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-1 - Dual, 550kHz, 2-Phase Synchronous Regulator

Features

  • Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
  • OPTI-LOOP Compensation Minimizes COUT
  • ±1.5% Output Voltage Accuracy
  • Power Good Output Voltage Indicator
  • Phase-Lockable Fixed Frequency 250kHz to 550kHz
  • Over Current Latchoff Disabled
  • Wide VIN Range: 4.5V to 28V (35V for LTC3728LI-1) Operation
  • Very Low Dropout Operation: 99% Duty Cycle
  • Adjustable Soft-Start Current Ramping
  • Foldback Output Current Limiting
  • 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 × 5mm QFN and 28-Lead Narrow SSOP Packages

Typical Application

LTC3728L-1
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Description

The LTC3728L-1 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. The LTC3728L-1 is identical to the LTC3728L except that the LTC3728L-1 lacks the over current latchoff feature.

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 microproces- sor generations, and a wide 4.5V to 28V (30V maximum/ 35V for LTC3728LI-1) input supply range encompasses all battery chemistries.

A RUN/SS pin for each controller provides soft-start. Current foldback limits MOSFET dissipation during short- circuit conditions. The FCB mode pin can select among Burst Mode operation, constant frequency mode and continuous inductor current mode or regulate a secondary winding. The LTC3728L-1 includes a power good output pin that indicates when both outputs are within 7.5% of their designed set point.
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Packaging

SSOP-28, QFN-32

LTC3728L-1
LTC3728L-1
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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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