3 A, 1.2 MHz/600 kHz High Efficiency

Synchronous Step-Down DC-to-DC Converter

ADP2118

Rev. 0

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FEATURES

3 A continuous output current

75 mΩ and 40 mΩ integrated FET

±1.5% output accuracy

Input voltage range from 2.3 V to 5.5 V

600 kHz or 1.2 MHz fixed switching frequency

Synchronizable between 600 kHz and 1.4 MHz

Selectable PWM or PFM mode operation

Current mode architecture

Precision enable input

Power good output

Voltage tracking input

Integrated soft start

Internal compensation

Starts up into a precharged output

UVLO, OVP, OCP, and thermal shutdown

Available in 16-lead 4mm × 4mm LFCSP_WQ package

APPLICATIONS

DSP/FPGA/ASIC core power

Telecommunication/networking equipment

PDAs and palmtop computers

Audio/video consumer electronics

GENERAL DESCRIPTION

The ADP2118 is a low quiescent current, synchronous, step-down,

dc-to-dc converter in a compact 4mm × 4mm LFCSP_WQ

package. It uses a current mode, constant frequency pulse-width

modulation (PWM) control scheme for excellent stability and

transient response. Under light loads, the ADP2118 can be

configured to operate in pulse frequency modulation (PFM)

mode that reduces switching frequency to save power.

The ADP2118 runs from input voltages of 2.3 V to 5.5 V. The

output voltage of the ADP2118ACPZ-R7 is adjustable from

available in preset output voltage options of 3.3 V, 2.5 V, 1.8 V,

1.5 V, 1.2 V, and 1.0 V. The ADP2118 requires minimal external

parts and provides a high efficiency solution with its integrated

power switch, synchronous rectifier, and internal compensation.

The IC draws less than 3 μA from the input source when it is

disabled. Other key features include undervoltage lockout

(UVLO), integrated soft start to limit inrush current at startup,

overvoltage protection (OVP), overcurrent protection (OCP),

and thermal shutdown (TSD).

10kΩ

2.21kΩ

R2

10kΩ

R1

10Ω

SYNC/MODE

FREQ

TRK

FB

PVIN

ADP2118

SW

SW

SW

1

2

3

4

12

11

10

9

100µF

X5R,

6.3V

100µF

X5R,

6.3V

C1

0.1µF

5V

3.3V

3A

L

1µH

16

15

14

13

5

6

7

8

Figure 1. Typical Applications Circuit

0

10

20

30

40

50

60

70

80

90

100

0.01

0.1

1

10

OUTPUT CURRENT (A)

PFM OPERATION

FPWM OPERATION

Figure 2. Efficiency vs. Output Current