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

The LT®8645SA/LT8646SA 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 ontime allows high step-down ratios even at high switching frequencies. The LT8646SA 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 spread spectrum operation can further reduce EMI emissions.

APPLICATIONS

* Automotive and Industrial Supplies

* General Purpose Step-Down

* Silent Switcher®2 Architecture

* Ultralow EMI Emissions on Any PCB

* Eliminates PCB Layout Sensitivity

* Internal Bypass Capacitors Reduce Radiated EMI

* Optional Spread Spectrum Modulation

* High Efficiency at High Frequency

* Up to 94% Efficiency at 400kHz, 24VIN to 5VOUT

* Up to 93% Efficiency at 1MHz, 24VIN to 5VOUT

* Wide Input Voltage Range: 3.4V to 65V

* Wide Output Voltage Range: 0.97V to (VIN - 0.5V)

* Ultralow Quiescent Current Burst Mode Operation

* 2.5μA IQ Regulating 12VIN to 3.3VOUT (LT8645SA)

* Output Ripple < 10mVP-P