LTC3850 - Dual, 2-Phase Synchronous Step-Down Switching Controller

LTC6908 - Dual Output Oscillator with Spread Spectrum Modulation
LTC6909 - 1 to 8 Output, Multiphase Silicon Oscillator with Spread Spectrum Modulation

LTC3728L - Dual, 550kHz, 2-Phase Synchronous Regulators

Features

  • Click Here For LTC3728L Evaluation Kits
  • Dual, 180° Phased Controllers Reduce Required
    Input Capacitance and Power Supply Induced Noise
  • OPTI-LOOP® Compensation Minimizes COUT
  • ±1% Output Voltage Accuracy (LTC3728LC)
  • Power Good Output Voltage Indicator
  • Phase-Lockable Fixed Frequency 250kHz to 550kHz
  • Dual N-Channel MOSFET Synchronous Drive
  • Wide VIN Range: 4.5V to 28V 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
  • Low Shutdown IQ: 20µA
  • 5V and 3.3V Standby Regulators
  • 3 Selectable Operating Modes: Constant Frequency, Burst Mode® Operation and PWM
  • 5mm x 5mm QFN and 28-Lead Narrow SSOP Packages

Typical Application

LTC3728L
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Description

The LTC3728L/LTC3728LX are dual high performance step-down switching regulator controllers that drive 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 4.5V to 28V (30V maximum) input supply range encompasses all battery chemistries.

A RUN/SS pin for each controller provides both soft-start 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 LTC3728L/LTC3728LX include a power good output pin that indicates when both outputs are within 7.5% of their designed set point.

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Packaging

QFN-32

LTC3728L
LTC3728L
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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.

Evaluation Kits

Part Number Description Price
DC392A-A LTC1628CUH | High Efficiency Dual Regulator, 5V to 24Vin, 3.3Vout @ 5A, 5Vout @ 4A $125.00
DC392A-B LTC3728EUH | High Efficiency Dual Regulator, 5V to 24Vin, 3.3Vout @ 5A, 5Vout @ 4A $125.00
DC392A-C LTC3728LEUH | High Efficiency Dual Regulator, 5V to 24Vin, 3.3Vout @ 5A, 5Vout @ 4A $125.00
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Applications

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

To simulate selected Linear Technology products, please download LTSpice / SwitcherCAD III. This powerful schematic capture and simulation tool includes macro models for 80% of Linear Technology's switching regulators, over 200 op amp models, as well as resistors, transistors and MOSFET models.

For other simulation tools, visit our Design Simulation and Device Models page.

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