LT8645S Series

65V, 8A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Catalog

65V, 8A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Part	Topology	Qualification	Voltage - Input (Min) [Min]	Package / Case	Synchronous Rectifier	Supplier Device Package	Voltage - Output (Min/Fixed) [Min]	Voltage - Output (Max) [Max]	Frequency - Switching [Max]	Frequency - Switching [Min]	Mounting Type	Function	Voltage - Input (Max) [Max]	Operating Temperature [Min]	Operating Temperature [Max]	Output Type	Grade	Output Configuration	Number of Outputs	Current - Output
Analog Devices LT8645SIV#WPBF	Buck	AEC-Q100	3 V	32-TFQFN Exposed Pad		32-LQFN (6x4)	0.97 V	65 V	2.2 MHz	200 kHz	Surface Mount	Step-Down	65 V	-40 °C	125 ¯C	Adjustable	Automotive	Positive	1	8 A

Catalog

65V, 8A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Key Features

• Silent Switcher®2 ArchitectureUltralow EMI Emissions on Any PCBEliminates PCB Layout SensitivityInternal Bypass Capacitors Reduce Radiated EMIOptional Spread Spectrum Modulation

• Ultralow EMI Emissions on Any PCB

• Eliminates PCB Layout Sensitivity

• Internal Bypass Capacitors Reduce Radiated EMI

• Optional Spread Spectrum Modulation

• High Efficiency at High FrequencyUp to 95% Efficiency at 1MHz, 12VINto 5VOUTUp to 94% Efficiency at 2MHz, 12VINto 5VOUT

• Up to 95% Efficiency at 1MHz, 12VINto 5VOUT

• Up to 94% Efficiency at 2MHz, 12VINto 5VOUT

• Wide Input Voltage Range: 3.4V to 65V

• Ultralow Quiescent Current Burst Mode Operation2.5μA IQRegulating 12VINto 3.3VOUT(LT8645S)Output Ripple < 10mVP-P

• 2.5μA IQRegulating 12VINto 3.3VOUT(LT8645S)

• Output Ripple < 10mVP-P

• External Compensation: Fast Transient Response and Current Sharing (LT8646S)

• Fast Minimum Switch On-Time: 40ns

• Low Dropout Under All Conditions: 60mV at 1A

• Adjustable and Synchronizable: 200kHz to 2.2MHz

• Peak Current Mode Operation

• Output Soft-Start and Tracking

• Small 32-Lead 6mm × 4mm LQFN Package

• AEC-Q100 Qualified for Automotive Applications

Description

The LT8645S/LT8646S synchronous step-down regulator features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of bypass capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by eliminating layout sensitivity.The fast, clean, low-overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 40ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8646S has external compensation to enable current sharing and fast transient response at high switching frequencies.Burst Mode®operation enables ultralow standby current consumption, pulse-skipping mode allows full switching frequency at lower output loads, or spread spectrum operation can further reduce EMI emissions.ApplicationsAutomotive and Industrial SuppliesGeneral Purpose Step-DownGSM Power Supplies