Datasheet LTC3807 (Analog Devices)

LTC3807 Low IQ, Synchronous Step-Down Controller with 24V Output Voltage Capability
FEATURES DESCRIPTION
n
Wide VIN Range: 4V to 38V (40V Abs Max)
The LTC®3807 is a high performance step-down switching n
Low Operating IQ: 50μA
regulator DC/DC controller that drives an all N-channel n
Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
synchronous power MOSFET stage. A constant fre- n
RSENSE or DCR Current Sensing
quency current mode architecture allows a phase-lockable n Phase-Lockable Frequency (75kHz to 750kHz) frequency of up to 750kHz. n Programmable Fixed Frequency (50kHz to 900kHz) The 50μA no-load quiescent current extends operating run n Selectable Continuous, Pulse-Skipping or Low Ripple time in battery-powered systems. OPTI-LOOP® compensa- Burst Mode® Operation at Light Load tion allows the transient response to be optimized over n Selectable Current Limit a wide range of output capacitance and ESR values. The n Very Low Dropout Operation: 99% Duty Cycle LTC3807 features a precision 0.8V reference and power n Adjustable Output Voltage Soft-Start or Tracking good output indicator. A wide 4V to 38V input supply range n Power Good Output Voltage Monitor encompasses a wide range of intermediate bus voltages n Output Overvoltage Protection and battery chemistries. The output voltage of the LTC3807 n Low Shutdown IQ: 14μA can be programmed between 0.8V to 24V. n Internal LDO Powers Gate Drive from VIN or EXTVCC n No Current Foldback During Start-Up The TRACK/SS pin ramps the output voltages during n Small 20-Pin 3mm × 4mm QFN and TSSOP Packages start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin se- lects among Burst Mode operation, pulse-skipping mode,
APPLICATIONS
or continuous conduction mode at light loads. n Automotive Always-On Systems L, LT, LTC, LTM, OPTI-LOOP, Burst Mode, Linear Technology and the Linear logo are registered n Battery Powered Digital Devices trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Patents, including 5481178, 5705919, 6611131, 6498466, 6580258, n Distributed DC Power Systems 7230497.
TYPICAL APPLICATION Efficiency and Power Loss vs High Efficiency 12V/10A Step-Down Converter Output Current
VIN 100 10 12.5V TO 38V VIN = 24V 22µF 90 VOUT = 12V VIN INTVCC 2.2µF 80 EFFICIENCY LTC3807 1 70 POWER LOSS (W) 60.4k TG 60 FREQ 0.1µF 4.7nF BOOST 50 0.1 POWER LOSS 15.4k 10µH 4mΩ ITH V SW OUT 40 47pF 12V EFFICIENCY (%) 150µF 10A 30 BG 0.01 20 0.1µF PGND TRACK/SS 10 SENSE+ 0 0.001 VOUT EXTVCC 100k 0.0001 0.001 0.01 0.1 1 10 SENSE– SGND IOUT (A) 3807 TA01b VFB 100k FIGURE 13 CIRCUIT PGOOD INTV Burst Mode OPERATION CC 6.98k 3807 TA01a 3807fa For more information www.linear.com/LTC3807 1 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 Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Package Description Revision History Related Parts