The ADP2140 contains a high efficiency, low quiescent current, 600 mA
Step-down DC-DC converterand a 300 mA LDO in a 10-lead, 3 mm × 3 mm small LFCSP package. The entire solution requires only four small external components.
The buck regulator uses a proprietary high-speed current-mode, constant-frequency pulse-width modulation (PWM) control scheme with excellent stability and transient response. To ensure maximum battery life in portable applications, the device offers a variable frequency power-down mode that reduces the switching frequency at small loads.
The LDO is a low quiescent current, low dropout linear regulator that operates in separate power mode with input voltages (VIN2) as low as 1.65 V. The low input voltage allows the LDO to be powered from the output of a buck regulator, improving efficiency and reducing power consumption. The ADP2140 operates from an input voltage of 2.3 V to 5.5 V and can be powered by a single Li+/Li− polymer battery, multiple alkaline/NiMH batteries, PCMCIA, and other standard supplies.
To minimize external component count and improve efficiency, all versions include built-in power switches and synchronous rectifiers. The ADP2140 includes a power good pin, soft-start, and internal compensation. There are many power sequencing schemes available that the user can select with two enable inputs. In automatic sequencing mode, the highest voltage output is enabled on the rising edge of EN1. During a logic-controlled shutdown, the input is disconnected from the output, drawing less than 100 nA from the input source. Other important features include: undervoltage lockout, which prevents deep battery discharge; Soft start to prevent input current overshoot at startup; and short-circuit protection and thermal overload protection circuitry to prevent damage under adverse conditions.
When the ADP2140 uses two 0603 capacitors, one 0402 capacitor, one 0402 resistor, and one 0805 inductor, the total solution area is approximately 90 mm2, which is the smallest size solution for a variety of portable applications.
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- mobile phone
- Personal media player
- Digital cameras and audio equipment
- Portable and battery-powered devices
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Advantages and features
- Input voltage range: 2.3 V to 5.5 V
- LDO input (VIN2): 1.65 V to 5.5 V
- Buck output voltage range: 1.0 V to 3.3 V
- LDO output voltage range: 0.8 V to 3.3 V
- Buck output current: 600 mA
- LDO output current: 300 mA
- LDO quiescent current: 22 μA22 μA (no load)
- Buck converter quiescent current: 20 μA (PSM mode)
- Low shutdown current: less than 0.3 µA
- Low LDO dropout voltage: 110 mV at 300 mA load
- High LDO PSRR
65 dB （10 kHz，VOUT2 = 1.2 V） 55 dB （100 kHz， VOUT2 = 1.2 V）
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