Analog Devices LT3686

Overview

Topology	Buck Converter
Input voltage	3.6-37 V
Switching frequency	300-2500 kHz
Output 1	1.2 A
IC revision	C

Description

The LT®3686 is a current mode PWM step-down DC/DC converter with an internal 1.2A power switch, packaged in 10-lead 3mm × 3mm DFN. The wide input range of 3.6V to 37V makes the LT3686 suitable for regulating power from a wide variety of sources, including 24V industrial supplies and automotive batteries. Its high maximum frequency allows the use of tiny inductors and capacitors, resulting in a very small solution. Operating frequency above the AM band avoids interfering with radio reception, making the LT3686 particularly suitable for automotive applications.

Cycle-by-cycle current limit and DA current sense provide protection against fault conditions. Soft-start and frequency foldback eliminate input current surge during start-up. An optional internal regulated active load at the output via the BD pin keeps the LT3686 at full switching frequency at light loads, resulting in low, predictable output ripple above the audio and AM bands. Internal compensation and an internal boost diode reduce external component count.

Features

Wide Input Range:Operation from 3.6V to 37VOvervoltage Lockout Protects Circuit Through 55V Transients
Low Minimum On-Time:Converts 16VIN to 3.3VOUT at 2MHz
1.2A Output Current
Adjustable Frequency: 300kHz to 2.5MHz
Constant Switching Frequency at Light Loads
Tracking and Soft-Start
Precision UVLO
Short-Circuit Robust
IQ in Shutdown <1μA
Internally Compensated
10-Lead 3mm × 3mm DFN Package

Remarks

Inductor Value Are Given in Page no-13

Typical applications

Battery-Powered Equipment
Distributed Supply Regulation
Automotive Systems
Wall Transformer Regulation

More information

Products

Order Code	Datasheet	Simulation	Downloads	Status	Product series	L(µH)	I_R(A)	I_SAT(A)	R_{DC max.}(Ω)	f_res(MHz)	SamplesAvailability & Sample
744774022	SPECWE-PD2 SMT Power Inductor, 2.2 µH, 4.6 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance2.2 µH	Rated Current4.6 A	Saturation Current8.2 A	DC Resistance0.041 Ω	Self Resonant Frequency54 MHz	–Check availability
744774027	SPECWE-PD2 SMT Power Inductor, 2.7 µH, 4 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance2.7 µH	Rated Current4 A	Saturation Current8 A	DC Resistance0.045 Ω	Self Resonant Frequency50 MHz	–Check availability
744774033	SPECWE-PD2 SMT Power Inductor, 3.3 µH, 4 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance3.3 µH	Rated Current4 A	Saturation Current7.5 A	DC Resistance0.06 Ω	Self Resonant Frequency43 MHz	–Check availability
744774047	SPECWE-PD2 SMT Power Inductor, 4.7 µH, 3 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance4.7 µH	Rated Current3 A	Saturation Current5.5 A	DC Resistance0.071 Ω	Self Resonant Frequency33 MHz	–Check availability
744774068	SPECWE-PD2 SMT Power Inductor, 6.8 µH, 2.4 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance6.8 µH	Rated Current2.4 A	Saturation Current5 A	DC Resistance0.082 Ω	Self Resonant Frequency28 MHz	–Check availability
74477410	SPECWE-PD2 SMT Power Inductor, 10 µH, 2.2 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance10 µH	Rated Current2.2 A	Saturation Current2.5 A	DC Resistance0.1 Ω	Self Resonant Frequency26 MHz	–Check availability
744774112	SPECWE-PD2 SMT Power Inductor, 12 µH, 2 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance12 µH	Rated Current2 A	Saturation Current1.94 A	DC Resistance0.11 Ω	Self Resonant Frequency24 MHz	–Check availability
744774115	SPECWE-PD2 SMT Power Inductor, 15 µH, 1.53 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance15 µH	Rated Current1.53 A	Saturation Current1.9 A	DC Resistance0.14 Ω	Self Resonant Frequency23 MHz	–Check availability
744774118	SPECWE-PD2 SMT Power Inductor, 18 µH, 1.45 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance18 µH	Rated Current1.45 A	Saturation Current1.69 A	DC Resistance0.15 Ω	Self Resonant Frequency21 MHz	–Check availability
744774122	SPECWE-PD2 SMT Power Inductor, 22 µH, 1.28 A	Simulation	Availability –	Downloads9 files EDA models: Components ZIP ALT WE-PD2 (rev25b).IntLib \| 439 KB CDS Cadence_WE-PD2 (rev23a).zip \| 3.2 MB EAG Eagle_WE-PD2 (rev25a).lbr \| 98.8 KB KIC KiCad_WE-PD2 (rev26b).zip \| 371.6 KB ZUK CadStar_WE-PD2 (rev19b).zip \| 15.1 KB CAD files ZIP IGS WE-PD2_5848 (rev1).igs \| 1.6 MB STP WE-PD2_5848 (rev1).stp \| 608.9 KB Electric models ZIP PSP PSpice_WE-PD2 (rev25a).zip \| 19.1 KB SCS Spectre_WE-PD2 (rev24a).mod \| 22.1 KB Download all 9 files as zip archive ZIP	Status Activei\| Production is active. Expected lifetime: >10 years.	Product seriesWE-PD2 SMT Power Inductor	Inductance22 µH	Rated Current1.28 A	Saturation Current1.53 A	DC Resistance0.18 Ω	Self Resonant Frequency16 MHz	–Check availability

IC manufacturers (103)

37V/1.2A Step-Down Regulator in 3mm × 3mm DFN