LTC7149 - 60V, 4A Synchronous Step-Down Regulator for Inverting Outputs

Features

  • Wide VIN Range: 3.4V to 60V
  • Wide VOUT Range: 0V to –28V
  • Single Resistor VOUT Programming
  • Integrated 110mΩ Top N-Channel/50mΩ Bottom N-Channel MOSFETs
  • Regulated IQ: 440μA, Shutdown IQ: 15μA
  • Board GND Referenced I/O Pins (RUN, PGOOD, MODE/SYNC)
  • Accurate Resistor Programmable Frequency (300kHz to 3MHz) with ±50% Frequency Sync Range
  • 92% Efficiency with 12 VIN and –5VOUT
  • ±0.8% Output Voltage Accuracy
  • Peak Current Mode Operation
  • Burst Mode® Operation, Forced Continuous Mode
  • Programmable Soft-Start
  • Overtemperature Protection
  • Available in 28-Lead (4mm x 5mm) QFN and TSSOP Packages

Typical Application

LTC7149 Typical Application
LTC7149 Typical Application

Description

The LTC®7149 is a high efficiency 60V, 4A synchronous monolithic step-down regulator for inverting output applications. The regulator features a single resistorprogrammable output voltage and high efficiency over a wide VOUT range.

The inverting regulator operates from an input voltage range of 3.4V to 60V and provides an adjustable output from (–28V) to zero volts while delivering up to 4A of inductor current. The switching frequency is also set with an external resistor. A user-selectable mode input is provided to allow the user to trade off ripple noise for efficiency at light loads; Burst Mode operation provides the highest efficiency at light loads, while forced continuous mode provides low output ripple. The MODE/SYNC pin can also be used to synchronize the switching frequency to an external clock. Internal level-shift circuits allow the I/O pins (RUN, MODE/SYNC, PGOOD) to be referenced to board GND.

The LTC7149 operates with a peak current mode architecture that allows for fast transient response with inherent cycle-to-cycle current limit protection.

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
LTC7149EFE#PBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LTC7149EFE#TRPBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LTC7149EUFD#PBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC7149EUFD#TRPBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC7149IFE#PBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LTC7149IFE#TRPBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LTC7149IUFD#PBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LTC7149IUFD#TRPBF 4x5 QFN-28 UFD I 05-08-1712 Yes


LTC7149 Package Drawing
LTC7149 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
LTC7149EFE#PBF TSSOP-28 E $8.43 $5.90 Yes
LTC7149EFE#TRPBF TSSOP-28 E $8.49 $5.96 Yes
LTC7149EUFD#PBF 4x5 QFN-28 E $8.07 $5.65 Yes
LTC7149EUFD#TRPBF 4x5 QFN-28 E $8.13 $5.71 Yes
LTC7149IFE#PBF TSSOP-28 I $9.70 $6.79 Yes
LTC7149IFE#TRPBF TSSOP-28 I $9.76 $6.85 Yes
LTC7149IUFD#PBF 4x5 QFN-28 I $9.29 $6.50 Yes
LTC7149IUFD#TRPBF 4x5 QFN-28 I $9.35 $6.56 Yes
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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
DC2354A LTC7149 Demo Board | Buck Configured as Negative VOUT; 3.5V ≤ VIN ≤ 55V; Vout = -3.3V/-5V/Adj to -56V @ Up to 4A $150.00
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Click here to view our complete list of demo boards

Applications

  • Industrial Applications
  • Telecom Power Supplies
  • Distributed Power 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

To launch a ready to run LTspice demonstration circuit for this part:

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LTC7149

LTpowerCAD

The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:
LTC7149

Technical Support