ADP1822 Analog Devices Data Sheet

PWM, Step-Down DC-to-DC Controller with Margining and Tracking

ADP1822 FEATURES The ADP1822 regulated output can track another power supply

and can be dynamically adjusted up or down with the controller’s

Wide power input voltage range: 1 V to 24 V

margining-control inputs, making it ideal for high reliability

Chip supply voltage range: 3.7 V to 5.5 V

applications. It is well suited for a wide range of high power

Wide output voltage range: 0.6 V to 85% of input voltage

applications, such as DSP power and processor core power in

1% accuracy, 0.6 V reference voltage

telecommunications, medical imaging, high performance

Output voltage margining control

servers, and industrial applications. It operates from a 3.7 V to

Output voltage tracking

5.5 V supply with power input voltage ranging from 1.0 V to 24 V.

All N-channel MOSFET 300 k Hz, 600 k Hz, or up to 1.2 MHz synchronized frequency The ADP1822 can operate at any frequency between 300 k Hz No current sense resistor required and 1.2 MHz, either by synchronizing with an external source Power-good output or an internally generated, logic-controlled clock of 300 k Hz or Programmable soft start with reverse current protection 600 k Hz. It includes an adjustable soft start to allow sequencing Current-limit protection and quick power-up while preventing input inrush current. Output Thermal overload protection reverse-current protection at startup prevents excessive output Overvoltage protection voltage excursions. The adjustable, virtually lossless current- Undervoltage lockout limit scheme reduces external part count and improves efficiency. 1 μA shutdown supply current The ADP1822 operates over the −40°C to +125°C junction

EF FI IE temperature range and is available in a 24-lead QSOP package. Small, 24-lead QSOP package

APPLICATIONS 97 Telecommunications and networking systems

3.3V OUTPUT

High performance servers

Medical imaging systems www.BDTIC.com/ADI

DSP core power supplies Microprocessor core power supplies

1.8V OUTPUT

Mobile communication base stations Distributed power

GENERAL DESCRIPTION The ADP1822 is a versatile and inexpensive synchronous voltage- mode PWM step-down controller. It drives an all N-channel power stage to regulate an output voltage as low as 0.6 V.

LOAD CURRENT (A)

Figure 1. Efficiency vs. Load Current, 5 V Input

CMOSH-3

BIAS INPUT POWER INPUT

5V 1- 2.25V TO 24V

1µF VCC BST

IRF3711

ADP1822 DH

SW OUTPUT

SHDN 6.18kΩ

CSL 1.8V, 15A

IRF3711 4V

SYNC 2.2p F

PGND 20kΩ

MSEL 1n F 10kΩ

COMP MDN

80.6kΩ SS MUP

AGND DGND

TRACKING SIGNAL INPUT

Figure 2. Typical Operating Circuit

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