The R1225 Series are low supply current CMOS-based PWM/VFM controlled step-down DC/DC controllers with an external output transistor. By simply using a power transistor, an inductor, a diode, and a capacitor as external components, a high-efficiency step-down DC/DC converter can be easily configured. The PWM/VFM alternative circuit automatically switches to VFM control in the smaller output current range and provides high efficiency even in the smaller output current range. The version with fixed PWM control is also available.
The latch type protection circuit embedded into the device latches the power MOS in the "OFF" state when the oscillator maximum duty cycle continues for a predetermined period of time. Protection time is adjustable by the capacity of an external capacitor of the DLY pin.
R1225 also includes an under-voltage lockout circuit (UVLO) that stops DC/DC operation and prevents malfunction when the supply voltage falls below the UVLO detector threshold and reduces supply current.
|Input Voltage Range (Maximum Rating)||2.3 V to 18.5 V (20.0 V)|
|Supply Current||Typ. 20 µA (R1225Nxx2A/B/J/K)
Typ. 30 µA (R1225Nxx2C)
Typ. 40 µA (R1225Nxx2D)
|Standby Current||Typ. 0.0 µA|
|Oscillator Frequency||180 kHz, 300 kHz, 500 kHz|
|Output Voltage Range||1.2 V to 6.0 V (0.1 V steps)|
|Output Voltage Accuracy||±2.0%|
|Temperature-Drift Coefficient of Output Voltage||Typ. ±100 ppm/°C|
|Soft Start Time||Typ. 10 ms|
|Latch-type Protection Function||Delay time for protection
Typ. 20 ms
R1225N332A Efficiency vs. Output Current
In the R1225 Series, the output voltage, and the optional function for the ICs can be selected at the user's request.
|Product Name||Package||Quantity per Reel|