The ADP1872/ADP1873 are versatile current-mode, synchronous step-down controllers that provide superior transient response, optimal stability, and current limit protection by using a constant on-time, pseudo-fixed frequency with a programmable current-sense gain, current-control scheme. In addition, these devices offer optimum performance at low duty cycles by utilizing valley current-mode control architecture. This allows the ADP1872/ ADP1873 to drive all N-channel power stages to regulate output voltages as low as 0.6 V.
The ADP1873 is the power saving mode (PSM) version of the device and is capable of pulse skipping to maintain output regulation while achieving improved system efficiency at light loads (see the Power Saving Mode (PSM) Version (ADP1873) section for more information).
Available in three frequency options (300 kHz, 600 kHz, and 1.0 MHz, plus the PSM option), the ADP1872/ADP1873 are well suited for a wide range of applications. These ICs not only operate from a 2.75 V to 5.5 V bias supply, but also can accept a power input as high as 20 V.
In addition, an internally fixed soft start period is included to limit input in-rush current from the input supply during startup and to provide reverse current protection during soft start for a pre-charged output. The low-side current-sense, current-gain scheme and integration of a boost diode, along with the PSM/forced pulse-width modulation (PWM) option, reduce the external part count and improve efficiency.
The ADP1872/ADP1873 operate over the −40°C to +125°C junction temperature range and are available in a 10-lead MSOP.Applications
|Title||Content Type||File Type|
|ADP1872/ADP1873: Synchronous Current-Mode with Constant On-Time, PWM Buck Controller Data Sheet (Rev B, 07/2012) (pdf, 2049 kB)||Data Sheets|
AN-1075: Synchronous Inverse SEPIC Using the ADP1870/ADP1872 Provides High Efficiency for Noninverting Buck/Boost Applications
(pdf, 167 kB)
Discusses using the ADP1870/ADP1872 as an inverse single-ended primary inductor converter (SEPIC), also known as the Zeta converter, that can operate in either buck or boost mode, decreasing or increasing the input voltage to a desired regulated voltage, with minimal cost, component count, and power loss.
|CN-0190: Robust, Multivoltage, High Efficiency, 25 W Universal Power Supply Module with 6 V to 14 V Input (pdf, 357 kB)||Circuit Note|
Introduction to ADIsimPower
ADIsimPower is a smart selector and a collection of downloadable tools that produce complete and optimized power designs. Schematic, bill of materials, and performance data are customized to your specific needs in minutes.
|UG-057: Evaluating the ADP1872/ADP1873 PWM Buck Controllers (pdf, 1277 kB)||User Guides|
|Glossary of EE Terms||Glossary||HTML|
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ADP187x Buck Designer Tool
Microsoft Excel download tool from ADIsimPower to generate a power supply design complete with a schematic, bill of materials, and performance specifications.
|ADIsim Design/Simulation Tools||ZIP|
Download files for ADIsimPower™ Voltage Regulator Design Tool
The individual Excel-based voltage regulator design tools used in ADIsimPower™.
|ADIsim Design/Simulation Tools||HTML|
Blank/Unpopulated boards need to be ordered through the appropriate download tool from ADIsimPower.
ADP1872 Evaluation Board
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.
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