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ADP1821:  Step-Down DC-to-DC Controller

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 ...More

ADP1821:  Step-Down DC-to-DC Controller

Product Description

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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    • 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
    • Vin Range: 3.7V-5.5V
    • Vout : Adj
    • Step Up: No
    • Shutdown: Y
    • Pkg: QSOP-16

    Circuit Diagram for ADP1821

    Similar Products

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    Part# Vin Range Pwr Stage Vin Vout Adj Options Multi-Output Shutdown Current Supply Current Switching Frequency Iout (max) Synchronous Step Down Step Up Pkg Product Description Price* (1000-4999)
    ADP1621 2.9V-5.5V As Low As 1V Lossless ISens@<30V Vout, Resistor ISens@>30V No 10µA 3mA 100 KHz - 1.5 MHz - No No Yes MSOP-10 Constant-Frequency, Current-Mode, Step-Up DC/DC Controller $1.32
    ADP1821 3.7V-5.5V 1V-24V 0.6V to 85% PwrStgVin No 10µA 2mA 300 kHz -600 kHz, Sync up to 1 MHz 20A Yes Yes No QSOP-16 20 A Step-Down DC-DC Controller $1.37
    ADP1822 3.7V-5.5V 1V-24V 0.6V to 85% PwrStgVin No 10µA 2mA 300 kHz-600 kHz; Sync up to 1 MHz 20A Yes Yes No QSOP-24 20 A, PWM, Step-Down DC-DC Controller with Margining and Tracking $1.42
    ADP1823 3.7V-20V 1V-24V 0.6V to 85% PwrStgVin Yes 20µA 3mA 300 kHz-600 kHz, Sync up to 1 MHz 20A Yes Yes No LFCSP-32 Versatile Dual, Interleaved Synchronous PWM Buck Controller w/ Tracking $2.13
    ADP1828 3V-20V 1V-24V 0.6V to 85% PwrStgVin No 15µA 3mA 300 kHz to 600 kHz - Yes Yes No QSOP-20 Synchronous Buck PWM, Step-Down, DC-to-DC Controller $1.52
    ADP1829 3V-20V 1V-24V 0.6V to 85% PwrStgVin Yes 20µA 3mA 300 kHz-600 kHz, Sync up to 1 MHz 20A Yes Yes - LFCSP-32 Dual, Interleaved, Step-Down DC-to-DC Controller w/ Tracking $2.13
    ADP1864 3.15V-14V 3.15V-14V 0.8V to Vin No 15µA 350µA 580 kHz 5A No Yes No TSOT-6 5A, Constant Frequency, Current-Mode Step-Down DC/DC Controller in TSOT $1.06
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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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
    **Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.