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LINEAR TECHNOLOGY LT3693 Data Sheet manual instructions

Summary

This high-efficiency, adjustable buck switching regulator (DC/DC converter) from Linear Technology is designed for robust voltage conversion across demanding applications. The LT3693 features a wide input range of 3.6V to 36V and an adjustable frequency up to 2.4MHz, delivering up to 3.5A output while maintaining high efficiency. Ideal for engineers developing products that require reliable power management, including automotive systems, industrial supplies, portable electronics, and distributed voltage regulation circuits. The accompanying manual details its advanced features like soft-start capability and Power Good flagging.

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LT3693

36V, 3.5A, 2.4MHz

Step-Down Switching Regulator

FEATURES DESCRIPTIO

■ Wide Input Range: 3.6V to 36V The LT®3693 is an adjustable frequency (200k Hz to ■ 3.5A Maximum Output Current 2.4MHz) monolithic buck switching regulator that accepts ■ Adjustable Switching Frequency: 200k Hz to 2.4MHz input voltages up to 36V. A high effi ciency 95m switch ■ Low Shutdown Current: IQ < 1μA is included on the die along with a boost Schottky diode ■ Integrated Boost Diode and the necessary oscillator, control, and logic circuitry. ■ Synchronizable Between 250k Hz to 2MHz Current mode topology is used for fast transient response ■ Power Good Flag and good loop stability. Shutdown reduces input supply ■ Saturating Switch Design: 95m On-Resistance current to less than 1μA while a resistor and capacitor on ■ 0.790V Feedback Reference Voltage the RUN/SS pin provide a controlled output voltage ramp ■ Output Voltage: 0.79V to 30V (soft-start). A power good fl ag signals when VOUT reaches ■ Thermal Protection 91% of the programmed output voltage. The LT3693 is ■ Soft-Start Capability available in 10-Pin MSOP and 3mm × 3mm DFN packages ■ Small 10-Pin Thermally Enhanced MSOP and with exposed pads for low thermal resistance. (3mm × 3mm) DFN Packages

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.

APPLICATIO

EF FI CI EN CY

■ Automotive Battery Regulation

■ Power for Portable Products

■ Distributed Supply Regulation

■ Industrial Supplies

■ Wall Transformer Regulation

TYPICAL APPLICATIO

5V Step-Down Converter

Effi ciency

6.3V TO 36V

VIN = 12V

VIN BD

OFF ON RUN/SS BOOST

VIN = 34V

VIN = 24V

VC LT3693 SW

536k VOUT = 5V

63.4k SYNC FB L = 4.7μH

f = 600k Hz

OUTPUT CURRENT (A)

3693 TA01a 3693 G01

Page Summary Contents For LINEAR TECHNOLOGY LT3693 Data Sheet manual instructions

Page 1 LT3693 36V, 3.5A, 2.4MHz Step-Down Switching Regulator FEATURES DESCRIPTIO ■ Wide Input Range: 3.6V to 36V The LT®3693 is an adjustable frequency (200k Hz to ■ 3.5A Maximum Output Current 2.4MHz) mono...
Page 2 LT3693 ABSOLUTE AXI RATI GS (Note 1) VIN, RUN/SS Voltage .................................................36V Operating Junction Temperature Range (Note 2) BOOST Pin Voltage .............................
Page 3 LT3693 ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 10V, VRUN/SS = 10V, VBOOST ...
Page 4 TOTAL POW ER LOSS (W SW IT CH UR RE NT IM IT (A LO AD UR RE NT (A EF FI CI EN CY LT3693 TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C unless otherwise noted. Effi ciency Effi ciency Effi ciency VIN = ...
Page 5 FE ED BA CK OL TA GE (m V) BO OS DI OD (V IN IM UM IT CH TI (n s) LT3693 TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C unless otherwise noted. Feedback Voltage Switching Frequency Frequency Foldback 1...
Page 6 IN PU VO LT AG (V LT3693 TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C unless otherwise noted. Minimum Input Voltage VC Voltages Power Good Threshold 2.50 CURRENT LIMIT CLAMP SWITCHING THRESHOLD OL TA...
Page 7 LT3693 PI FU CTIO BD (Pin 1): This pin connects to the anode of the boost SYNC (Pin 6): This is the external clock synchronization Schottky diode. BD also supplies current to the internal input. Groun...
Page 8 LT3693 OPERATION The LT3693 is a constant frequency, current mode step- effi ciency. The RUN/SS pin is used to place the LT3693 down regulator. An oscillator, with frequency set by RT, in shutdown, di...
Page 9 LT3693 APPLICATIONS INFORMATION FB Resistor Network where VIN is the typical input voltage, VOUT is the output voltage, VD is the catch diode drop (~0.5V) and VSW is the The output voltage is programm...
Page 10 LT3693 APPLICATIONS INFORMATION operating input voltage. Conversely, a lower switching ripple current. The LT3693’s switch current limit (ILIM) is frequency will be necessary to achieve safe operation...
Page 11 LT3693 APPLICATIONS INFORMATION Of course, such a simple design guide will not always re- ceramic input capacitor concerns the maximum input sult in the optimum inductor for your application. A larger...
Page 12 LT3693 APPLICATIONS INFORMATION Table 2. Capacitor Vendors VENDOR PHONE URL PART SERIES COMMANDS Panasonic (714) 373-7366 www.panasonic.com Ceramic, Polymer, EEF Series Tantalum Kemet (864) 963-6300 w...
Page 13 LT3693 APPLICATIONS INFORMATION Frequency Compensation well as long as the value of the inductor is not too high and the loop crossover frequency is much lower than the The LT3693 uses current mode co...
Page 14 LT3693 APPLICATIONS INFORMATION VOUT is marginally adequate to support the boosted drive stage BD while using the internal boost diode. For reliable BOOST pin BOOST operation with 2.5V outputs use a g...
Page 15 LT3693 APPLICATIONS INFORMATION The minimum operating voltage of an LT3693 application is limited by the minimum input voltage (3.6V) and by the IL RUN 1A/DIV maximum duty cycle as outlined in a previ...
Page 16 LT3693 APPLICATIONS INFORMATION Shorted and Reversed Input Protection PCB Layout If the inductor is chosen so that it won’t saturate exces- For proper operation and minimum EMI, care must be sively, a...
Page 17 LT3693 APPLICATIONS INFORMATION Hot Plugging Safely energized supply, the input network should be designed to prevent this overshoot. Figure 9 shows the waveforms The small size, robustness and low im...
Page 18 LT3693 APPLICATIONS INFORMATION High Temperature Considerations Power dissipation within the LT3693 can be estimated by calculating the total power loss from an effi ciency measure- The PCB must provi...
Page 19 LT3693 TYPICAL APPLICATIONS 3.3V Step-Down Converter 4.6V TO 36V VIN BD ON OFF RUN/SS BOOST VC SW LT3693 63.4k SYNC f = 600k Hz 3693 TA03 D: ON SEMI MBRA340 L: NEC MPLC0730L3R3 2.5V Step-Down Converte...
Page 20 LT3693 TYPICAL APPLICATIONS 5V, 2MHz Step-Down Converter VIN VOUT 8.6V TO 22V 5V TRANSIENT TO 36V 2.5A VIN BD ON OFF RUN/SS BOOST VC SW LT3693 SYNC FB f = 2MHz 3693 TA05 D: ON SEMI MBRA340 L: NEC MPLC...
Page 21 LT3693 TYPICAL APPLICATIONS 1.8V Step-Down Converter VIN 1.8V 3.6V TO 27V 3.5A VIN BD ON OFF RUN/SS BOOST VC SW LT3693 SYNC FB f = 500k Hz 3693 TA08 D: ON SEMI MBRA340 L: NEC MPLC0730L3R3
Page 22 LT3693 PACKAGE DESCRIPTION DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) (2 SIDES)2.15 ±0.05 PACKAGE OUTLINE 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AN...
Page 23 LT3693 PACKAGE DESCRIPTION MSE Package 10-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1664 Rev B) BOTTOM VIEW OF EXPOSED PAD OPTION TYP BSC (NOTE 3) RECOMMENDED SOLDER PAD LAYOUT (NO...
Page 24 LT3693 TYPICAL APPLICATIO 1.2V Step-Down Converter VIN 1.2V 3.6V TO 27V 3.5A VIN BD ON OFF RUN/SS BOOST VC SW 4.7F LT3693 78.7k FB f = 500k Hz 3693 TA09 D: ON SEMI MBRA340 L: NEC MPLC0730L3R3 RELATED...

Manual Details

Brand Linear
Pages 24
File Size 316.29 KB
Published May 29, 2026
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Frequently Asked Questions

What is the input voltage range for the LT3693?

The device accepts a wide input range of 3.6V to 36V.

What are the operating temperature limits?

For the LT3693E and LT3693I, the operating junction temperature range is -40°C to 125°C.

Does it have soft-start capability?

Soft-Start capability is available in both the 10-Pin MSOP and 3mm × 3mm DFN packages.

What is the maximum output current?

The LT3693 supports a maximum output current of 3.5A.