Datasheet LTC1702A (Analog Devices) - 7

LTC1702A
TEST CIRCUIT Test Circuit 1
5V + 0.1µF IBOOST1 ICC IPVCC IBOOST2 100µF VCC PVCC BOOST1 BOOST2 fOSC TG1 TG2 MEASURED 5V BG1 BG2 SW1 SW2 CL CL CL CL 5V 10k IMAX1 IMAX2 FCB LTC1702A 10k V PGOOD1 PGOOD2 PGOOD1 VPGOOD2 FAULT VFAULT RUN/SS1 RUN/SS2 2k 2k COMP1 COMP2 V FB1 FB2 FB1 VFB2 GND PGND 1702A TC
U U W U APPLICATIONS INFORMATION OVERVIEW
controllers allow, improving stability and maximizing tran- sient response. The 800mV internal reference allows The LTC1702A is a dual, step-down (buck), voltage mode regulated output voltages as low as 800mV without exter- feedback switching regulator controller. It is designed to nal level shifting amplifiers. be used in a synchronous switching architecture with two external N-channel MOSFETs per channel. It is intended to The LTC1702A’s synchronous switching logic transitions operate from a low voltage input supply (7V maximum) automatically into Burst Mode operation, maximizing effi- and provide a high power, high efficiency, precisely regu- ciency with light loads. Onboard power-good and over- lated output voltage. Several features make it particularly voltage (OV) fault flags indicate when the output is in suited for microprocessor supply regulation. Output regu- regulation or an OV fault has occurred. The OV flag can be lation is extremely tight, with DC line and load regulation set to latch the device off when an OV fault has occurred, and initial accuracy better than 1%, and total regulation or to automatically resume operation when the fault is including transient response inside of 3% with a properly removed. designed circuit. The 550kHz switching frequency allows The LTC1702A takes a low input voltage and generates the use of physically small, low value external components two lower output voltages at very high currents. Its without compromising performance. strengths are small size, unmatched regulation and tran- The LTC1702A’s internal feedback amplifier is a 25MHz sient response and high efficiency. This combination gain-bandwidth op amp, allowing the use of complex makes it ideal for providing multiple low voltage logic multipole/zero compensation networks. This allows the supplies to microprocessors or high density ASICs, in feedback loop to maintain acceptable phase margin at systems using a “2-step” regulation architecture common higher frequencies than traditional switching regulator in portable and advanced desktop computers. 1702afa 7