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ADP1821:  Step-Down DC-to-DC Controller

Product Status:Production
Data
Sheet
ADP1821 Data Sheet Rev C, 04/2007 (pdf 808kB)

Product Details

Product Status:Production
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The ADP1821 is a versatile and inexpensive, synchronous, pulse-width-modulated (PWM), voltage-mode, step-down controller. It drives an all N-channel power stage to regulate an output voltage as low as 0.6 V. The ADP1821 can be configured to provide output voltages from 0.6 V to 85% of the input voltage and is sized to handle large MOSFETs for point-of-load regulators.

The ADP1821 is well suited for a wide range of high power applications, such as DSP and processor core power in telecommunications, medical imaging, high performance servers, and industrial applications. It operates from a 3.7 V to 5.5 V supply with a power input voltage ranging from 1.0 V to 24 V.

The ADP1821 operates at a pin-selectable, fixed switching frequency of either 300 kHz or 600 kHz, minimizing external component size and cost. For noise sensitive applications, it can be synchronized to an external clock to achieve switching frequencies between 300 kHz and 1.2 MHz. The ADP1821 includes soft start protection to limit the inrush current from the input supply during startup, reverse current protection during soft start for precharged outputs, as well as a unique adjustable lossless current-limit scheme utilizing external MOSFET sensing.

The ADP1821 operates over the –40°C to +125°C junction temperature range and is available in a 16-lead QSOP.

Applications

  • Telecommunications and networking systems
  • Set-top boxes
  • Printers
  • Servers
  • Medical imaging systems
  • Microprocessor and DSP core power supplies
  • Mobile communication base stations

    • Data Sheet, Rev. C, 4/07

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    FEATURES and BENEFITS

    • Wide power-input voltage range: 1 V to 24 V
    • Chip supply voltage range: 3.7 V to 5.5 V
    • Wide output voltage range: 0.6 V to 85% of input voltage
    • 1% accuracy, 0.6 V reference voltage
    • All N-channel MOSFET design for low cost
    • Fixed-frequency operation 300 kHz, 600 kHz, or synchronized operation up to 1.2 MHz
    • No current sense resistor required
    • Power-good output
    • Programmable soft start with reverse current protection
    • Soft start, thermal overload, current-limit protection
    • Undervoltage lockout
    • 10 μA shutdown supply current

    Circuit Diagram for ADP1821

    ADP1821 Diagram
    Typical Applications and Other Diagrams

    Documentation

    Title Content Type File Type
    ADP1821: Step-Down DC-to-DC Controller Data Sheet (Rev C, 04/2007) (pdf, 808 kB) Data Sheets PDF
    AN-911: A Detailed Guide to Powering the TigerSHARC Processors  (pdf, 239 kB) Application Notes PDF
    ADP1823, ADP2106, ADP1821 Reference Design  (pdf, 189 kB)
    Six Output Voltages: 1.2 V, 1.8 V, 2.5 V, 3.3 V, 5 V, 12 V; Output Current: 1 A to 4.5 A; Input voltage: 14.4-20.0 V; Ripple 2% ppk of Output Voltage; Transient step ±5%, 50% max load     		Power Reference Designs PDF
    ADP1821 Reference Design  (pdf, 1251 kB)
    Two Output Voltages: 1.5 V, 1.2 V; Output Current: each 20 A; Input voltage: 12 V; DC plus Ripple <±2% of Output Voltage; Transient step ±5%, 50% max load     		Power Reference Designs PDF
    ADP1829 & ADP1821 Reference Design  (pdf, 309 kB)
    Five Output Voltages: 1.2 V, 1.8 V, 3.3 V, 5 V, 12 V; Output Current: 1 A to 4.5 A; Input voltage: 15.2-16.8 V; Ripple 50 mV ppk; Transient step ±5%, 50% max load     		Power Reference Designs PDF
    ADP1821 Reference Design  (pdf, 0)
    Single Output Voltage: 5.0 V; Output Current: 1.4 A; Input voltage: 9 V to 20 V; Ripple <1% ppk of Output Voltage; Transient step ±5%, 50% max load     		Power Reference Designs PDF
    ADP1821 Reference Design  (pdf, 103 kB)
    One Output Voltage: 5 V; Output Current: 4 A; Input voltage: 12.0-44.0 V; Ripple 2% ppk of Output Voltage; Transient step ±5%, 50% max load     		Power Reference Designs PDF
    DC-to-DC Switching Regulator IC Solutions (10/06)  (pdf, 3205 kB) Overview PDF
    RAQs index Rarely Asked Questions HTML
    Glossary of EE Terms Glossary HTML

    Design Tools,Models,Drivers & Software

    Title Content Type File Type
    Download files for ADIsimPower™ Voltage Regulator Design Tool
    The individual Excel-based voltage regulator design tools used in ADIsimPower™.     		ADIsim Design/Simulation Tools HTML
    Enter values and click on ADIsimPower to find power management solutions. Launch of ADIsimPower Voltage Regulator Design Tool
    Available System Voltage Operating Voltage Rail Load Current
    Vin (min) V Vin (max) V Vout V Iout A

    Evaluation Kits & Symbols & Footprints

    Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

    Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

    SampleSample & Buy

    Price, packaging, availability

    ADP1821 Model Options
    Price Table Help

    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.

    ADP1821 Evaluation Board for 20 A Step-Down
    Model Description Price RoHS View PCN/ PDN Check Inventory/
    Purchase/Sample
    ADP1821-EVALZ Status: Production Evaluation Board $60.72 Yes -

    Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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