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LT4363 - High Voltage Surge Stopper with Current Limit

LTC2960 - 36V Nano-Current Two Input Voltage Monitor

LTC3728 - Dual, 550kHz, 2-Phase Synchronous Step-Down Switching Regulator

Features

  • Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
  • OPTI-LOOP Compensation Minimizes COUT
  • ±1% Output Voltage Accuracy
  • Power Good Output Voltage Indicator
  • Phase-Lockable Fixed Frequency 250kHz to 550kHz
  • Dual N-Channel MOSFET Synchronous Drive
  • Wide VIN Range: 3.5V to 36V Operation
  • Very Low Dropout Operation: 99% Duty Cycle
  • Adjustable Soft-Start Current Ramping
  • Foldback Output Current Limiting
  • Latched Short-Circuit Shutdown with Defeat Option
  • Output Overvoltage Protection
  • Remote Output Voltage Sense
  • Low Shutdown IQ : 20µA
  • 5V and 3.3V Regulators
  • 3 Selectable Operating Modes: Constant-Frequency, Burst Mode Operation and PWM
  • Available in 32-Pin 5mm x 5mm QFN and 28-Pin SSOP Packages

Typical Application

LTC3728 Typical Application

Description

The LTC3728 is a dual high performance step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant-frequency current mode architecture allows phase-lockable frequency of up to 550kHz. Power loss and noise due to the ESR of the input capacitors are minimized by operating the two controller output stages out of phase.

OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The precision 0.8V reference and power good output indicator are compatible with future microprocessor generations, and a wide 3.5V to 30V (36V maximum) input supply range encompasses all battery chemistries.

A RUN/SS pin for each controller provides both softstart and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when overcurrent latchoff is disabled. Output overvoltage protection circuitry latches on the bottom MOSFET until VOUT returns to normal. The FCB mode pin can select among Burst Mode, constant-frequency mode and continuous inductor current mode or regulate a secondary winding. The LTC3728 includes a power good output pin that indicates when both outputs are within 7.5% of their designed set point.

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

QFN-32, SSOP-28

LTC3728 Package Drawing
LTC3728 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3728EG SSOP 28 E $5.92 $5.00 View
LTC3728EG#PBF SSOP 28 E $5.92 $5.00 View
LTC3728EG#TR SSOP 28 E $5.10 View
LTC3728EG#TRPBF SSOP 28 E $5.10 View
LTC3728EUH QFN 32 E $7.50 $5.10 View
LTC3728EUH#PBF QFN 32 E $7.50 $5.10 View
LTC3728EUH#TR QFN 32 E $5.20 View
LTC3728EUH#TRPBF QFN 32 E $5.20 View
LTC3728IG#PBF SSOP 28 I $7.56 $5.29 View
LTC3728IG#TRPBF SSOP 28 I $5.35 View
LTC3728IUH#PBF QFN 32 I $7.73 $5.41 View
LTC3728IUH#TRPBF QFN 32 I $5.47 View
LTC3728LCGN SSOP 28 C $6.25 $4.40 View
LTC3728LCGN#PBF SSOP 28 C $6.25 $4.40 View
LTC3728LCGN#TR SSOP 28 C $4.50 View
LTC3728LCGN#TRPBF SSOP 28 C $4.50 View
LTC3728LCUH QFN 32 C $6.52 $4.55 View
LTC3728LCUH#PBF QFN 32 C $6.52 $4.55 View
LTC3728LCUH#TR QFN 32 C $4.65 View
LTC3728LCUH#TRPBF QFN 32 C $4.65 View
LTC3728LEGN SSOP 28 E $6.61 $4.65 View
LTC3728LEGN#PBF SSOP 28 E $6.61 $4.65 View
LTC3728LEGN#TR SSOP 28 E $4.75 View
LTC3728LEGN#TRPBF SSOP 28 E $4.75 View
LTC3728LEGN-1 SSOP 28 E $6.64 $4.65 View
LTC3728LEGN-1#PBF SSOP 28 E $6.64 $4.65 View
LTC3728LEGN-1#TR SSOP 28 E $4.71 View
LTC3728LEGN-1#TRPBF SSOP 28 E $4.71 View
LTC3728LEUH QFN 32 E $6.88 $4.80 View
LTC3728LEUH#PBF QFN 32 E $6.88 $4.80 View
LTC3728LEUH#TR QFN 32 E $4.90 View
LTC3728LEUH#TRPBF QFN 32 E $4.90 View
LTC3728LEUH-1 QFN 32 E $6.86 $4.80 View
LTC3728LEUH-1#PBF QFN 32 E $6.86 $4.80 View
LTC3728LEUH-1#TR QFN 32 E $4.86 View
LTC3728LEUH-1#TRPBF QFN 32 E $4.86 View
LTC3728LIGN#PBF SSOP 28 I $8.10 $5.25 View
LTC3728LIGN#TRPBF SSOP 28 I $5.31 View
LTC3728LIGN-1#PBF SSOP 28 I $6.80 $4.76 View
LTC3728LIGN-1#TRPBF SSOP 28 I $4.82 View
LTC3728LIUH#PBF QFN 32 I $8.10 $5.25 View
LTC3728LIUH#TRPBF QFN 32 I $5.31 View
LTC3728LIUH-1#PBF QFN 32 I $7.06 $4.94 View
LTC3728LIUH-1#TRPBF QFN 32 I $5.00 View
LTC3728LXCUH QFN 32 C $6.16 $4.30 View
LTC3728LXCUH#PBF QFN 32 C $6.16 $4.30 View
LTC3728LXCUH#TR QFN 32 C $4.40 View
LTC3728LXCUH#TRPBF QFN 32 C $4.40 View
LTC3728LZEUH#PBF QFN 32 E $6.20 $4.34 View
LTC3728LZEUH#TRPBF QFN 32 E $4.40 View
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC392A-B LTC3728EUH | High Efficiency Dual Regulator, 5V to 24Vin, 3.3Vout @ 5A, 5Vout @ 4A $125.00
DC447A LTC3728EUH | 2-Phase Dual Output Power Supply, Vin = 5V - 14V, Vout1 = 2.5V @ 13A, Vout2 = 1.8V @ 13A $150.00
DC542A LTC3728EG | Dual 2-Phase Synchronous Step-Down Regulator, 8V to 24V Input, 5V/3.3V 0A to 12A, 3.3V/2.5V 0A to 12A $150.00
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Click here to view our complete list of demo boards

Applications

  • Notebook and Palmtop Computers
  • Telecom Systems
  • Portable Instruments
  • Battery-Operated Digital Devices
  • DC Power Distribution Systems

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Related models available in LTspice IV
LTC3728
LTC3728L

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