LTC1628 - High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator

Features

  • Out-of-Phase Controllers Reduce Required Input
    Capacitance and Power Supply Induced Noise
  • OPTI-LOOP™ Compensation Minimizes COUT
  • Dual N-Channel MOSFET Synchronous Drive
  • ±1% Output Voltage Accuracy
  • Power Good Output Voltage Monitor (LTC1628-PG)
  • DC Programmed Fixed Frequency 150kHz to 300kHz
  • 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 Standby Regulators
  • Small 28-Lead SSOP Package
  • Selectable Constant Frequency or Burst Mode® Operation
  • Available in 5mm x 5mm QFN and 28-Pin SSOP Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC1628 Typical Application

Description

The LTC1628/LTC1628-PG are high performance dual step-down switching regulator controllers that drive all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows adjustment of the frequency up to 300kHz. 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 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 LTC1628-PG includes a power good output pin that replaces the FLTCPL, fault coupling control pin of the LTC1628.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

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

Part Number Package Code Temp Package
Drawing
RoHS
LTC1628CG-PG#PBF SSOP-28 G C 05-08-1640 (G28) Yes
LTC1628CG-PG#TRPBF SSOP-28 G C 05-08-1640 (G28) Yes
LTC1628CG#PBF SSOP-28 G C 05-08-1640 (G28) Yes
LTC1628CG#TRPBF SSOP-28 G C 05-08-1640 (G28) Yes
LTC1628CUH#PBF 5x5 QFN-32 UH C 05-08-1693 Yes
LTC1628CUH#TRPBF 5x5 QFN-32 UH C 05-08-1693 Yes
LTC1628IG-PG#PBF SSOP-28 G I 05-08-1640 (G28) Yes
LTC1628IG-PG#TRPBF SSOP-28 G I 05-08-1640 (G28) Yes
LTC1628IG#PBF SSOP-28 G I 05-08-1640 (G28) Yes
LTC1628IG#TRPBF SSOP-28 G I 05-08-1640 (G28) Yes
LTC1628IUH#PBF 5x5 QFN-32 UH I 05-08-1693 Yes
LTC1628IUH#TRPBF 5x5 QFN-32 UH I 05-08-1693 Yes


LTC1628 Package Drawing
LTC1628 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC1628CG-PG#PBF SSOP-28 C $5.45 $4.65 Yes
LTC1628CG-PG#TRPBF SSOP-28 C $4.76 Yes
LTC1628CG#PBF SSOP-28 C $5.20 $4.45 Yes
LTC1628CG#TRPBF SSOP-28 C $4.55 Yes
LTC1628CUH#PBF 5x5 QFN-32 C $6.70 $4.55 Yes
LTC1628CUH#TRPBF 5x5 QFN-32 C $4.65 Yes
LTC1628IG-PG#PBF SSOP-28 I $6.50 $5.55 Yes
LTC1628IG-PG#TRPBF SSOP-28 I $5.66 Yes
LTC1628IG#PBF SSOP-28 I $6.30 $5.35 Yes
LTC1628IG#TRPBF SSOP-28 I $5.45 Yes
LTC1628IUH#PBF 5x5 QFN-32 I $8.04 $5.45 Yes
LTC1628IUH#TRPBF 5x5 QFN-32 I $5.55 Yes
Buy NowRequest Samples
* 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
DC236C-A LTC1628CG | Hi Efficiency, Multi-Phase 2-Output, Current Mode Controller, 5-30Vin, 5V/4A and 3.3V/4A Output $125.00
DC236C-C LTC1628CG-PG | Hi Efficiency, Multi-Phase 2-Output, Current Mode Controller, 5-30Vin, 5V/4A and 3.3V/4A Output $125.00
DC264A LTC1628CG | Multi-Phase, 3 Output Regulator, 7-28Vin; 5V @ 3A, 3.3V @ 4A and a Linear 12V @ 150mA $125.00
DC265A LTC1628CG | Multi-Phase, 3 Output Regulator, 7-28Vin; 5V @ 3A, 3.3V @ 4A and a Synchronous 12V @ 200mA Contact Factory
DC271A LTC1628CG | Dual Phase Multi-Output High Current Converter, 7V to 24V Input, Vout1 = 5V @ 12A Max., Vout2 = 3.3V @ 12A Max. Contact Factory
DC392A-A LTC1628CUH Demo Board | Dual Output, 5V to 24Vin, 5Vout1 @ 4A, 3.3Vout2 @ 5A $125.00
DC543A LTC2920-2CMS8 LTC1628CG | LTC2920 with Dual DC to DC Converter, 7V to 24V Input, 5V @ 12A max = Vout1, 3.3V @ 12A max = Vout2 $100.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC1628IG-PG#PBF SSOP-28 I $6.50 $5.55 Yes
LTC1628IG-PG#TRPBF SSOP-28 I $5.66 Yes
LTC1628IG#PBF SSOP-28 I $6.30 $5.35 Yes
LTC1628IG#TRPBF SSOP-28 I $5.45 Yes
LTC1628IUH#PBF 5x5 QFN-32 I $8.04 $5.45 Yes
LTC1628IUH#TRPBF 5x5 QFN-32 I $5.55 Yes
Buy NowRequest Samples
* 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.

Applications

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

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC1628
LTC1628-PG
LTC1628-SYNC

Technical Support