(ADP2370 / ADP2371) Low Quiescent Current Buck Regulator
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High Voltage, 1.2 MHz/600 kHz, 800 mA,
Low Quiescent Current Buck Regulator
Input voltage range: 3.2 V to 15 V, output current: 800 mA
Quiescent current < 14 µA in power saving mode (PSM)
Force PWM pin (SYNC), 600 kHz/1.2 MHz frequency pin
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
Portable and battery-powered equipment
Automatic meter readers (WSN)
Point of sales and transaction processing instruments
Medium format display tablets and pads
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.
VIN = 6V
TYPICAL APPLICATION CIRCUIT
VOUT = 3.3V
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
size is about 53 mm2 resulting in a very small footprint solution
to meet a variety of portable applications.
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