New DC-DC controller IC meets low power demands

With the XC9252 designers can select fixed frequency PWM mode using the MODE/SYNC pin or alternatively PFM/PWM automatic switching can be used for improved efficiency during light loads. This guarantees maximum efficiency at higher output loads. The XC9252 includes Over Current and short circuit protection. The current limit threshold can be set externally with RSENSE and the designer can select either a Latch or Auto-restart configuration. 

The internal switching frequency can be externally set-up between 280kHz to 550kHz by connecting a resistor to the ROSC pin. Designers can also opt to synchronize the switching frequency of the DC-DC with an external CLK signal (within ±25% of the nominal frequency). 

With an external P-ch transistor, the XC9252 can generate a stable output from input Voltages as low as 3.0V. With a 0.8V reference voltage source (FB) the Output Voltage can be set freely from 1.5V using external resistors (RFB1, RFB2). There is also an optional Power-Good feature that allows the user to monitor the output state and the PG pin will go LOW if the FB drops below 90% of its nominal voltage.

The XC9252 series will be forced to stop operating by various protection circuits, such as a thermal shutdown circuit when the chip’s temperature reaches 150˚C and an Under Voltage Lock Out circuit when the input voltage decreases below 2.5V. Both of the above functions are implemented using hysteresis, and will allow the XC9252 to resume normal operation when the chip’s temperature drops below 125˚C and when the input voltage increases to 2.73V respectively.

With an operating temperature range of -40˚C ~+105˚C, the XC9252 is available in the USP-10B package for applications that require both a small form factor and a good amount of power dissipation and the TSSOP-16 package for handling even higher power dissipations. Additionally, fully populated EVBs can be provided upon request. 

Inexpensive ceramic capacitors can be used for the output load capacitor and the soft start time can be set as desired by adding an external capacitor to the SS pin.

Key Features:

• Input Voltage: 3.0V ~ 30V
• FB Voltage: 0.8V (±2%)
• Output Current: 3A ~
• Switching Frequency: Set Externally 280kHz ~ 550kHz
• Quiescent Current: 30uA @ 300kHz
• Max Duty Cycle: 100%
• Soft Start (externally set)
• Thermal Shutdown
• External CLK Sync
• Current Limit (with optional latch)
• Operating Ambient Temperature: -40°C ~ 105°C