Datasheet LTC3374A (Analog Devices) - 10

LTC3374A
pin FuncTions (QFN/TSSOP) FB1 (Pin 1/Pin 4):
Feedback Pin for Buck Regulator 1.
FB4 (Pin 12/Pin 15):
Feedback Pin for Buck Regulator 4. Program the output voltage and close the control loop Program the output voltage and close the control loop by by connecting this pin to the middle node of a resistor connecting this pin to the middle node of a resistor divider divider between the output and ground. between the output and ground. To combine buck regula-
V
tor 4 with buck regulator 3 for higher current, connect FB4
IN1 (Pin 2/Pin 5):
Buck Regulator 1 Input Supply. Bypass to GND with a 10µF or larger ceramic capacitor. to VIN4. Up to four converters may be combined in this way.
SW1 (Pin 3/Pin 6):
Switch Node for Buck Regulator 1.
EN4 (Pin 13/Pin 16):
Enable Input for Buck Regulator 4. Connect an external inductor to this pin. Active high. Do not float.
SW2 (Pin 4/Pin 7):
Switch Node for Buck Regulator 2.
EN3 (Pin 14/Pin 17):
Enable Input for Buck Regulator 3. Connect an external inductor to this pin. Active high. Do not float.
V PGOOD_ALL (Pin 15/Pin 18):
PGOOD Status Pin. Open-
IN2 (Pin 5/Pin 8):
Buck Regulator 2 Input Supply. Bypass to GND with a 10µF or larger ceramic capacitor. Short to drain output. When the regulated output voltage of V any enabled switching regulator falls below its PGOOD IN1 when buck regulator 2 is combined with buck regula- tor 1 for higher current. threshold or rises above its overvoltage threshold, this pin is driven LOW. When all buck regulators are disabled
FB2 (Pin 6/Pin 9):
Feedback Pin for Buck Regulator 2. PGOOD_ALL is driven LOW. Program the output voltage and close the control loop by connecting this pin to the middle node of a resistor divider
SYNC (Pin 16/Pin 19):
Oscillator Synchronization Pin. between the output and ground. To combine buck regulator Driving SYNC with an external clock signal synchronizes 2 with buck regulator 1 for higher current, connect FB2 to all switchers to the applied frequency. The slope com- V pensation is automatically adapted to the external clock IN2. Up to four converters may be combined in this way. frequency. The absence of an external clock signal enables
FB3 (Pin 7/Pin 10):
Feedback Pin for Buck Regulator 3. the frequency programmed by the RT pin. SYNC should Program the output voltage and close the control loop by be held at ground if not used. Do not float. connecting this pin to the middle node of a resistor divider between the output and ground. To combine buck regula-
RT (Pin 17/Pin 20):
Oscillator Frequency Pin. Connect tor 3 with buck regulator 2 for higher current, connect FB3 a resistor from RT to ground to program the switching to V frequency. Tie RT to VCC to use the default internal 2MHz IN3. Up to four converters may be combined in this way. oscillator. Do not float.
VIN3 (Pin 8/Pin 11):
Buck Regulator 3 Input Supply. Bypass to GND with a 10µF or larger ceramic capacitor. Short to
EN6 (Pin 18/Pin 21):
Enable Input for Buck Regulator 6. V Active high. Do not float. IN2 when buck regulator 3 is combined with buck regula- tor 2 for higher current.
EN5 (Pin 19/Pin 22):
Enable Input for Buck Regulator 5.
SW3 (Pin 9/Pin 12):
Switch Node for Buck Regulator 3. Active high. Do not float. Connect an external inductor to this pin.
FB5 (Pin 20/Pin 23):
Feedback Pin for Buck Regulator 5.
SW4 (Pin 10/Pin 13):
Switch Node for Buck Regulator 4. Program the output voltage and close the control loop by Connect an external inductor to this pin. connecting this pin to the middle node of a resistor divider between the output and ground. To combine buck regula-
VIN4 (Pin 11/Pin 14):
Buck Regulator 4 Input Supply. tor 5 with buck regulator 4 for higher current, connect FB5 Bypass to GND with a 10µF or larger ceramic capacitor. to VIN5. Up to four converters may be combined in this way. Short to VIN3 when buck regulator 4 is combined with buck regulator 3 for higher current. 3374af 10 For more information www.linear.com/LTC3374A Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information (http://www.linear.com/product/LTC3374A#orderinfo) Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Buck Switching Regulators Buck Regulators with Combined Power Stages Power Failure Reporting Via PGOOD_ALL Pin Temperature Monitoring and Overtemperature Protection Programming the Operating Frequency Applications Information Buck Switching Regulator Output Voltage and Feedback Network Input and Output Decoupling Capacitor Selection Combined Buck Regulators Buck Regulators PCB Considerations Package Description Typical Application Related Parts