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Overview
Features and Benefits
- 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 Required 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
- Selectable Current Limit
- Very Low Dropout Operation: 99% Duty Cycle
- Adjustable Output Voltage Soft-Start or Tracking
- Power Good Output Voltage Monitors
- Output Overvoltage Protection
- Low Shutdown IQ : < 14μA
- Internal LDO Powers Gate Drive from VIN or EXTVCC
- No Current Foldback During Start-Up
- Small Low Profile (0.75mm) 5mm × 5mm QFN Package
Product Details
The LTC3890 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 phase-lockable frequency of up to 850kHz. Power loss and noise due to the ESR of the input capacitor are minimized by operating the two controller output stages out-of-phase.
The 50μA no-load quiescent current extends operating run time in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3890 features a precision 0.8V reference and power good output indicators. 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 foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous conduction mode at light loads. For a leaded package version (28-lead Narrow SSOP), see the LTC3890-1 data sheet.
| LTC3890 | LTC3890-1 | LTC3890-2 | LTC3890-3 | |
| Adjustable Current Limit | 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 | 5 × 5 QFN-32 | SSOP-28 | 5 × 5 QFN-32 | SSOP-28 |
Applications
- Automotive Always-On Systems
- Battery Operated Digital Devices
- Distributed DC Power Systems
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Documentation
Reliability Data (1)
Evaluation Kit Manuals (1)
Design Notes (3)
Tools & Simulations
LTspice
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, 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.
LTspice Simulations
Models for the following parts are available in LTspice:
LTpowerCAD
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
Design tools for the following parts are available in LTpowerCAD:
Reference Materials
Product Selector Card (1)
Product Selection Guide (1)
Technical Articles (1)
Design Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
