特点
5-Bit Programmable Output Voltage: 1.05V to 1.825V (VRM8.5)
No Sense Resistor Required
2% to 87% Duty Cycle at 200kHz
t
ON(MIN)
<= 100ns
Supports Active Voltage Positioning
True Current Mode Control
Stable with Ceramic C
OUT
Dual N-Channel MOSFET Synchronous Drive
Power Good Output Voltage Monitor
Wide V
IN
Range: 4V to 36V
±1% 0.8V Reference
Adjustable Current Limit
Adjustable Switching Frequency
Forced Continuous Control Pin
Programmable Soft-Start
Output Overvoltage Protection
Optional Short-Circuit Shutdown Timer
Micropower Shutdown: I
Q
< 30μA
Available in 28-Lead Narrow SSOP Package
典型应用
典型应用
描述
The LTC?3720 is a synchronous step-down switching regulator controller for CPU power. An output voltage between 1.05V and 1.825V is selected by a 5-bit code (Intel VRM8.5 VID specification). The controller uses a valley current control architecture to deliver very low duty cycles without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in V IN and V OUT .
Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling discontinuous mode operation when the main output is lightly loaded.
Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit level is also user programmable. Wide supply range allows operation from 4V to 36V at the input.