Nisshinbo Micro Devices NR1644

The NR1644 is a 2 A output voltage regulator with a minimum output voltage as low as 0.4 V. It incorporates advanced features such as a high ripple rejection ratio of 110 dB at 1 kHz and ultra-low output noise voltage of just 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 unique 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 just 90 mV at 1 A output current and 180 mV at 2 A, 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 minimizes PCB space usage and is available in an ultra-compact DFN2020-8-GA package measuring just 2.0 × 2.0 mm typ., with a maximum thickness of 0.8 mm.

Key features

• Input voltage range (absolute maximum rating): V_IN: V_SET + V_DO to V_BIAS (6.5 V), V_BIAS: V_SET + 1.5V (≥2.4V) to 5.5V (6.5 V)
• Output voltage range: 0.4 V to 1.5 V
• Output voltage accuracy: ±1.0% (T_a = 25 °C)
• Output current: 2.0 A
• Quiescent current (automatic mode alternative version): Typ. 75 μA
• Quiescent current (fast-mode fixed version): Typ. 1.0 mA
• Output Nnoise voltage (10 Hz to 100 kHz): Typ. 5 μVrms
• VIN pin ripple rejection: Typ. 110 dB (f = 1 kHz, I_OUT = 1 A), Typ. 50 dB (f = 1 MHz, I_OUT = 1 A)
• Dropout voltage: Typ. 90 mV (I_OUT = 1 A), Typ. 180 mV (I_OUT = 2 A)
• Protection functions: Thermal shutdown function, UVLO Function (VIN)

Applications

• Power supply for a CMOS image sensor
• Power supply for RF modules
• Power supply for high accuracy ADC, DAC
• Power supply for low-power consumption SoC, FPGA
• Power supply for a clock generation device such as VCO or PLL