SC1470
SC1470 is Synchronous Buck Power Supply Controller manufactured by SEMTECH.
Description
The SC1470 is a single output, constant on-time synchronous-buck, pseudo fixed frequency, PWM controller intended for use in notebook puters and other battery operated portable devices. Features include high efficiency and fast dynamic response with no minimum on time. The excellent transient response means that SC1470 based solutions will require less output capacitance than peting fixed frequency converters.
Features
Constant on-time for fast dynamic response Programmable VOUT range = 0.5
- VCCA VIN range = 1.8V
- 25V DC current sense using low-side RDS(ON) Sensing or RSENSE in source of low-side MOSFET for greater accuracy Resistor programmable frequency Cycle-by-Cycle current limit Digital soft-start bined EN and PSAVE functions Over-voltage/under-voltage fault protection and PGOOD output 5u A typical shutdown current Low quiescent power dissipation 14 Lead TSSOP package Industrial temperature range 1% Internal reference Integrated gate drivers with soft switching Efficiency > 90% Notebook puters CPU I/O supplies Handheld terminals and PDAs LCD monitors Network power supplies
The frequency is constant until a step in load or line voltage occurs, at which time the pulse density and frequency will increase or decrease to counter the change in output or input voltage. After the transient event, the controller frequency will return to steady state operation. At light loads, Power-Save Mode enables the SC1470 to skip PWM pulses for better efficiency.
The output voltage can be adjusted from 0.5V to VCCA. The integrated gate drivers feature adaptive shoot- through protection and soft switching. Additional Features include cycle-by-cycle current limit, digital soft-start, overvoltage and under-voltage protection, and a PGOOD output.
Applications
Typical Application Circuit
1.8V
- 25V
+5V + R1 C1 + C2
D1 R2 +5V +5V R3 1 2 3 4 5 6 7 C6 SC1470 Q2 U1 BST EN/PSV DH TON LX VOUT ILIM VCCA VDDP FBK PGOOD DL...
