1A Driver Transistor Built-in Step-Down DC/DC Converters
The XC9223 series are synchronous step-down DC/DC converters with a 0.21Ω (TYP.) P-ch driver transistor and a synchronous 0.23Ω(TYP.) N-ch switching transistor built-in. A highly
efficient and stable current can be supplied up to 1.0A by reducing ON resistance of the built-in transistor. With a high switching frequency of 1MHz or 2MHz, a small inductor is selectable; therefore, the XC9223 series are ideally suited to applications with height limitation such as HDD or space-saving applications. Current limit value can be chosen either 1.2A (MIN.) when the LIM pin is high level, or 0.6A (MIN.) when the LIM pin is low level for using the power supply which current limit value differs such as USB or AC adapter.
With the MODE/SYNC pin, the XC9223 series provide mode selection of the fixed PWM control or automatically switching current limit PFM/PWM control. As for preventing unwanted switching noise, the XC9223 series can be synchronized with an external clock signal within the range of ± 25% toward an internal clock signal via the MODE/SYNC pin. For protection against heat damage of the ICs, the XC9223 series build in three protection functions: integral latch protection, thermal shutdown, and short-circuit protection. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel driver transistor is forced OFF when input voltage becomes 1.8V or lower. The XC9223B series’ detector function monitors the discretional voltage by external resistors.
Typical Application Circuit
|Input Voltage Range||2.5V～6.0V|
|Output Voltage Range||0.9V~VIN,(Can be set freely with 0.8V [±2%] of reference voltage by the external resistors.)|
|Oscillation Frequency||1MHz,2MHz (Accuracy ±15%)|
|Maximum Current Limit||0.6A(MIN.)0.9A(MAX.)LIM pin=“L”
|Control Methods||PWM/PFM externally switching,Synchronized with an external clock signal|
|Protection Circuits||Thermal shutdown,Integral latch method (over current limit),Short-circuit protection|
|Soft-Start||1ms (TYP.) inernally set|
|Voltage Detector||B type(with VD function),0.712V detect, N-ch open drain,D type(without VD function)|
|Package||MSOP-10||Number of Pins||10|
|Pcs/Reel||1,000||Package Size(mm)||4.9 x 3.0 x 1.16|
|Package||USP-10B||Number of Pins||10|
|Pcs/Reel||3,000||Package Size(mm)||2.6 x 2.9 x 0.6|
What is the soft-start function?
The function to soften the rise to prevent the inrush current.
What is the standby current?
The current that flows through the IC in the standby mode. The standby mode means the state where the IC has been turned off by the CE function.
What does the FB product mean?
An IC for which any output voltage can be set by the reference voltage of the FB pins and the external dividing resistor. The output voltage is determined by the RFB1 and RFB2 values, using the following formula: VOUT = Vref × (RFB1 + RFB2)/RFB2
How does UVLO (under voltage lockout) work?
This circuit forcibly turns off the driver transistor when VIN drops below the UVLO voltage. If the input voltage recovers to the value which is equal to the specified value or more, UVLO will be released to resume the switching operation. It is resumed by the soft-start function. The paused state by UVLO is not the shutdown. The pulse output is stopped, but the internal circuit is operating.