Datasheet LTC3835 (Analog Devices)

LTC3835 Low IQ Synchronous Step-Down Controller
FEATURES DESCRIPTION
n
Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 10V
The LTC®3835 is a high performance step-down switching n
Low Operating Quiescent Current: 80µA
regulator controller that drives an all N-channel synchro- n
OPTI-LOOP
®
Compensation Minimizes COUT
nous power MOSFET stage. A constant-frequency current n
±1% Output Voltage Accuracy
mode architecture allows a phase-lockable frequency of n
Wide VIN Range: 4V to 36V Operation
up to 650kHz. n
Phase-Lockable Fixed Frequency 140kHz to 650kHz
The 80µA no-load quiescent current extends operating n Dual N-Channel MOSFET Synchronous Drive life in battery powered systems. OPTI-LOOP compensa- n Very Low Dropout Operation: 99% Duty Cycle tion allows the transient response to be optimized over n Adjustable Output Voltage Soft-Start or Tracking a wide range of output capacitance and ESR values. The n Output Current Foldback Limiting LTC3835 features a precision 0.8V reference and a power n Power Good Output Voltage Monitor good output indicator. The 4V to 36V input supply range n Clock Output for PolyPhase® Applications encompasses a wide range of battery chemistries. n Output Overvoltage Protection n Low Shutdown I The TRACK/SS pin ramps the output voltage during start- Q: 10µA n Internal LDO Powers Gate Drive from V up. Current foldback limits MOSFET heat dissipation dur- IN or VOUT n Selectable Continuous, Pulse-Skipping or ing short-circuit conditions. n Burst Mode® Operation at Light Loads
Comparison of LTC3835 and LTC3835-1
n Small 20-Lead TSSOP or 4mm × 5mm QFN Package
CLKOUT/
n AEC-Q100 Qualified for Automotive Applications
PART # PHASMD EXTVCC PGOOD PACKAGES APPLICATIONS
LTC3835 YES YES YES FE20/4 × 5 QFN LTC3835-1 NO NO NO GN16/3 × 5 DFN n Automotive Systems All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 5408150, 5481178, 5705919, 5929620, 6304066, 6498466, n Telecom Systems 6580258, 6611131. n Battery-Operated Digital Devices n Distributed DC Power Systems
TYPICAL APPLICATION High Efficiency Synchronous Step-Down Converter Efficiency and Power Loss vs Load Current
CLKOUT VIN VIN 100 100000 PLLLPF 4V TO EFFICIENCY TG 10µF 36V 90 RUN V 0.01µF IN = 12V; VOUT = 3.3V 10000 PGOOD 0.22µF 80 TRACK/SS BOOST POWER LOSS (mW) 70 3.3µH 0.012Ω V I OUT 1000 TH 330pF SW 3.3V LTC3835 60 5A 33k 100pF 50 100 150µF SGND INTV 40 CC EFFICIENCY (%) POWER LOSS 10 20k PLLIN/MODE EXTV 4.7µF 30 CC V 20 FB BG 1 SENSE– 10 62.5k SENSE+ PGND 0 0.1 0.001 0.01 0.1 1 10 100 1000 10000 LOAD CURRENT (mA) 3835 TA01 3835 TA01b Rev. F Document Feedback For more information www.analog.com 1 Document Outline 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 Typical Application Related Parts