Analog Devices Step-down Simplified switches are designed for automotive, industrial, and GSM power supplies

Analog Devices LT8645 and LT8646 are 65 V, 8 A synchronous step-down boost/step-down regulators. These regulators feature a Silent Switcher architecture designed to minimize EMI/EMC radiation while achieving high energy efficiency at high switching frequencies. This architecture incorporates bypass capacitors to optimize all of the internal fast current loops and achieve target EMI performance more easily by reducing layout sensitivity. This performance makes the LT8645 and LT8646 ideal for noise-sensitive applications and environments.

Fast, clean, low overshoot switch edges allow the device to operate efficiently at high switching frequencies, thus achieving a smaller overall solution size. With peak current mode control and extremely short 40 ns on-off time, high step-down ratio can be achieved even at high switching frequencies. The LT8646 provides external compensation via a VC pin, enabling current-sharing and fast transient response at high switching frequencies.

Burst Mode operation can achieve ultra-low standby current consumption, pulse frequency hopping mode can achieve full switching frequency under low output load, spread spectrum operation further reduces EMI/EMC radiation. Soft start and trace functions are accessed through TR/SS pins, and thresholds for input voltage UVLO can be set using EN/UV pins.

Other regulators can be synchronized with the LT8645 and LT8646 using CLKOUT pins. These regulators are available in a compact 32-pin LQFN package and operate in a temperature range of -40 °C to +125 °C. The LT8645 and LT8646 are ideal for automotive, industrial, and GSM power supplies.

Features

● Silent Switcher 2 architecture
-   Eliminate PCB layout sensitivity
-   Internal bypass capacitors reduce radiant EMI
-   Optional spread spectrum modulation
-   Achieve ultra-low EMI/EMC radiation on any PCB
● High frequency and high energy efficiency
-   The energy efficiency reaches 95% at 1 MHz, 12 VIN to 5 VOUT
-   The energy efficiency reaches 94% at 2 MHz, 12 VIN to 5 VOUT
● Wide input voltage range: 3.4V to 65V
● Output soft boot and trace
● Small 32 leads 6 mm x 4 mm QFN package
● Run with ultra-low static current Burst Mode®
-   Output ripple < 10 mVP-P
-   2.5μA IQ adjusted 12 VIN to 3.3VOUT
● With low pressure difference under all conditions: 60 mV at 1 A
● External Compensation: Fast Transient Response and current Equalization (LT8646S)
● Run in peak current mode
● Fast minimum on-off time: 40 ns
● Adjustable and synchronous: 200 kHz to 2.2 MHz

Applications

● Automobile power supply
● Industrial power supply
● GSM power supply
● Step-down Step-down/step-down