Ultralow Profile, 500 mA, 6 MHz, Synchronous,

Step-Down, DC-to-DC Converters

ADP2126/ADP2127

Rev. A

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FEATURES

1.20 V and 1.26 V fixed output voltage options

Clock signal enable

Logic signal enable also available on certain models

6 MHz operating frequency

Spread spectrum frequency modulation to reduce EMI

500 mA continuous output current

Input voltage: 2.1 V to 5.5 V

0.3 μA (typical) shutdown supply current

Pin-selectable power-saving mode

Compatible with tiny multilayer inductors

Internal synchronous rectifier

Internal compensation

Internal soft start

Output-to-ground short-circuit protection

Current-limit protection

Undervoltage lockout

Thermal shutdown protection

0.330 mm height (maximum), 6-ball BUMPED_CHIP (ADP2126)

0.200 mm height (maximum), 6-pad EWLP (ADP2127)

APPLICATIONS

Mobile phones

Digital still/video cameras

Digital audio

Portable equipment

Camera modules

Image stabilization systems

TYPICAL APPLICATION CIRCUITS

A2

C2

B2

A1

B1

C1

VIN

GND

FB

SW

EXTCLK

MODE

2.2µF

2.2µF

INPUT

VOLTAGE

2.1V TO 5.5V

L

1.0µH

ADP2126

OUTPUT

VOLTAGE

1.20V OR 1.26V

OFF ON

OFF

ON

AUTO

PWM

OR

*LOGIC HIGH ENABLE IS ONLY AVAILABLE ON CERTAIN MODELS.

*

Figure 1. ADP2126 0.33 mm Maximum Height Solution

A2

C2

B2

A1

B1

C1

VIN

GND

FB

SW

EXTCLK

MODE

INPUT

VOLTAGE

2.1V TO 5.5V

L

0.56µH

ADP2127

OUTPUT

VOLTAGE

1.20V OR 1.26V

OFF ON

OFF

ON

AUTO

PWM

OR

2 × 1µF

2 × 1µF

*LOGIC HIGH ENABLE IS ONLY AVAILABLE ON CERTAIN MODELS.

*

Figure 2. ADP2127 0.22 mm Maximum Height Solution

GENERAL DESCRIPTION

The ADP2126/ADP2127 are high frequency, step-down, dc-to-

dc converters optimized for portable applications in which board

area and battery life are critical constraints. The fixed 6 MHz

operating frequency enables the use of tiny ceramic inductors

and capacitors and the regulators use spread spectrum frequency

modulation to reduce EMI. Additionally, synchronous rectification

improves efficiency and results in fewer external components.

At high load currents, the ADP2126/ADP2127 use a voltage

regulating pulse-width modulation (PWM) mode that maintains

a constant frequency with excellent stability and transient response.

Light load operation is determined by the state of the MODE pin.

In forced PWM mode, the converter continues operating in PWM

for light loads. Under light load conditions in auto mode, the

ADP2126/ADP2127 automatically enter a power-saving mode,

which uses pulse frequency modulation (PFM) to reduce the

effective switching frequency, thus ensuring the longest battery

life in portable applications.

The ADP2126/ADP2127 are enabled by a 6 MHz to 27 MHz

external clock signal applied to the EXTCLK pin. Certain models

can also be enabled with a logic high signal. When the external clock

is not switching and in a low logic state, the ADP2126/ADP2127

stop regulating and shut down to draw less than 0.3 μA (typical)

from the source.

The ADP2126/ADP2127 have an input voltage range of 2.1 V to

5.5 V, allowing the use of single Li+/Li polymer cell, three-cell

alkaline, NiMH cell, and other standard power sources. The

ADP2126/ADP2127 are internally compensated to minimize

external components and can source up to 500 mA. Other key

features, such as cycle-by-cycle peak current limit, soft start,

undervoltage lockout (UVLO), output-to-ground short-circuit

protection, and thermal shutdown provide protection for internal

and external circuit components.