The ADP2370/ADP2371 are high efficiency, low quiescent current, 800 mA
Step-down DC-DC converterin a small 8-pin, 3 mm × 3 mm LFCSP (QFN) package. The entire solution requires only three small external components.
The buck regulator uses a proprietary high-speed current-mode, constant-frequency PWM control scheme with excellent stability and transient response. These devices have a built-in high-efficiency synchronous rectifier structure, eliminating the need for an external rectifier.
To ensure maximum battery life in portable applications, the ADP2370/ADP2371 offer a variable frequency power-down mode that reduces the switching frequency under light load conditions. These devices operate from an input voltage of 3.2 V to 15 V, allowing them to be powered from multiple alkaline/NiMH batteries, lithium batteries, or other standard power sources.
The ADP2370/ADP2371 offer several options for setting the operating frequency. These devices can be synchronized to an external clock from 600 kHz to 1.2 MHz or forced to operate at 600 kHz or 1.2 MHz through the FSEL pin. When noise is more important than efficiency, the ADP2370/ADP2371 can be forced to operate in PWM mode (FPWM).
These devices provide a power good output to indicate when the output voltage falls below 92% of its nominal value.
The only difference between the ADP2371 and the ADP2370 is that the ADP2371 has an integrated switch resistor, the fast output discharge function (QOD), which automatically discharges the output when the device is disabled.
To minimize external component count and improve efficiency, both devices include power switches and synchronous rectifiers. For ease of use, the ADP2370/ADP2371 also include internal soft-start and internal compensation.
During logic-controlled shutdown, the input and output are disconnected and the regulator draws less than 1.2 μA from the input source. Other important features include: undervoltage lockout, which prevents deep battery discharge; and soft start to prevent input overcurrent at startup. Short-circuit protection and thermal overload protection circuitry prevent damage under adverse conditions.
The ADP2370/ADP2371 each use a 0805 capacitor, a 1206 capacitor, and a 4 mm × 4 mm inductor. The overall solution size is extremely small, approx. 53 mm2for a variety of portable applications.
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- Portable and battery-powered devices
- Automatic Meter Reader (WSN)
- POS devices and transaction processing equipment
- Medical instruments
- Medium format tablet
Advantages and features
- Input voltage range: 3.2 V to 15 V, output current: 800 mA
- Quiescent current is less than 14 μA in power-down mode (PSM).
- Efficiency: >90%
- 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 options
- Duty cycle capability: 100%
- Initial accuracy: ±1%
- Low shutdown current:
- Fast Output Discharge (QOD) Option (ADP2371)
- Can be synchronized to an external clock
- 8-pin, 0.75 mm × 3 mm × 3mm LFCSP (QFN) packages
- ADIsimPower design tool support
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