUT use a 1µF local bypass capacitor on this pin. PG (Pin 15): The PG pin is the open-drain output of an internal comparator. PG remains low until the FB pin is within ±9% of the final regulation voltage, and there are no fault conditions. PG is valid when VIN is above 3.4V, regardless of EN/UV pin state. FB ( Pin 16, LT8610A/LT8610AB Only): The LT8610A/ LT8610AB regulates the FB pin to 0.970V. Connect the feedback resistor divider tap to this pin. Also, connect a phase lead capacitor between FB and VOUT. Typically, this capacitor is 4.7pF to 10pF. VOUT (Pin 16, LT8610A-3.3/LT8610A-5/LT8610AB-3.3/ LT8610AB-5 Only): The LT8610A-3.3 and LT8610AB-3.3 regulate the VOUT pin to 3.3V. This pin connects to a 14.3MΩ internal feedback divider that programs the fixed output. The LT8610A-5 and LT8610AB-5 regulate the VOUT pin to 5V. This pin connects to a 12.5MΩ internal feedback divider that programs the fixed output. GND (Pin 8, Exposed Pad Pin 17): Ground. These pins are the return path of the internal bottom-side switch and must be tied together. Place the negative terminal of the input capacitor as close to the GND pin and exposed pad as possible. The exposed pad must be soldered to the PCB in order to lower the thermal resistance.

Rev. CFor more information www.analog.com BLOCK DIAGRAM ++– SLOPE COMP INTERNAL 0.97V REF OSCILLATOR 200kHz TO 2.2MHz BURST DETECT 3.4V REG CBST COUT VOUT 8610ab BD SW L BST 9-11 SWITCH LOGIC AND ANTI- SHOOT THROUGH ERROR AMP SHDN ±9% VC SHDN TSD INTVCC UVLO VIN UVLO L T8610A-3.3/L T8610A-5 L T8610AB-3.3/L T8610AB-5 ONL Y L T8610A/L T8610AB ONL Y SHDN TSD VIN UVLO EN/UV 1V + RT SYNC GND INTVCC BIAS 14 GND PG15 FB R1C1 OPT OPT RTCSS OPT VOUT TR/SS 2.2µA VINVIN CIN CVCC 5, 6 C1VOUT VOUT 16

Rev. C For more information www.analog.com OPERATION The LT8610A/LT8610AB is a monolithic, constant frequency, current mode step-down DC/DC converter. An oscillator, with frequency set using a resistor on the RT pin, turns on the internal top power switch at the beginning of each clock cycle. Current in the inductor then increases until the top switch current comparator trips and turns off the top power switch. The peak inductor current at which the top switch turns off is controlled by the voltage on the internal VC node. The error amplifier servos the VC node by comparing the voltage on the VFB pin with an internal 0.97V reference. When the load current increases it causes a reduction in the feedback voltage relative to the reference leading the error amplifier to raise the VC voltage until the average inductor current matches the new load current. When the top power switch turns off, the synchronous power switch turns on until the next clock cycle begins or inductor current falls to zero. If overload conditions result in more than 3.3A flowing through the bottom switch, the next clock cycle will be delayed until switch current returns to a safe level. If the EN/UV pin is low, the LT8610A/LT8610AB is shut down and draws 1µA from the input. When the EN/UV pin is above 1V, the switching regulator will become active. To optimize efficiency at light loads, the LT8610A/ LT8610AB operates in Burst Mode operation in light load situations. Between bursts, all circuitry associated with controlling the output switch is shut down, reducing the input supply current to 1.7μA. In a typical application, 2.5μA will be consumed from the input supply when regulating with no load. The SYNC pin is tied low to use Burst Mode operation and can be tied to a logic high to use pulse- skipping mode. If a clock is applied to the SYNC pin the part will synchronize to an external clock frequency and operate in pulse-skipping mode. While in pulse-skipping mode the oscillator operates continuously and positive SW transitions are aligned to the clock. During light loads, switch pulses are skipped to regulate the output and the quiescent current will be several hundred µA. To improve efficiency across all loads, supply current to internal circuitry can be sourced from the BIAS pin when biased at 3.3V or above. Else, the internal circuitry will draw current from VIN. The BIAS pin should be connected to VOUT if the LT8610A/LT8610AB output is programmed at 3.3V or above. Comparators monitoring the FB pin voltage (or VOUT pin voltages for fixed output versions) will pull the PG pin low if the output voltage varies more than ±9% (typical) from the set point, or if a fault condition is present. The oscillator reduces the LT8610A/LT8610AB’s operating frequency when the voltage at the FB pin (or VOUT pin for fixed output versions) is low. This frequency foldback helps to control the inductor current when the output voltage is lower than the programmed value which occurs during start-up or overcurrent conditions. When a clock is ap- plied to the SYNC pin or the SYNC pin is held DC high, the frequency foldback is disabled and the switching frequency will slow down only during overcurrent conditions. The LT8610AB differs from the LT8610A in that it has improved efficiency during Burst Mode operation. This comes with the trade-off of increased output voltage ripple, which can be proportionally decreased with an increase in output capacitance. The other trade-off is that the LT8610AB will not reach the full switching frequency programmed by the RT pin resistor until a higher load compared to the LT8610A.

as compared to the LT8610A (Figure 1a). plication, increasing inductor value can be a quick solution. Table 1. Output Voltage Ripple vs Output Capacitance for capacitor should be connected from VOUT to FB. = 1M and R2 = 412k, the feedback divider draws 2.3µA. Typical Performance Characteristics section. in Application Note AN-2582. a desired switching frequency is in Table 2.

Table 2. SW Frequency vs RT Value are lower efficiency and a smaller input voltage range. current to assure safe operation. a lower switching frequency than programmed by RT. dropped to achieve higher duty cycle. the use of a high speed peak-current mode architecture. (~0.21V) and L is the inductor value in μH.

Rev. C For more information www.analog.com APPLICATIONS INFORMATION where ∆IL is the inductor ripple current as calculated in Equation 9 and ILOAD(MAX) is the maximum output load for a given application. As a quick example, an application requiring 1A output should use an inductor with an RMS rating of greater than 1A and an ISAT of greater than 1.3A. During long duration overload or short-circuit conditons, the inductor RMS routing requirement is greater to avoid overheating of the inductor. To keep the efficiency high, the series resistance (DCR) should be less than 0.04Ω, and the core material should be intended for high frequency applications. The LT8610A/LT8610AB limits the peak switch current in order to protect the switches and the system from overload faults. The top switch current limit (ILIM) is at least 6A at low duty cycles and decreases linearly to 5A at DC = 0.8. The inductor value must then be sufficient to supply the desired maximum output current (IOUT(MAX)), which is a function of the switch current limit (ILIM) and the ripple current. IOUT(MAX) =ILIM – ΔIL (8) The peak-to-peak ripple current in the inductor can be calculated as follows: ΔIL = VOUT L •fSW

• 1– VOUT VIN(MAX) (9) where fSW is the switching frequency of the LT8610A/ LT8610AB, and L is the value of the inductor. Therefore, the maximum output current that the LT8610A/LT8610AB will deliver depends on the switch current limit, the induc- tor value, and the input and output voltages. The inductor value may have to be increased if the inductor ripple cur- rent does not allow sufficient maximum output current (IOUT(MAX)) given the switching frequency, and maximum input voltage used in the desired application. The optimum inductor for a given application may differ from the one indicated by this design guide. A larger value inductor provides a higher maximum load current and reduces the output voltage ripple. For applications requiring smaller load currents, the value of the inductor may be lower and the LT8610A/LT8610AB may operate with higher ripple current. This allows use of a physically smaller inductor, or one with a lower DCR resulting in higher efficiency. Be aware that low inductance may result in discontinuous mode operation, which further reduces maximum load current. Inductor value has a very strong effect on Burst Mode ef- ficiency. Larger value inductors allow more charge to be transferred to the output per pulse, which increases both efficiency and output voltage ripple. This dependence on inductance is stronger for the LT8610AB than it is for the LT8610A. If higher efficiency is needed in a Burst Mode ap- plication, increasing inductor value can be a quick solution. For more information about maximum output current and discontinuous operation, see Linear Technology’s Application Note 44. Finally, for duty cycles greater than 50% (VOUT/VIN > 0.5), a minimum inductance is required to avoid sub-harmonic oscillation. See Application Note 19. Input Capacitor Bypass the input of the LT8610A/LT8610AB circuit with a ceramic capacitor of X7R or X5R type placed as close as possible to the VIN and PGND pins. Y5V types have poor performance over temperature and applied voltage, and should not be used. A 4.7μF to 10μF ceramic capacitor is adequate to bypass the LT8610A/LT8610AB and will easily handle the ripple current. Note that larger input capacitance is required when a lower switching frequency is used. If the input power source has high impedance, or there is significant inductance due to long wires or cables, additional bulk capacitance may be necessary. This can be provided with a low performance electrolytic capacitor. Step-down regulators draw current from the input supply in pulses with very fast rise and fall times. The input capaci- tor is required to reduce the resulting voltage ripple at the LT8610A/LT8610AB and to force this very high frequency switching current into a tight local loop, minimizing EMI. A 4.7μF capacitor is capable of this task, but only if it is placed close to the LT8610A/LT8610AB (see the PCB Layout section). A second precaution regarding the ceramic input capacitor concerns the maximum input voltage rating of the LT8610A/LT8610AB. A ceramic input capacitor combined

Rev. CFor more information www.analog.com APPLICATIONS INFORMATION with trace or cable inductance forms a high quality (under damped) tank circuit. If the LT8610A/LT8610AB circuit is plugged into a live supply, the input voltage can ring to twice its nominal value, possibly exceeding the LT8610A/ LT8610AB’s voltage rating. This situation is easily avoided (see Linear Technology Application Note 88). Output Capacitor and Output Ripple The output capacitor has two essential functions. Along with the inductor, it filters the square wave generated by the LT8610A/LT8610AB to produce the DC output. In this role it determines the output ripple, thus low impedance at the switching frequency is important. The second function is to store energy in order to satisfy transient loads and stabilize the LT8610A/LT8610AB’s control loop. Ceramic capacitors have very low equivalent series resistance (ESR) and provide the best ripple performance. For good starting values, see the Typical Applications section. Use X5R or X7R types. This choice will provide low output ripple and good transient response. T ransient performance can be improved with a higher value output capacitor and the addition of a feedforward capacitor placed between VOUT and FB. Increasing the output capacitance will also decrease the output voltage ripple. A lower value of output capacitor can be used to save space and cost but transient performance will suffer and may cause loop instability. See the Typical Applications in this data sheet for suggested capacitor values. When choosing a capacitor, special attention should be given to the data sheet to calculate the effective capacitance under the relevant operating conditions of voltage bias and temperature. A physically larger capacitor or one with a higher voltage rating may be required. Ceramic Capacitors Ceramic capacitors are small, robust and have very low ESR. However, ceramic capacitors can cause problems when used with the LT8610A/LT8610AB due to their piezoelectric nature. When in Burst Mode operation, the LT8610A/LT8610AB’s switching frequency depends on the load current, and at very light loads the LT8610A/ LT8610AB can excite the ceramic capacitor at audio fre- quencies, generating audible noise. Since the LT8610A/ LT8610AB operates at a lower current limit during Burst Mode operation, the noise is typically very quiet to a ca- sual ear. If this is unacceptable, use a high performance tantalum or electrolytic capacitor at the output. Low noise ceramic capacitors are also available. A final precaution regarding ceramic capacitors concerns the maximum input voltage rating of the LT8610A/LT8610AB. As previously mentioned, a ceramic input capacitor combined with trace or cable inductance forms a high quality (un- derdamped) tank circuit. If the LT8610A/LT8610AB circuit is plugged into a live supply, the input voltage can ring to twice its nominal value, possibly exceeding the LT8610A/ LT8610AB’s rating. This situation is easily avoided (see Linear Technology Application Note 88). Enable Pin The LT8610A/LT8610AB is in shutdown when the EN pin is low and active when the pin is high. The rising threshold of the EN comparator is 1.0V, with 40mV of hysteresis. The EN pin can be tied to VIN if the shutdown feature is not used, or tied to a logic level if shutdown control is required. Adding a resistor divider from VIN to EN programs the LT8610A/LT8610AB to regulate the output only when VIN is above a desired voltage (see the Block Diagram). Typi- cally, this threshold, VIN(EN), is used in situations where the input supply is current limited, or has a relatively high source resistance. A switching regulator draws constant power from the source, so source current increases as source voltage drops. This looks like a negative resistance load to the source and can cause the source to current limit or latch low under low source voltage conditions. The VIN(EN) threshold prevents the regulator from operating at source voltages where the problems might occur. This threshold can be adjusted by setting the values R3 and R4 such that they satisfy the following equation: VIN(EN) = R3 R4 +1⎛ ⎝⎜ ⎞ ⎠⎟•1.0V (10) where the LT8610A/LT8610AB will remain off until VIN is above VIN(EN). Due to the comparator’s hysteresis, switch- ing will not stop until the input falls slightly below VIN(EN).

Rev. C For more information www.analog.com APPLICATIONS INFORMATION When operating in Burst Mode operation for light load currents, the current through the VIN(EN) resistor network can easily be greater than the supply current consumed by the LT8610A/LT8610AB. Therefore, the VIN(EN) resis- tors should be large to minimize their effect on efficiency at low loads. INTVCC Regulator An internal low dropout (LDO) regulator produces the 3.4V supply from VIN that powers the drivers and the internal bias circuitry. The INTVCC can supply enough current for the LT8610A/LT8610AB’s circuitry and must be bypassed to ground with a minimum of 1μF ceramic capacitor. Good bypassing is necessary to supply the high transient currents required by the power MOSFET gate drivers. To improve efficiency the internal LDO can also draw current from the BIAS pin when the BIAS pin is at 3.1V or higher. Typically the BIAS pin can be tied to the output of the LT8610A/ LT8610AB, or can be tied to an external supply of 3.3V or above. If BIAS is connected to a supply other than VOUT, be sure to bypass with a local ceramic capacitor. If the BIAS pin is below 3.0V, the internal LDO will consume current from VIN. Applications with high input voltage and high switching frequency where the internal LDO pulls current from VIN will increase die temperature because of the higher power dissipation across the LDO. Do not connect an external load to the INTVCC pin. Output Voltage T racking and Soft-Start The LT8610A/LT8610AB allows the user to program its out- put voltage ramp rate by means of the TR/SS pin. An internal 2.2μA pulls up the TR/SS pin to INTVCC. Putting an external capacitor on TR/SS enables soft starting the output to prevent current surge on the input supply. During the soft- start ramp the output voltage will proportionally track the TR/SS pin voltage. For output tracking applications, TR/SS can be externally driven by another voltage source. From 0V to 0.97V, the TR/SS voltage will override the internal 0.97V reference input to the error amplifier, thus regulating the FB pin voltage to that of TR/SS pin. In the fixed output voltage options the output voltage will track the TR/SS pin voltage based on a factor set by the internal feedback resistor divider. The 3.3V output options will track to a voltage 3.4 times that of the TR/SS pin, while the 5V output options will track to a voltage 5.15 times that of the TR/SS pin. When TR/SS is above 0.97V, tracking is disabled and the feedback voltage will regulate to the internal reference voltage. The TR/SS pin may be left floating if the function is not needed. An active pull-down circuit is connected to the TR/SS pin which will discharge the external soft-start capacitor in the case of fault conditions and restart the ramp when the faults are cleared. Fault conditions that clear the soft-start capacitor are the EN/UV pin transitioning low, VIN voltage falling too low, or thermal shutdown. Output Power Good When the LT8610A/LT8610AB’s output voltage is within the ±9% window of the regulation point, which is a VFB voltage in the range of 0.883V to 1.057V (typical), the output voltage is considered good and the open-drain PG pin goes high impedance and is typically pulled high with an external resistor. Otherwise, the internal pull-down device will pull the PG pin low. To prevent glitching both the upper and lower thresholds include 1.3% of hysteresis. This ±9% power good window around the regulation point is the same for the fixed output options, which for the 3.3V output version corresponds to a 3.003V to 3.597V range (typical) and for the 5V output version corresponds to a 4.55V to 5.45V range (typical). The PG pin is also actively pulled low during several fault conditions: EN/UV pin is below 1V, INTVCC has fallen too low, VIN is too low, or thermal shutdown. Synchronization To select low ripple Burst Mode operation, tie the SYNC pin below 0.4V (this can be ground or a logic low output). To synchronize the LT8610A/LT8610AB oscillator to an external frequency connect a square wave (with 20% to 80% duty cycle) to the SYNC pin. The square wave am- plitude should have valleys that are below 0.4V and peaks above 2.4V (up to 6V). The LT8610A/LT8610AB will not enter Burst Mode opera- tion at low output loads while synchronized to an external clock, but instead will pulse skip to maintain regulation. The LT8610A/LT8610AB may be synchronized over a 200kHz to 2.2MHz range. The RT resistor should be chosen to set

Figure 3. Reverse VIN Protection by the inductor size, input voltage, and output voltage. sufficient for all synchronization frequencies. is reached at lower output load than in Burst Mode operation. pin is tied high either to a logic output or to the INTVCC pin. The LT8610A/LT8610AB will tolerate a shorted output. inductor current falls to safe levels. slow switching if the inductor current exceeds safe levels. against a shorted or reversed input.

Rev. CFor more information www.analog.com TYPICAL APPLICATIONS BSTVIN EN/UV SYNC INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS 8610ab TA02 PG FB 0.1µF VOUT 3.5A 4.7µF VIN 5.5V TO 42V 1µF 10nF 4.7pF 2.2µH 243k fSW = 2MHz L: XAL 5030 18.2k 47µF* 1210 X7R POWER GOOD 100k 5V 2MHz Step-Down Converter 5V Step-Down Converter *Consider doubling output capacitance for LT8610AB if application requires low output voltage ripple in Burst Mode operation. 12V Step-Down Converter L: IHLP-2525CZ-01 BSTVIN EN/UV SYNC INTVCC TR/SS RT SWL T8610A-5 GND BIAS 8610ab TA03 VOUT 0.1µF VOUT 12V 3.5A 4.7µF VIN 3.8V TO 42V 1µF 10nF 10µH fSW = 400kHz 110k 100µF 1210 X5R PG POWER GOOD 100k BSTVIN EN/UV SYNC INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS 8610ab TA09 PG FB 0.1µF VOUT 12V 3.5A 4.7µF VIN 12.5V TO 42V 1µF 10nF 10pF 10µH 88.7k fSW = 1MHz 41.2k 47µF* 1210 X7R POWER GOOD 100k L: IHLP-2525CZ-01

Rev. C For more information www.analog.com TYPICAL APPLICATIONS 1.8V 2MHz Step-Down Converter *Consider doubling output capacitance for LT8610AB if application requires low output voltage ripple in Burst Mode operation. BSTVIN EN/UV SYNC PG INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS 8610ab TA06 FB 0.1µF VOUT 1.8V 3.5A 4.7µF VIN 3.4V TO 15V (42V TRANSIENT) 1µF 10nF 4.7pF 1µH 866k fSW = 2MHz 18.2k 100µF* 1210 X5R L: IHLP-2020BZ-01 3.3V 2MHz Step-Down Converter BSTVIN EN/UV SYNC PG INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS 8610ab TA04 FB 0.1µF VOUT 3.3V 3.5A 4.7µF VIN 3.8V TO 27V (42V TRANSIENT) 1µF 10nF 4.7pF 2.2µH 412k fSW = 2MHz 18.2k 47µF* 1210 X7R L: XAL 5030 1.8V Step-Down Converter BSTVIN EN/UV SYNC PG INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS 8610ab TA07 FB 0.1µF VOUT 1.8V 3.5A 4.7µF VIN 3.4V TO 42V 1µF 10nF 4.7pF 4.7µH 866k fSW = 400kHz 110k 47µF* 1210 X7R L: IHLP-2020BZ-01

Rev. CFor more information www.analog.com TYPICAL APPLICATIONS 3.3V Step-Down Converter Ultralow EMI 5V 2.5A Step-Down Converter L: IHLP-2525BD-01 BSTVIN EN/UV PG SYNC INTVCC TR/SS RT SWL T8610A-3.3 GND BIAS 8610ab TA05 VOUT 0.1µF VOUT 3.3V 3.5A 4.7µF VIN 3.8V TO 42V 1µF 10nF 8.2µH fSW = 400kHz 110k 100µF 1210 X5R BSTVIN EN/UV PG SYNC INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS 8610ab TA11 FB 0.1µF VOUT 3.5A 4.7µF VIN 5.5V TO 42V 1µF 10nF 10pF 4.7µH 4.7µH FB1 BEAD 243k fSW = 800kHz 52.3k 4.7µF4.7µF 47µF* 1210 X7R FB1: TDK MPZ2012S101A L: IHLP-2020BZ-01 *Consider doubling output capacitance for LT8610AB if application requires low output voltage ripple in Burst Mode operation.

Rev. C For more information www.analog.com PACKAGE DESCRIPTION MSOP (MSE16) 0213 REV F 0.53 ±0.152 (.021 ±.006) SEATING PLANE 0.18 (.007) 1.10 (.043) MAX 0.17 –/uni00A00.27 (.007 – .011) TYP 0.86 (.034) REF 0.50 (.0197) BSC 16151413121110 1 2 3 4 5 6 7 8 1 8 NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL NOT EXCEED 0.254mm (.010") PER SIDE. 0.254 (.010) 0° – 6° TYP DETAIL “A” DETAIL “A” GAUGE PLANE 5.10 (.201) MIN 3.20 – 3.45 (.126 – .136) 0.889 ±0.127 (.035 ±.005) RECOMMENDED SOLDER PAD LAYOUT 0.305 ±0.038 (.0120 ±.0015) TYP 0.50 (.0197) BSC BOTTOM VIEW OF EXPOSED PAD OPTION 2.845 ±0.102 (.112 ±.004) 2.845 ±0.102 (.112 ±.004) 4.039 ±0.102 (.159 ±.004) (NOTE 3) 1.651 ±0.102 (.065 ±.004) 1.651 ±0.102 (.065 ±.004) 0.1016 ±0.0508 (.004 ±.002) 3.00 ±0.102 (.118 ±.004) (NOTE 4) 0.280 ±0.076 (.011 ±.003) REF 4.90 ±0.152 (.193 ±.006) DETAIL “B” DETAIL “B” CORNER TAIL IS PART OF THE LEADFRAME FEATURE. FOR REFERENCE ONL Y NO MEASUREMENT PURPOSE

0.12 REF

0.35 REF 16-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1667 Rev F)

Rev. CFor more information www.analog.com Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

REVISION HISTORY

REV DATE DESCRIPTION PAGE NUMBER A 08/14 Added fixed output options. Clarified Applications Information. 1 - 4, 10, 12, 13 14, 18 B 02/21 Added AECQ-100 statement. Added #W models. C 10/24 Added High VOUT Considerations Section to the Applications Information. 14

Rev. C For more information www.analog.com  ANALOG DEVICES, INC. 2013-2024 www.analog.com RELATED PARTS TYPICAL APPLICATION 3.3V and 1.8V with Ratio T racking Ultralow IQ 2.5V, 3.3V Step-Down with LDO BSTVIN EN/UV SYNC PG INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS FB 0.1µF VOUT1 3.3V 3.5A 4.7µF VIN 3.8V TO 42V 1µF 10nF 4.7pF 5.6µH 232k 97.6k fSW = 500kHz 88.7k BSTVIN EN/UV SYNC PG INTVCC TR/SS RT SWL T8610A/ L T8610AB GND BIAS 8610ab TA08 FB 0.1µF VOUT2 1.8V 3.5A 4.7µF 1µF 4.7pF 3.3µH 80.6k 24.3k 93.1k fSW = 500kHz 88.7k 10k 100µF* 1210 X5R 47µF* 1210 X7R L: IHLP-2020CZ-01, 5.6µH L: IHLP-2020CZ-01, 3.3µH BSTVIN EN/UV SYNC PG INTVCC TR/SS RT SW L T8610AB-3.3 GND BIAS 8610ab TA10 VOUT 0.1µF VOUT1 3.3V 3.5A 4.7µF VIN 3.8V TO 27V 1µF 10nF 2.2µH 2.2µF VOUT2 2.5V 20mA fSW = 2MHz 18.2k 47µF 1210 X7R IN L T3008-2.5 SHDN OUT SENSE L: IHLP-2020BZ-01 PART NUMBER DESCRIPTION COMMENTS LT8610 42V, 2.5A, 96% Efficiency, 2.2MHz Synchronous Micropower Step-Down DC/DC Converter with IQ = 2.5µA VIN: 3.4V to 42V, VOUT(MIN) = 0.97V, IQ = 2.5µA, ISD < 1µA, MSOP-16E Package LT8614 42V, 2.5A with 4A, 96% Efficiency, 2.2MHz Synchronous Micropower Step-Down DC/DC Converter with IQ = 2.5µA VIN: 3.4V to 42V, VOUT(MIN) = 0.97V, IQ = 2.5µA, ISD < 1µA, 3mm × 6mm QFN-28 Package LT8611 42V, 2.5A, 96% Efficiency, 2.2MHz Synchronous Micropower Step-Down DC/DC Converter with IQ = 2.5µA and Input/Output Current Limit/Monitor VIN: 3.4V to 42V, VOUT(MIN) = 0.97V, IQ = 2.5µA, ISD < 1µA, 3mm × 5mm QFN-24 Package LT3690 36V with 60V T ransient Protection, 4A, 92% Efficiency, 1.5MHz Synchronous Micropower Step-Down DC/DC Converter with IQ = 70µA VIN: 3.9V to 36V, VOUT(MIN) = 0.985V, IQ = 70µA, ISD < 1µA, 4mm × 6mm QFN-26 Package LT3971 38V, 1.2A, 2.2MHz High Efficiency Micropower Step-Down DC/DC Converter with IQ = 2.8µA VIN: 4.2V to 38V, VOUT(MIN) = 1.21V, IQ = 2.8µA, ISD < 1µA, 3mm × 3mm DFN-10 and MSOP-10E Packages LT3970 40V, 350mA, 2.2MHz High Efficiency Micropower Step-Down DC/DC Converter with IQ = 2.5µA VIN: 4.2V to 40V, VOUT(MIN) = 1.21V, IQ = 2.5µA, ISD < 1µA, 3mm × 2mm DFN-10 and MSOP-10 Packages LT3990 62V, 350mA, 2.2MHz High Efficiency MicroPower Step-Down DC/DC Converter with IQ = 2.5µA VIN: 4.2V to 62V, VOUT(MIN) = 1.21V, IQ = 2.5µA, ISD < 1µA, 3mm × 3mm DFN-10 and MSOP-6E Packages LT3480 36V with T ransient Protection to 60V, 2A (IOUT), 2.4MHz, High Efficiency Step-Down DC/DC Converter with Burst Mode Operation VIN: 3.6V to 36V, T ransient to 60V, VOUT(MIN) = 0.78V, IQ = 70µA, ISD < 1µA, 3mm × 3mm DFN-10 and MSOP-10E Packages LT3980 58V with T ransient Protection to 80V, 2A (IOUT), 2.4MHz, High Efficiency Step-Down DC/DC Converter with Burst Mode Operation VIN: 3.6V to 58V, T ransient to 80V, VOUT(MIN) = 0.78V, IQ = 85µA, ISD < 1µA, 3mm × 4mm DFN-16 and MSOP-16E Packages *Consider doubling output capacitance for LT8610AB if application requires low output voltage ripple in Burst Mode operation.