Datasheet LT3686A (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 37V/1.2A Step-Down Regulator in 3mm × 3mm DFN and MSE |
| Pages / Page | 30 / 1 — FeAtures. Description. Wide Input Range:. Operation from 3.6V to 37V. … |
| File Format / Size | PDF / 522 Kb |
| Document Language | English |
FeAtures. Description. Wide Input Range:. Operation from 3.6V to 37V. Overvoltage Lockout Protects Circuit Through
Model Line for this Datasheet
Text Version of Document
LT3686A 37V/1.2A Step-Down Regulator in 3mm × 3mm DFN and MSE
FeAtures Description
■
Wide Input Range:
The LT®3686A is a current mode PWM step-down DC/DC
Operation from 3.6V to 37V
converter with an internal power switch. The wide input
Overvoltage Lockout Protects Circuit Through
range of 3.6V to 37V makes the LT3686A suitable for
60V Transients
regulating power from a wide variety of sources, including ■
Low Minimum On-Time:
24V industrial supplies and automotive batteries. Its high
Converts 16VIN to 3.3VOUT at 2MHz
maximum frequency al ows the use of tiny inductors and ■
1.2A Output Current
capacitors, resulting in a very small solution. Operating ■
Adjustable Frequency: 300kHz to 2.5MHz
frequency above the AM band avoids interfering with radio ■
Constant Switching Frequency at Light Loads
reception, making the LT3686A particularly suitable for ■
Can Be Synchronized to External Clock
automotive applications. ■ Tracking and Soft-Start Cycle-by-cycle current limit, thermal shutdown and DA ■ Precision UVLO current sense provide protection against fault conditions. ■ Short-Circuit Robust Soft-start and frequency foldback eliminate input current ■ IQ in Shutdown <1µA surge during start-up. An optional internal regulated active ■ Internal y Compensated load at the output via the BD pin keeps the LT3686A at ■ Thermal y Enhanced MSOP and 3mm × 3mm DFN full switching frequency at light loads, resulting in low, Packages predictable output ripple above the audio and AM bands.
ApplicAtions
Internal compensation and an internal boost diode reduce external component count. ■ Automotive Systems The LT3686A offers external synchronization capability, ■ Battery-Powered Equipment whereas the LT3686 does not. ■ Wal Transformer Regulation L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks ■ Distributed Supply Regulation of Linear Technology Corporation. All other trademarks are the property of their respective owners.
typicAl ApplicAtion 3.3V Step-Down Converter 12VIN Efficiency (2MHz)
90 VIN V 6V TO 37V IN BD 80 3.3V 2.2µF OUT EN/UVLO BOOST 0.22µF 70 5V 2MHz LT3686A OUT 6.8µH 60 SYNC/MODE SW VOUT 3.3V 50 MBRM140 SS 1.2A 40 DA 10nF RT 31.6k EFFICIENCY (%) FB 30 GND 20 31.6k 10k 22µF 10 3686A TA01a 0 0 200 400 600 800 1000 1200 (VIN 6V TO 16V AT 2MHz) LOAD CURRENT (mA) 3686A TA01b 3686afa 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
FeAtures Description
■
Wide Input Range:
The LT®3686A is a current mode PWM step-down DC/DC
Operation from 3.6V to 37V
converter with an internal power switch. The wide input
Overvoltage Lockout Protects Circuit Through
range of 3.6V to 37V makes the LT3686A suitable for
60V Transients
regulating power from a wide variety of sources, including ■
Low Minimum On-Time:
24V industrial supplies and automotive batteries. Its high
Converts 16VIN to 3.3VOUT at 2MHz
maximum frequency al ows the use of tiny inductors and ■
1.2A Output Current
capacitors, resulting in a very small solution. Operating ■
Adjustable Frequency: 300kHz to 2.5MHz
frequency above the AM band avoids interfering with radio ■
Constant Switching Frequency at Light Loads
reception, making the LT3686A particularly suitable for ■
Can Be Synchronized to External Clock
automotive applications. ■ Tracking and Soft-Start Cycle-by-cycle current limit, thermal shutdown and DA ■ Precision UVLO current sense provide protection against fault conditions. ■ Short-Circuit Robust Soft-start and frequency foldback eliminate input current ■ IQ in Shutdown <1µA surge during start-up. An optional internal regulated active ■ Internal y Compensated load at the output via the BD pin keeps the LT3686A at ■ Thermal y Enhanced MSOP and 3mm × 3mm DFN full switching frequency at light loads, resulting in low, Packages predictable output ripple above the audio and AM bands.
ApplicAtions
Internal compensation and an internal boost diode reduce external component count. ■ Automotive Systems The LT3686A offers external synchronization capability, ■ Battery-Powered Equipment whereas the LT3686 does not. ■ Wal Transformer Regulation L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks ■ Distributed Supply Regulation of Linear Technology Corporation. All other trademarks are the property of their respective owners.
typicAl ApplicAtion 3.3V Step-Down Converter 12VIN Efficiency (2MHz)
90 VIN V 6V TO 37V IN BD 80 3.3V 2.2µF OUT EN/UVLO BOOST 0.22µF 70 5V 2MHz LT3686A OUT 6.8µH 60 SYNC/MODE SW VOUT 3.3V 50 MBRM140 SS 1.2A 40 DA 10nF RT 31.6k EFFICIENCY (%) FB 30 GND 20 31.6k 10k 22µF 10 3686A TA01a 0 0 200 400 600 800 1000 1200 (VIN 6V TO 16V AT 2MHz) LOAD CURRENT (mA) 3686A TA01b 3686afa 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
