Datasheet LT8650S (Analog Devices)

LT8650S Dual Channel 4A, 42V, Synchronous Step-Down Silent Switcher 2 with 6.2µA Quiescent Current
FEATURES DESCRIPTION
n Silent Switcher®2 Architecture: The LT®8650S is a dual step-down regulator that delivers n Ultralow EMI on Any PCB up to 4A of continuous current from both channels and n Eliminates PCB Layout Sensitivity supports loads up to 6A from each channel. The LT8650S n Internal Bypass Capacitors Reduce Radiated EMI features the second generation Silent Switcher architecture n Optional Spread Spectrum Modulation to minimize EMI emissions while delivering high efficiency n 4A DC from Each Channel Simultaneously at high switching frequencies. This includes integration of n Up to 6A on Either Channel bypass capacitors to optimize high frequency current loops n Ultralow Quiescent Current BurstMode® Operation: and make it easy to achieve advertised EMI performance n 6.2μA IQ Regulating 12VIN to 5VOUT1 and 3.3VOUT2 by eliminating layout sensitivity. n Output Ripple <10mVP-P The fast, clean, low-overshoot switching edges enable high n Optional External VC Pin: Fast Transient Response efficiency operation even at high switching frequencies, and Current Sharing (Extra 50µA IQ/Channel) leading to a small overall solution size. Peak current mode n Forced Continuous Mode control with a 40ns minimum on-time allows high step n High Efficiency at High Frequency down ratios at high switching frequencies. n 94.6% Efficiency at 2A, 5VOUT from 12VIN at 2MHz n 93.3% Efficiency at 4A, 5V Burst Mode operation features a 6.2μA quiescent current OUT from 12VIN at 2MHz n Fast Minimum Switch-On Time: 40ns resulting in high efficiency at low output currents, forced n Wide Input Voltage Range: 3.0V to 42V continuous mode allows fixed switching frequency opera- n Adjustable and Synchronizable: 300kHz to 3MHz tion over the entire output load range, and spread spectrum n Small 4mm × 6mm 32-Pin LQFN Package operation can further reduce EMI emissions. External VC pins allow optimal loop compensation for fast transient
APPLICATIONS
response. The VC pins can also be used for current sharing and the CLKOUT pin enables synchronizing two LT8650S n General Purpose Step-Down chips to generate a 4-phase, 16A supply. n Automotive and Industrial Supplies All registered trademarks and trademarks are the property of their respective owners. Protected by U.S patents, including 8823345.
TYPICAL APPLICATION 5V/4A, 3.3V/4A 2MHz Step-Down Converter Efficiency
100 VIN1 VIN1 V VIN2 IN2 5.4V TO 42V 3.7V TO 42V 95 4.7µF EN/UV1 EN/UV2 4.7µF 90 V 1.0µH 1.0µH OUT1 VOUT2 85 5V SW1 SW2 3.3V 4A 47µF 4A 80 1M 4.7pF 47µF ×2 4.7pF 1M ×2 75 FB1 FB2 LT8650S 70 191k VCC VC1 VC2 VCC 316k 65 SS1 SS2 EFFICIENCY (%) 60 10nF 10nF 55 50 BIAS V 45 IN1 = VIN2 = 12V CH1 5V RT VCC GND SYNC fSW = 2MHz CH2 3.3V 40 0 1 2 3 4 5 6 15k 1µF LOAD CURRENT (A) 8650s TA01a 8650s TA01b fSW = 2MHz Rev A Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts