LTC3890-3 - 60V Low IQ, Dual, 2-Phase Synchronous Step-Down DC/DC Controller

Features

  • Wide VIN Range: 4V to 60V (65V Abs Max)
  • Low Operating IQ: 50μA (One Channel On)
  • Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
  • RSENSE or DCR Current Sensing
  • Out-of-Phase Controllers Reduce Input Capacitance and Power Supply Induced Noise
  • Phase-Lockable Frequency (75kHz to 850kHz)
  • Programmable Fixed Frequency (50kHz to 900kHz)
  • Selectable Continuous, Pulse-Skipping or Low Ripple Burst Mode® Operation at Light Loads
  • Very Low Dropout Operation: 99% Duty Cycle
  • Adjustable Output Voltage Soft-Start or Tracking
  • Power Good Output Voltage Monitor
  • Low Shutdown IQ: <14μA
  • Internal LDO Powers Gate Drive from VIN or EXTVCC
  • Narrow SSOP Package

Typical Application

LTC3890-3 Typical Application
LTC3890-3 Typical Application

Description

The LTC®3890-3 is a high performance dual step-down switching regulator DC/DC controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phaselockable frequency of up to 850kHz. Power loss and supply noise are minimized by operating the two controller output stages out-of-phase.

The 50μA no-load quiescent current extends operating life in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. A wide 4V to 60V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries.

Independent TRACK/SS pins for each controller ramp the output voltages during start-up. Current mode control limits the inductor current during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous conduction mode at light loads.

For versions with different and/or additional features, see the LTC3890 family summary, Table 1, in the Pin Functions section of this data sheet.

 LTC3890LTC3890-1LTC3890-2LTC3890-3
Adjustable Current Limit Yes No Yes No
CLKOUT/PHASMD for
Multiphase Operation
Yes No Yes No
Number of PGood
Outputs
2 1 2 1
OVP – Bottom Gate
Crowbar
Yes Yes No No
Current Limit Foldback Yes Yes No No
Light Load Operation
when Synced to External
Clock
Forced Continuous Forced Continuous Pulse Skipping Pulse Skipping
SENSE Pins Common
Mode Range
Common Mode < 0.5V
Requires VFB < 0.65V
Common Mode < 0.5V
Requires VFB < 0.65V
Not Dependant on
VFB. Easy to make a
non-synchronous
Boost or SEPIC
Not Dependant on
VFB. Easy to make a
non-synchronous
Boost or SEPIC
Package 5X5 QFN-32 SSOP-28 5X5 QFN-32 SSOP-28

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
LTC3890EGN-3#PBF SSOP-28 GN E 05-08-1641 (GN28) Yes
LTC3890EGN-3#TRPBF SSOP-28 GN E 05-08-1641 (GN28) Yes
LTC3890HGN-3#PBF SSOP-28 GN H 05-08-1641 (GN28) Yes
LTC3890HGN-3#TRPBF SSOP-28 GN H 05-08-1641 (GN28) Yes
LTC3890IGN-3#PBF SSOP-28 GN I 05-08-1641 (GN28) Yes
LTC3890IGN-3#TRPBF SSOP-28 GN I 05-08-1641 (GN28) Yes
LTC3890MPGN-3#PBF SSOP-28 GN MP 05-08-1641 (GN28) Yes
LTC3890MPGN-3#TRPBF SSOP-28 GN MP 05-08-1641 (GN28) Yes


LTC3890-3 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
LTC3890EGN-3#PBF SSOP-28 E $6.39 $4.47 Yes
LTC3890EGN-3#TRPBF SSOP-28 E $4.53 Yes
LTC3890HGN-3#PBF SSOP-28 H $7.82 $5.47 Yes
LTC3890HGN-3#TRPBF SSOP-28 H $5.53 Yes
LTC3890IGN-3#PBF SSOP-28 I $7.40 $5.18 Yes
LTC3890IGN-3#TRPBF SSOP-28 I $5.24 Yes
LTC3890MPGN-3#PBF SSOP-28 MP $22.10 $15.47 Yes
LTC3890MPGN-3#TRPBF SSOP-28 MP $15.53 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
DC2299A-A LTC3890EGN-3 Demo Board | 6V ≤ VIN ≤ 60V; VOUT1 = 5V @ 8A, VOUT2 = 12V @ 5A Contact Factory
Buy Now
Click here to view our complete list of demo boards

Applications

  • Automotive Always-On Systems
  • Battery Operated Digital Devices
  • Distributed DC 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:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

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

Models for the following parts are available in LTspice:
LTC3890
LTC3890-1
LTC3890-2
LTC3890-3

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:
LTC3890
LTC3890 Parallel
LTC3890-1
LTC3890-2
LTC3890-2 Parallel

Technical Support