R1172x Series

Super Low On Resistance / Low Voltage 1A LDO for Automotive Applications


Data Sheet

Data Sheet

The R1172x is a CMOS-based positive voltage regulator IC that is specifically designed for automotive applications. The R1172x has features of super low dropout, 1A output current capability. Even the output voltage is set at 1.5V, on resistance of internal FET is typically 0.32Ω. Therefore, applications that require a large current at small dropout are suitable for the R1172x. Low input voltage is acceptable and low output voltage can be set. The minimum input voltage is 1.4V, and the lowest set output voltage is 0.8V. Each of these ICs consists of a voltage reference unit, an error amplifier, resistor net for setting output voltage, a current limit circuit at over-current, a chip enable circuit, a thermal-shutdown circuit, and so on. A stand-by mode with ultra low consumption current can be realized with the chip enable pin. The output voltage of R1172 is fixed in the IC.
Since the packages for this IC are SOT-23-5, SOT-89-5, and HSOP-6J with high power dissipation, high density mounting of the ICs on boards is possible.


Input Voltage Range (Maximum Rating) 1.4V to 6.0V (6.5V)
Output Current 1A
Supply Current Typ. 60µA
Standby Current Typ. 0.1µA
Output Voltage 0.8V to 5.0V (0.1V step)
(For other voltages, refer to Data Sheet).
Dropout Voltage Typ. 0.32V (VSET=1.5V, IOUT=1A)
Typ. 0.18V (VSET=2.8V, IOUT=1A)
Ripple Rejection Typ. 70dB (VSET=2.8V)
Output Voltage Accuracy ±2.0%
Output Voltage Temperature Coefficient Typ. ±100ppm/°C
Line Regulation Typ. 0.05%/V
Load Regulation Typ. 15mV at IOUT=300mA, Typ. 50mV at IOUT=1A
Output Noise 30µVrms
Packages SOT-23-5, SOT-89-5, HSOP-6J
Built-in Inrush current limit circuit Typ. 500mA
Built-in Fold-Back Protection Circuit Typ. 250mA (Current at short mode)
Built-in Thermal Shutdown Circuit Thermal Shutdown Temperature: Typ. 150°C
Released Temperature: Typ. 120°C
Built-in Auto Discharge Function R1172xxxxD
Output capacitors CIN=COUT=Tantalum 4.7µF (VOUT < 1.0V)
CIN=COUT=Ceramic 4.7µF (VOUT≥1.0V)


  • Power source for car accessories including car audio equipment, car navigation system, and ETC system.

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Data Sheet Package Quality Assurance Data Suffix Composition & Content*1
R1172x Series
SOT-23-5 Contact us*2 -HE Sn (Sn: 100%)
SOT-89-5 Contact us*2 -HE Sn (Sn: 100%)
Reliability -AE
HSOP-6J Reliability -AE Sn (Sn: 100%)
  • *1The composition of the product cannot be specified.
  • *2The reliability information is not listed for devices above rank2. Please contact Ricoh sales representatives for further informations.

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