High Voltage, 1.2 MHz/600 kHz, 800 mA,

Low Quiescent Current Buck Regulator

Data Sheet

ADP2370/ADP2371

Rev. A

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FEATURES

Input voltage range: 3.2 V to 15 V, output current: 800 mA

Quiescent current < 14 µA in power saving mode (PSM)

>90% efficiency

Force PWM pin (SYNC), 600 kHz/1.2 MHz frequency pin

(FSEL)

Fixed outputs: 0.8 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.0 V, 3.3 V, 5 V,

and adjustable option

100% duty cycle capability

Initial accuracy: ±1%

Low shutdown current: <1.2 µA

Quick output discharge (QOD) option

Synchronizable to an external clock

8-lead, 0.75 mm × 3 mm × 3 mm LFCSP (QFN) package

Supported by ADIsimPower design tool

APPLICATIONS

Portable and battery-powered equipment

Automatic meter readers (WSN)

Point of sales and transaction processing instruments

Medical instruments

Medium format display tablets and pads

TYPICAL APPLICATION CIRCUIT

ADP2370/

ADP2371

FSEL

EN

POWER GOOD

10µF

10µF

AGND

(EXPOSED PAD)

VIN

SYNC

ON

OFF

1.2MHz

600kHz

SW

PG

PGND

FB

1

2

3

4

8

7

6

5

Figure 1.

GENERAL DESCRIPTION

The ADP2370/ADP2371 are high efficiency, low quiescent current,

800 mA buck (step-down) dc-to-dc converters in small 8-lead,

3 mm × 3 mm LFCSP (QFN) packages. The total solution requires

only three tiny external components.

The buck regulator uses a proprietary high speed current mode,

constant frequency PWM control scheme for excellent stability

and transient response. The need for an external rectifier is elimi-

nated by using a high efficiency synchronous rectifier architecture.

To ensure the longest battery life in portable applications, the

ADP2370/ADP2371 employ a power saving variable frequency

mode that reduces the switching frequency under light load

conditions. The ADP2370/ADP2371 operate from input voltages

of 3.2 V to 15 V allowing the use of multiple alkaline/NiMH,

lithium cells, or other standard power sources.

The ADP2370/ADP2371 offer multiple options for setting the

operational frequency. The ADP2370/ADP2371 can be synchro-

nized to a 600 kHz to 1.2 MHz external clock or it can be forced

to operate at 600 kHz or 1.2 MHz via the FSEL pin. The ADP2370/

ADP2371 can be forced to operate in PWM mode (FPWM)

when noise considerations are more important than efficiency.

A power-good output is available to indicate when the output

voltage is below 92% of its nominal value.

The ADP2371 is identical to the ADP2370 except that the

ADP2371 includes the addition of an integrated switched

resistor, quick output discharge function (QOD) that auto-

matically discharges the output when the device is disabled.

Both devices include an internal power switch and a synchronous

rectifier for minimal external part count and high efficiency.

The ADP2370/ADP2371 also include internal soft start and

internal compensation for ease of use.

During a logic controlled shutdown, the input is disconnected

from the output and the regulator draws less than 1.2 μA from

the input source. Other key features include undervoltage lockout

to prevent deep battery discharge and soft start to prevent input

overcurrent at startup. Short-circuit protection and thermal over-

load protection circuits prevent damage under adverse conditions.

The ADP2370/ADP2371 each use one 0805 capacitor, one 1206

capacitor, and one 4 mm × 4 mm inductor. The total solution

to meet a variety of portable applications.