The NR1644 is a 2A output voltage regulator with a minimum output voltage as low as 0.4V. It incorporates advanced features such as a high ripple rejection ratio of 110dB at 1kHz and ultra-low output noise voltage of 5µVrms. It makes it an ideal solution for power-sensitive applications, including CMOS image sensors, RF communication devices, high-precision ADC/DACs, and SoC/FPGA power supplies.
A special feature is its automatic mode selection feature, the NR1644 dynamically switches between fast response mode and low-power consumption mode based on the application’s output current requirements. The main benefit is that the enlarged current consumption in fast-mode only occurs when needed. This ensures optimal performance while maintaining power efficiency, when required, a dedicated fixed fast-mode version is also available.
What makes the NR1644 also different is its separated input terminal for the regulator driver and internal control circuitry. It results in a Bias pin to connect a supply voltage for the internal error amplifier, reference voltage circuit, and gate control voltage for the N-channel driver, the other VIN pin connects the N-channel driver. This innovative design allows the LDO to regulate very low input and output voltages, even beyond limitations for typical P-Channel driver LDOs.
With an ultra-low dropout voltage of 90mV at 1A output current and 180mV at 2A, the NR1644 ensures minimal power loss, making it particularly useful for battery-operated and IoT devices where power efficiency is crucial. It also features multiple built-in protection functions, including thermal shutdown, undervoltage lockout (UVLO), soft-start control, and a discharge function, ensuring reliable and safe operation under varying conditions. An additional N-Channel open drain output provides a power good signal indicating that all protection circuits are in the safe mode.
The NR1644 minimises PCB space usage and is available in an ultra-compact DFN2020-8-GA package measuring 2.0 x 2.0mm typ., with a maximum thickness of 0.8mm. For rapid prototyping and development, evaluation boards featuring the device are available.
NR1644 Specifications:
- Operating junction temperature range: -40°C to 125°C
- Input voltage range (absolute maximum rating):
- VIN: VSET + VDO to VBIAS (6.5V),
- VBIAS: VSET + 1.5V (≥2.4V) to 5.5V (6.5V)
- Output voltage range: 0.4V to 1.5V
- Output voltage accuracy: ±1.0% (Ta = 25°C)
- Output current: 2.0A
- Quiescent current (automatic mode alternative version): typ. 75μA
- Quiescent current (fast-mode fixed version): typ. 1.0mA
- Output noise voltage (10Hz to 100kHz): typ. 5μVrms
- VIN pin ripple rejection: typ. 110dB (f = 1kHz, IOUT = 1A), typ. 50dB (f = 1MHz, IOUT = 1A)
- Dropout voltage: typ. 90mV (IOUT = 1A), typ. 180mV (IOUT = 2A)
- Ceramic capacitors are recommended: COUT ≥ 10μF, CIN ≥ 4.7μF, CNR = 0.1μF to 2.2μF
- Protection functions: thermal shutdown function, UVLO function (VIN)
- Miscellaneous functions: soft-start function, discharge function, power-good function
- Package NR1644GA: DFN2020-8-GA (2.0 x 2.0mm typ., t = 0.8mm max.)
- Datasheet NR1644: consumer version
