Datasheet LTC7138 (Analog Devices)

LTC7138 High Efficiency, 140V 400mA Step-Down Regulator
FeaTures DescripTion
n
Wide Operating Input Voltage Range: 4V to 140V
The LTC®7138 is a high efficiency step-down DC/DC n
Internal Low Resistance Power MOSFET
regulator with internal power switch that draws only 12μA n
No Compensation Required
typical DC supply current while maintaining a regulated n
Adjustable 100mA to 400mA Maximum Output
output voltage at no load.
Current
The LTC7138 can supply up to 400mA load current and n Low Dropout Operation: 100% Duty Cycle features a programmable peak current limit that provides n Low Quiescent Current: 12µA a simple method for optimizing efficiency and for reduc- n Wide Output Range: 0.8V to VIN ing output ripple and component size. The LTC7138’s n 0.8V ±1% Feedback Voltage Reference combination of Burst Mode® operation, integrated power n Precise RUN Pin Threshold switch, low quiescent current, and programmable peak n Internal or External Soft-Start current limit provides high efficiency over a broad range n Programmable 1.8V, 3.3V, 5V or Adjustable Output of load currents. n Few External Components Required n Programmable Input Overvoltage Lockout With its wide input range of 4V to 140V and programmable n Thermally Enhanced High Voltage MSOP Package overvoltage lockout, the LTC7138 is a robust regulator suited for regulating from a wide variety of power sources. Additionally, the LTC7138 includes a precise run threshold
applicaTions
and soft-start feature to guarantee that the power system n Industrial Control Supplies start-up is well-controlled in any environment. A feedback n Medical Devices comparator output enables multiple LTC7138s to be con- n Distributed Power Systems nected in parallel for higher current applications. n Portable Instruments The LTC7138 is available in a thermally enhanced high n Battery-Operated Devices voltage-capable 16-lead MSE package with four missing pins. n Avionics L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks n Automotive of Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical applicaTion Efficiency and Power Loss vs Load Current
100
5V to 140V Input to 5V Output, 400mA Step-Down Regulator
EFFICIENCY 90 L1 80 220µH POWER LOSS (mW) 70 VIN V V IN SW OUT 5V TO 140V C 5V 60 1000 IN LTC7138 1µF COUT 400mA 50 250V RUN ANODE 22µF SS 40 POWER LOSS 100 V EFFICIENCY (%) PRG1 VFB 30 VPRG2 OVLO GND 20 V 10 IN = 12V 10 V 7138 TA01a IN = 48V VIN = 140V 0 1 0.1 1 10 100 1000 LOAD CURRENT (mA) 7138 TA01b 7138f For more information www.linear.com/LTC7138 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts