Summary of ANALOG DEVICES ANNOUNCES 42V, 15A SYNCHRONOUS STEP-DOWN REGULATOR SILENT SWITCHER 2
Analog Devices released the LT8648S, a 42V, 15A synchronous step-down regulator using Silent Switcher 2 architecture to minimize EMI and reduce PCB layout sensitivity by integrating input and boost bypass capacitors. It delivers high efficiency at high switching frequencies (up to 95.5% at 1 MHz), supports 3V–42V input, 25 ns minimum on-time, external compensation, synchronization, burst mode or forced continuous modes, spread spectrum, soft-start/tracking, and power-good. Housed in a 36-lead LQFN, it targets noise-sensitive designs and offers low ripple, low quiescent current, and AEC-Q100 qualification in progress.
Parts used in the LT8648S Project:
- LT8648S synchronous step-down regulator (36-lead 7 mm × 4 mm LQFN)
- Integrated input bypass capacitors (internal to LT8648S)
- Integrated boost capacitors (internal to LT8648S)
- External compensation components connected to VC pin (resistors, capacitors)
- SS pin components for soft-start and tracking (capacitor/resistor)
- EN/UV pin components to set UVLO threshold (resistor network)
- Optional external components for forced continuous or spread spectrum modes (as required)
- PCB for layout implementing Silent Switcher 2 guidelines
Analog Devices announced the release of a new synchronous step-down regulator, LT8648S, that features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of input and boost 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 LT8648S ideal for noise sensitive applications and environments.
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 25 ns minimum on-time allows high step down ratios even at high switching frequencies. External compensation via the VC pin allows for fast transient response at high switching frequencies. The VC pin also enables current sharing and a CLKOUT pin enables synchronizing other regulators to the LT8648S.
Burst Mode operation enables low 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. Soft-start and tracking functionality is accessed via the SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.
Features
- 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 95.5% Efficiency at 1 MHz, 12 VIN to 5 VOUT
- Up to 93% Efficiency at 2 MHz, 12 VIN to 5 VOUT
- Wide Input Voltage Range: 3 V to 42 V
- 15 A Output Current
- Low Quiescent Current Burst Mode® Operation
- 100 µA IQ Regulating 12 VIN to 5 VOUT
- Output Ripple < 10 mVP-P
- External Compensation: Fast Transient Response and Current Sharing
- Fast Minimum Switch On-Time: 25 ns
- Low Dropout Under All Conditions: 35 mV at 1 A
- Forced Continuous Mode
- Adjustable and Synchronizable: 200 kHz to 2.2 MHz
- Output Soft-Start and Power Good
- Safely Tolerates High Reverse Current
- Small 36-Lead 7 mm × 4 mm LQFN Package
- AEC-Q100 Qualification in Progress
Read more: ANALOG DEVICES ANNOUNCES 42V, 15A SYNCHRONOUS STEP-DOWN REGULATOR SILENT SWITCHER 2
- What is the input voltage range of the LT8648S?
The input voltage range is 3 V to 42 V. - What maximum output current does the LT8648S support?
The LT8648S supports up to 15 A output current. - How does the LT8648S minimize EMI?
It uses Silent Switcher 2 architecture and integrates input and boost bypass capacitors to reduce radiated EMI and layout sensitivity. - What efficiency can be expected at high switching frequencies?
Up to 95.5% efficiency at 1 MHz (12 VIN to 5 VOUT) and up to 93% at 2 MHz (12 VIN to 5 VOUT). - What is the minimum switch on-time?
The minimum on-time is 25 ns. - Can the LT8648S synchronize to other regulators?
Yes, it provides a CLKOUT pin to synchronize other regulators to the LT8648S. - Does the LT8648S support low quiescent current modes?
Yes, it supports Burst Mode operation and offers 100 µA IQ while regulating 12 VIN to 5 VOUT. - How is soft-start and tracking implemented?
Soft-start and tracking are accessed via the SS pin. - Is the LT8648S adjustable and synchronizable over a frequency range?
Yes, it is adjustable and synchronizable from 200 kHz to 2.2 MHz. - What package is the LT8648S available in?
It is available in a small 36-lead 7 mm × 4 mm LQFN package.
