3-mode 1A LDO regulator from Nisshinbo

High-quality sensors, such as CMOS image sensors, and devices used in high-end audio and video equipment are known to be sensitive for noise. In particular, noise from power supplies can directly affect the performance of these devices, and noise suppression is essential to maximise performance.

The NR1641 series is a special solution to address this requirement, the LDO voltage regulator provides a powerful output current of 1A and in addition an low noise output of 3.7 μVrms and high ripple rejection of 80 dB (f = 10 kHz). The built-in "soft-start' function controls the slope of the output voltage during power up and is available in two different start-up rates. This function suppresses high inrush currents and simplifies regulation when there are supply input restrictions on devices in the downstream circuit.

Another special feature is the ability to adapt the performance of the LDO regulator to the actual use of the application; for example, if you're making a phone call or watching a video on a smartphone, you expect crystal-clear audio and video, but if it's in standby on your desk, you'd rather save power to extend battery life.

Therefore, three different operating modes are provided by the NR1641, an additional mode pin makes it possible to select operation in a fixed fast response mode or to switch automatically between fast response and low power mode depending on the output current demand. In this way it is possible to adjust for high performance or power saving features. The chip-enable pin controls the on / off mode to disable the regulator and reduce power consumption to a minimum. Additional product versions in WLCSP and high-wattage packages are currently under development.

Features of NR1641:

• Input Voltage Range (Maximum Rating): 1.7 V to 5.5 V (6.5 V)
• Output Voltage Range: 1.0 V to 5.0 V
• Output Voltage Accuracy: ± 1.0% (VSET ≥ 1.8 V, Ta = 25 °C)
• Output Current: 1.0 A
• Quiescent Current (VMODE = "Low"): Typ. 17 μA
• Quiescent Current (VMODE = "High"): Typ. 1.5 mA
• Output Noise Voltage (10 Hz to 100 kHz):
  • Typ. 3.7 μVrms (IOUT = 100 mA)
  • Typ. 20 μVrms (IOUT = 1 mA, VMODE = "Low")
• Ripple Rejection: Typ. 75 dB (f = 1 kHz, VSET = 2.8 V):
  • Typ. 80 dB (f = 10 kHz, VSET = 2.8 V)
  • Typ. 85 dB (f = 100 kHz, VSET = 2.8 V)
• Dropout Voltage:
  • Typ. 0.10 V (IOUT = 500 mA, VSET = 2.8 V, NR1641GY)
  • Typ. 0.20 V (IOUT = 1000 mA, VSET = 2.8 V, NR1641GY)
• Thermal Shutdown Function: Typ. 165 °C
• Slope of Output Voltage at Start-up: 200 μs/V or 500 μs/V
• Start-up Inrush Current Limit: Typ. 250 mA
• Protection: Foldback Current Limit Protection
• Fast / Low Power automatic mode function:
  • MODE pin "Low" Automatic alternating mode between fast response and low power
  • MODE pin "High" Fixed to fast response mode
• Ceramic Capacitors are recommended: CIN, COUT 10 μF or larger
• Package: DFN1616-6-GY (L1.6 x W1.6 x H0.4 mm)