The R1243x series is a CMOS-based Step-Down DC/DC Converter with internal Nch high side Tr. (0.175Ω), which can provide the maximum 2A output current. The IC consists of an Oscillator, a PWM control circuit, a Reference Voltage unit, an Error amplifier, phase compensation circuits, a slope circuit, a soft start circuit, protection circuits, internal voltage regulators, and a switch for bootstrap circuit. The R1243x Series can make up a Step-Down DC/DC Converter with the following external components: an inductor, resistors, a diode, and capacitors. The R1243x series are current mode operating type DC/DC converter which does not require external current sense resistor, and it works high speed response time, high efficiency and compatible with ceramic capacitors. There are two types for the oscillator frequency. A/B version's frequency is fixed 1000kHz, and C/D version's frequency is fixed 330kHz.As a protection function, it has cycle by cycle peak current limit function, short protection function, thermal shutdown function and UVLO. There are two types for short protection, A/C version has latch protection function with 2ms delay time, and B/D version has fold back protection function that keep operating at short condition with lower operating frequency and limiting the Lx current. The R1243 Series has the built-in soft start time (Typ. 0.4ms). In addition to this, the soft start time is adjustable by controller's I/O port.
The Ricoh R1243x Series is a CMOS-based Step-Down DC/DC converter designed to provide a maximum output current of 2A. The IC integrates an oscillator, PVM control circuit, reference voltage unit, error amplifier, phase compensation circuits, slope circuit, soft start circuit, and protection circuits, including an internal Nch high-side MOSFET driver. It operates in current mode and does not require an external current sense resistor, offering high-speed response and compatibility with ceramic capacitors.
| Operating Voltage | 4.5V ~ 30V |
|---|---|
| Output Voltage Range | 0.8V ~ 18V |
| Feedback Voltage Accuracy | 0.5V with 1.4% accuracy |
| Internal Nch MOSFET Driver Resistance | Typ. 175mQ |
| Operating Frequency (Ver.A/B) | 1000KHz |
| Operating Frequency (Ver.C/D) | 330kKHz |
| Short protection delay time (Latch) | Typ. 2ms |
| Internal Soft Start Time | Typ. 0.4ms |
| Package Types | HSOP-8E, DFN(PLP)2527-10 |
The A/B version operates at a fixed frequency of 1000KHz, while the C/D version operates at a fixed frequency of 330kHz.
No, it is a current mode operating type DC/DC converter which does not require an external current sense resistor.
The series includes cycle by cycle peak current limit, short protection, thermal shutdown, and UVLO functions.
The ICs are available in HSOP-8E and DFN(PLP)2527-10 packages.