Dual, Interleaved, Step-Down

DC-to-DC Controller with Tracking

ADP1823

Rev. A

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FEATURES

Fixed-frequency operation: 300 kHz, 600 kHz, or

synchronized operation up to 1 MHz

Supply input range: 2.9 V to 20 V

Interleaved operation results in smaller, low cost input

capacitor

All-N-channel MOSFET design for low cost

±0.85% accuracy at 0

°C to 70°C

Soft start, thermal overload, current-limit protection

10 μA shutdown supply current

Internal linear regulator

Reverse current protection during soft start for handling

precharged outputs

Independent Power OK outputs

Voltage tracking for sequencing or DDR termination

Available in 5 mm × 5 mm, 32-lead LFCSP

APPLICATIONS

Telecommunications and networking systems

Medical imaging systems

Base station power

Set-top boxes

Printers

DDR termination

TYPICAL APPLICATION CIRCUIT

PV IN

GND

EN1

EN2

BST2

SW2

DH2

CSL2

DL2

PGND2

FB2

COMP2

FREQ

LDOSD

SYNC

TRK1

TRK2

VREG

BST1

DH1

SW1

CSL1

DL1

PGND1

FB1

COMP1

ADP1823

180µF

180µF

3900pF

390pF

IRFR3709Z

IRFR3709Z

IRLR7807Z

IRLR7807Z

1.2V,

6A

1.8V,

8A

390pF

3900pF

IN = 12V

560µF

560µF

2.2µH

2.2µH

1µF

0.47µF

0.47µF

4.53kΩ

4.53kΩ

1kΩ

2kΩ

2kΩ

2kΩ

2kΩ

2kΩ

Figure 1. Typical Application Circuit

GENERAL DESCRIPTION

The ADP1823 is a versatile, dual, interleaved, synchronous

PWM buck controller that generates two independent output

rails from an input of 2.9 V to 20 V. Each controller can be con-

figured 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 two channels operate 180° out of phase,

reducing stress on the input capacitor and allowing smaller, low

cost components. The ADP1823 is ideal for a wide range of

high power applications, such as DSP and processor core I/O

power, and general-purpose power in telecommunications,

medical imaging, PC, gaming, and industrial applications.

The ADP1823 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

also be synchronized to an external clock to achieve switching

frequencies between 300 kHz and 1 MHz. The ADP1823

includes soft start protection to prevent 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.

For applications requiring power supply sequencing, the

ADP1823 also provides tracking inputs that allow the output

voltages to track during startup, shutdown, and faults. This

feature can also be used to implement DDR memory bus

termination.

The ADP1823 is specified over the −40°C to +85°C ambient

temperature range, and is available in a 32-lead LFCSP package.