R1245x SeriesAEC-Q100 Compliant *Only R1245S

1.2A, 30V Step Down DC/DC converter for Automotive Applications


Data Sheet

Data Sheet

The R1245x is a Step-down DC/DC converter with internal N-channel high side Tr. That is developed with CMOS process technology. The ON resistance of the built-in high-side transistor is 0.35 Ω and the R1245x can provide the maximum 1.2 A output current. Each of the ICs consists of an oscillator, a PWM control circuit, a voltage reference unit, an error amplifier, a phase compensation circuit, a slope compensation circuit, a soft-start circuit, protection circuits, an internal voltage regulator, and a switch for bootstrap circuit. The ICs can make up a step-down DC/DC converter with an inductor, resistors, a diode, and capacitors.
The R1245x is a current mode operating type DC/DC converter without an external current sense resistor, and realizes fast response and high efficiency. As an output capacitor, a ceramic type capacitor can be used with the R1245x. The options of the internal oscillator frequency are preset at 330 kHz for version A and B, 500 kHz for version C and D, 1000 kHz for version E and F, 2400 kHz for version G and H.
As for protection, an Lx peak current limit circuit cycle by cycle, a thermal shutdown function and an under voltage lockout (UVLO) function are built in. Furthermore, there are two types for short protection, for A/C/E/G version, a latch protection function which makes the output latch off if the output voltage keeps lower than the set output voltage for a certain time after detecting current limit is built in, for B/D/F/H version, a fold-back protection function which changes the oscillator frequency slower after detecting short circuit or equivalent.
As for the packages of the R1245x, HSOP-8E and DFN2020-8 are available.


Input Voltage Range (Maximum Rating) 4.5V to 30V (32V)
Operating Temperature −40°C to 105°C
Internal N-channel MOSFET Driver RON=0.35Ω Typ.
Adjustable Output Voltage with External Resistor 0.8V or more
Feedback Voltage and Tolerance 0.8V±1.0%
Peak Current Limit Typ. 2.0A
UVLO Function Released Voltage Typ. 4.0V
Operating Frequency 330kHz (A/B version), 500kHz (C/D version),
1000kHz (E/F version), 2400kHz (G/H version)
Fold-back Protected Frequency 170kHz (B/D version), 250kHz (F version), 400kHz (H version)
Latch Protection Delay Time Typ. 4ms for A/C/E/G version
Built-in Thermal Shutdown Circuit Typ. 160°C
Ceramic Capacitors Recommended for Input and Output
Stand-by Current Typ. 0μA
Packages HSOP-8E, DFN2020-8
AEC-Q100 Compliant Product Package Type HSOP-8E


  • Power source for car accessories including car audio equipment, car navigation system, and ETC system.
  • Power source for control units including EV inverter and charge control.

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Data Sheet Package Quality Assurance Data Suffix Composition & Content*1
R1245x Series
HSOP-8E Contact us*2 -JE Sn (Sn: 100%)
Reliability -AE
DFN2020-8 Reliability -AE Ni-Pd-Au (-)
  • *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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