DC-DC Controller. CN5120 Datasheet
4.5V to 32V Input Current Mode Boost DC-DC Controller
The CN5120 is a current mode fixed-frequency
PWM controller for both flyback and step-up
DC-DC converters. The device operates from an
input supply between 4.5V and 32V and provides to
drive an external N-channel MOSFET.
The CN5120 contains all the necessary building
blocks including a bandgap reference, a 330KHz
oscillator, current-mode control circuitry, chip
shutdown block, softstart block and gate driver, etc.
Current mode control provides improved transient
response and simplified loop compensation. On-chip
soft start reduces the inrush current on power up. The
other features include chip shutdown, over voltage
protection, built-in 5V regulator and slope
The CN5120 is available in 10-pin SSOP package.
TFT-LCD Bias Supplies
XDSL Power Supplies
Digital Video Cameras
Peak Current Mode DC-DC Boost/ Flyback
4.5V to 32V Input Range
330kHz Switching Frequency
±2% Output Voltage Accuracy
Cycle-by-Cycle Peak Inductor Current Limit
On-Chip Slope Compensation
Built-in 5V regulator
Low Shutdown Current
Operating Temperature Range:
－40℃ to 85℃
Available in 10-pin SSOP package.
Lead-free, Rohs-compliant and Halogen-free
Typical Application Circuit
Figure 1 Typical Application Circuit
1 NC No Connection.
Feedback Pin. The output voltage is feedback to this pin. Generally this pin is
connected to the external resistor divider to sense the output voltage.
Compensation Pin. Connect the compensation network between COMP pin and
4 NC No Connection.
Shutdown Input Pin. Pulling this pin high, places the part into a shutdown mode.
Shutdown mode is characterized by a very low quiescent current. In shutdown mode,
all the functionality of all blocks is disabled and the on-chip 5V regulator is also
shutdown. Pulling this pin low places the part into normal operation mode.
Input Supply Voltage. Positive terminal of input supply. The input voltage range is
4.5V to 32V. Connect a local bypass capacitor from this pin to GND.
5V Regulator output. A bypass capacitor of 4.7uF should be connected from this pin
to GND. If the input voltage is less than 5.5V, the voltage at VCC pin may be less
Gate Drive Pin. Gate drive for the external N-channel MOSFET. Connect this pin to
the gate of external N-channel MOSFET.
Ground. Negative terminal of input supply.
Inductor Current Sense Pin. The inductor current is sensed at CS pin on the
cycle-by-cycle basis for both the current mode control and over current protection.
Absolute Maximum Ratings
VIN Terminal Voltage…………..…－0.3V to 36V
Other Terminals Voltage…………..－0.3V to 6.5V
Operating Temperature…..............－40℃ to 85℃
Thermal Resistance(Junction to Case) .....200℃/W
Maximum Junction Temperature……………150℃
Storage Temperature……….......－65℃ to 150℃
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. These are stress ratings only, and functional operation of the device at these or any other
conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure
to absolute maximum rating conditions for extended periods may affect device reliability.
(VIN = 12V, TA＝－40°C to +85°C, Typical values are at TA＝+25°C, unless otherwise noted)
Input Supply Voltage
Input Supply Current
Maximum Duty Cycle
Minimum On Time
Over current Threshold
FB Pin Bias Current
Input Voltage High
Input Voltage Low
SHDN Bias Current
Measured at CS pin
IVCC＝0.1mA to 4mA,
VIN＝5.5V to 32V
IVCC＝0.1mA to 4mA，
VIN＝6V to 32V, IVCC＝3mA
VCC＝0 to 4.5V, COUT＝4.7uF