Datasheet LTC3608 (Analog Devices)

LTC3608 18V, 8A Monolithic Synchronous Step-Down DC/DC Converter Features Description n
8A Output Current
The LTC®3608 is a high efficiency, monolithic synchronous n
Wide VIN Range = 4V to 18V
step-down DC/DC converter that can deliver up to 8A output n
Internal N-Channel MOSFETs
current from a 4V to 18V (20V maximum) input supply. It n
True Current Mode Control
uses a valley current control architecture to deliver very n
Optimized for High Step-Down Ratios
low duty cycle operation at high frequency with excellent n
tON(MIN) ≤ 100nsec
transient response. The operating frequency is selected n
Extremely Fast Transient Response
by an external resistor and is compensated for variations n
Stable with Ceramic COUT
in VIN and VOUT. n
±1% 0.6V Voltage Reference
The LTC3608 can be configured for discontinuous or n Power Good Output Voltage Monitor forced continuous operation at light load. Forced continu- n Adjustable On-Time/Switching Frequency ous operation reduces noise and RF interference while n Adjustable Current Limit discontinuous mode provides high efficiency by reducing n Programmable Soft-Start switching losses at light loads. n Output Overvoltage Protection n Optional Short-Circuit Shutdown Timer Fault protection is provided by internal foldback current n Low Shutdown I limiting, an output overvoltage comparator and an optional Q: 15µA n Available in a 7mm × 8mm 52-Lead QFN Package short-circuit shutdown timer. Soft-start capability for sup- applications ply sequencing is accomplished using an external timing capacitor. The regulator current limit is user programmable. n A power good output voltage monitor indicates when Point of Load Regulation n the output is in regulation. The LTC3608 is available in a Distributed Power Systems compact 7mm × 8mm QFN package. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 6100678, 6580258, 5847554, 6304066. typical application
High Efficiency Step-Down Converter Efficiency and Power Loss vs Load Current
187k 0.1µF VOUT VON ION 100 10000 VIN RUN/SS VIN 95 4V TO 18V EFFICIENCY 10µF 90 100pF LTC3608 ×3 1000 POWER LOSS (mW) 0.8µH V 85 OUT SW 2.5V 80 1500pF 8A 0.22µF 100µF 75 100 ITH BOOST ×2 11.3k 70 POWER LOSS EFFICIENCY (%) SGND INTV 65 CC 30.1k 10 FCB 60 VIN = 12V V V 4.7µF 55 OUT = 2.5V RNG EXTV PGND CC = 5V PGOOD 50 1 0.01 0.1 1 10 EXTVCC VFB LOAD CURRENT (A) 3608 TA01b 3608 TA01a 9.53k 3608fc Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts