LT8640S/LT8640SA Series

42V, 6A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Catalog

42V, 6A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

Part	Voltage - Input (Min) [Min]	Current - Output	Mounting Type	Frequency - Switching [Min]	Frequency - Switching [Max]	Synchronous Rectifier	Operating Temperature [Min]	Operating Temperature [Max]	Voltage - Input (Max) [Max]	Output Configuration	Output Type	Number of Outputs	Function	Supplier Device Package	Voltage - Output (Max) [Max]	Voltage - Output (Min/Fixed) [Min]	Package / Case	Topology	Grade	Qualification
Analog Devices LT8640SIV#TRPBF	3 V	6 A	Surface Mount	200 kHz	3 MHz		-40 °C	125 ¯C	42 V	Positive	Adjustable	1	Step-Down	24-LQFN (4x4)	42 V	0.97 V	24-TFQFN Exposed Pad	Buck
Analog Devices LT8640SEV#TRPBF	3 V	6 A	Surface Mount	200 kHz	3 MHz		-40 °C	125 ¯C	42 V	Positive	Adjustable	1	Step-Down	24-LQFN (4x4)	42 V	0.97 V	24-TFQFN Exposed Pad	Buck	Automotive	AEC-Q100

Catalog

42V, 6A 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 96% Efficiency at 1MHz, 12VINto 5VOUTUp to 95% Efficiency at 2MHz, 12VINto 5VOUT

• Up to 96% Efficiency at 1MHz, 12VINto 5VOUT

• Up to 95% Efficiency at 2MHz, 12VINto 5VOUT

• Wide Input Voltage Range: 3.4V to 42V

• Output Voltage Range: 0.97V to 10V(LT8640S/LT8643S); 0.97V to (VIN– 0.5V) (LT8640SA/LT8643SA)

• 6A Maximum Continuous, 7A Peak Output

• Ultralow Quiescent Current Burst Mode®Operation2.5µA IQ Regulating 12VINto 3.3VOUT(LT8640S/LT8640SA)Output Ripple < 10mVP-P

• 2.5µA IQ Regulating 12VINto 3.3VOUT(LT8640S/LT8640SA)

• Output Ripple < 10mVP-P

• External Compensation: Fast Transient Response and Current Sharing (LT8643S)

• Robust High VOUTOperation (LT8640SA/LT8643SA)Safely Tolerates High Reverse Current

• Safely Tolerates High Reverse Current

• Fast Minimum Switch On-Time: 30ns

• Low Dropout Under All Conditions: 100mV at 1A

• Forced Continuous Mode

• Adjustable and Synchronizable: 200kHz to 3MHz

• Output Soft-Start and Tracking

• Small 24-Lead 4mm × 4mm LQFN Package

• AEC-Q100 Qualified for Automotive Applications

Description

The LT®8640S/LT8643S/LT8640SA/LT8643SA 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 reducing layout sensitivity. This performance makes the LT8640S/LT8643S/LT8640SA/LT8643SA ideal for noise-sensitive applications and environments.Peak current mode control with a 30ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8643S/LT8643SA has external compensation to enable current sharing and fast transient response at high switching frequencies.Burst Mode operation enables ultralow standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spreadspectrum operation can further reduce EMI emissions.ApplicationsAutomotive and Industrial Supplies