Datasheet LTC7802-3.3 (Analog Devices)

LTC7802-3.3 40V Low IQ, 3MHz Dual, 2-Phase Synchronous Step-Down Controller with Spread Spectrum
FEATURES DESCRIPTION
n
Wide Input Voltage Range: 4.5V to 40V
The LTC®7802-3.3 is a high performance dual step-down n
Wide Output Voltage Range: 0.8V to 99% • VIN
synchronous DC/DC switching regulator controller that n
Low Operating IQ: 12μA (14V to 3.3V, Channel 1 On)
drives all N-channel power MOSFET stages. Constant fre- n
Fixed 3.3V Output Voltage on Channel 1
quency current mode architecture al ows a phase-lockable n
Spread Spectrum Operation
switching frequency of up to 3MHz. The LTC7802-3.3 n
RSENSE or DCR Current Sensing
operates from a wide 4.5V to 40V input supply range. n Out-of-Phase Controllers Reduce Required Input Power loss and supply noise are minimized by operating Capacitance and Power Supply Induced Noise the two controller output stages out-of-phase. n Programmable Fixed Frequency (100kHz to 3MHz) The very low no-load quiescent current extends operating n Phase-Lockable Frequency (100kHz to 3MHz) runtime in battery powered systems. OPTI-LOOP com- n Selectable Continuous, Pulse-Skipping, or Low pensation allows the transient response to be optimized Ripple, Burst Mode® Operation at Light Loads over a wide range of output capacitance and ESR values. n Very Low Dropout Operation: 99% Duty Cycle The LTC7802-3.3 features a precision 0.8V reference and n Power Good Output Voltage Monitors power good output indicators. The MODE pin selects n Output Overvoltage Protection among Burst Mode operation, pulse-skipping mode, or n Internal LDO Powers Gate Drive from VIN or EXTVCC continuous inductor current mode at light loads. n Low Shutdown IQ: 1.5μA n Side Wettable 4mm × 5mm QFN-28 Package The LTC7802-3.3 additionally features spread spectrum operation which significantly reduces the peak radiated and conducted noise on both the input and output sup-
APPLICATIONS
plies, making it easier to comply with electromagnetic n Automotive and Transportation interference (EMI) standards. n Industrial All registered trademarks and trademarks are the property of their respective owners. n Military / Avionics
TYPICAL APPLICATION
V INTV IN CC 4.5V TO 40V 4.7µF RUN1 VIN RUN2 INTVCC BOOST1 BOOST2 TG1 TG2 0.9µH 0.1µF 0.1µF 1.8µH SW1 SW2 LTC7802-3.3 BG1 BG2 SENSE1+ SENSE2+ 2mΩ 3mΩ SENSE1– SENSE2– VOUT2 VOUT1 EXTVCC VOUT1 5V/10A 3.3V/12A 357k 330µF ITH1 V 220µF FB2 TRACK/SS1 ITH2 TRACK/SS2 68.1k MODE 0.1µF 0.1µF FREQ PLLIN/SPREAD GND 780233 TA01a Rev. 0 Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts