ADP1821 Analog Devices Data Sheet Manual
Summary
The ADP1821 is a high-performance, synchronous DC-to-DC step-down controller ideal for point-of-load power applications requiring extreme reliability. Featuring wide input voltage support (1V–24V) and built-in protections like soft start and thermal shutdown, it delivers efficient power regulation for complex systems. This resource provides detailed specifications and application guidance for engineers designing professional electronics in sectors like telecommunications, data servers, medical imaging, and industrial control.
Page 1 Text Content
Step-Down DC-to-DC Controller
ADP1821 FEATURES GENERAL DESCRIPTION Wide power-input voltage range: 1 V to 24 V The ADP1821 is a versatile and inexpensive, synchronous, Chip supply voltage range: 3.7 V to 5.5 V pulse-width-modulated (PWM), voltage-mode, step-down Wide output voltage range: 0.6 V to 85% of input voltage controller. It drives an all N-channel power stage to regulate an 1% accuracy, 0.6 V reference voltage output voltage as low as 0.6 V. The ADP1821 can be configured All N-channel MOSFET design for low cost to provide output voltages from 0.6 V to 85% of the input Fixed-frequency operation 300 k Hz, 600 k Hz, or voltage and is sized to handle large MOSFETs for point-of-load synchronized operation up to 1.2 MHz regulators. No current sense resistor required
The ADP1821 is well suited for a wide range of high power
Power-good output
applications, such as DSP and processor core power in telecom-
Programmable soft start with reverse current protection
munications, medical imaging, high performance servers, and
Soft start, thermal overload, current-limit protection
industrial applications. It operates from a 3.7 V to 5.5 V supply
Undervoltage lockout
0- with a power input voltage ranging from 1.0 V to 24 V.
10 μA shutdown supply current
The ADP1821 operates at a pin-selectable, fixed switching
Small, 16-lead QSOP
frequency of either 300 k Hz or 600 k Hz, minimizing external
APPLICATIONS
component size and cost. For noise sensitive applications, it
Telecommunications and networking systems EF FI IE can be synchronized to an external clock to achieve switching Set-top boxes frequencies between 300 k Hz and 1.2 MHz. The ADP1821 Printers includes soft start protection to limit the inrush current from Servers the input supply during startup, reverse current protection Medical imaging systems during soft start for precharged outputs, as well as a unique
Microprocessor and DSP core power supplies www.BDTIC.com/ADI adjustable lossless current-limit scheme utilizing external
Mobile communication base stations MOSFET sensing.
The ADP1821 operates over the –40°C to +125°C junction temperature range and is available in a 16-lead QSOP.
BIAS INPUT
5V TA = 25°C FREQUENCY = 300k Hz
10Ω D1 3.3V OUTPUT
POWER INPUT 2.5V TO 20V
VCC PVCC
1µF CIN1 CIN2 ADP1821 2.2µF 2.2µF 25V 25V
BST ×2
SHDN 0.47µF
DH M1
FREQ OUTPUT
SW 1.8V OUTPUT
SYNC 3.3kΩ
CSL COUT1 COUT2
PWGD M2 M3
DL 6.3V 2.5V 300Ω
PGND ×2 ×2
SS FB
GND 10n F
f SW = 300k Hz CIN1: MURATA, GRM31MR71E225k CIN2: SANYO, OSCON 20SP180M M1: IRLR7807Z COUT2: SANYO, OSCON 2R5SEPC820M M2, M3: IRFR3709Z L1: COILTRONICS, HC7-1R0 D1: VISHAY BAT54 LOAD CURRENT (A)
Figure 1. Typical Operating Circuit
Figure 2. Efficiency vs. Load Current, 5 V Input
Rev. C Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 781.329.4700 www.analog.com Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 ©2005–2007 Analog Devices, Inc. All rights reserved.
Page Summary Contents For ADP1821 Analog Devices Data Sheet Manual
Manual Details
| Brand | Analog Devices |
|---|---|
| Pages | 24 |
| File Size | 484.90 KB |
| Published | June 15, 2026 |
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Frequently Asked Questions
What is the input voltage range for the ADP1821 controller?
The device operates from a wide power-input voltage range spanning 1 V to 24 V.
How can I adjust the switching frequency?
It offers pin-selectable fixed switching frequencies of either 300 kHz or 600 kHz, and can be synchronized up to 1.2 MHz for specific applications.
Does the ADP1821 require external components like current sense resistors?
No current sense resistor is required because it utilizes an all N-channel MOSFET design, allowing regulation without one.
What specialized protections are included in this controller?
It features multiple protections, including soft start with reverse current protection, thermal overload, and undervoltage lockout functionality.