Analog Devices has released the Power by Linear™ LTC3310S monolithic synchronous buck converter. The device’s fixed frequency peak current mode architecture is ideal for high step-down ratio applications that demand fast transient response. The LTC3310S is a very small, low noise, monolithic step-down DC/DC converter capable of providing up to 10A of output current from a 2.25V to 5.5V input supply. The part employs Silent Switcher® 2 architecture with internal hot loop bypass capacitors to achieve both low EMI and high efficiency at switching frequencies as high as 5MHz. For systems with higher power requirements, multi-phasing parallel converters is readily implemented.
The LTC3310S ’ 2.25V to 5.5V input range supports a wide variety of applications, including most intermediate bus voltages and its integrated low on-resistance MOSFETs deliver continuous load currents as high as 10A with minimal thermal derating. Output voltages ranging from 0.5V to VIN are ideally suited to point-of-load applications such as high current/low voltage DSP/FPGA/GPU/ASIC designs. Other key applications include optical networking, telecom/datacom power supplies, industrial, automotive systems, distributed power architectures and general medium to high power density systems.
LTC3310S Application Circuit
- Silent Switcher® 2 Architecture: Ultralow EMI Emissions
- High Efficiency—4.5mΩ NMOS & 16mΩ PMOS
- Wide Bandwidth, Fast Transient Response
- VIN Range: 2.25V to 5.5V
- VOUT Range: 0.5V to VIN
- VOUT Accuracy: ±1%
- Peak Current Mode Control
- 35ns Minimum On-Time
- Programmable Frequency to 5MHz
- Shutdown Current: 1µA
- Precision 400mV Enable Threshold
- Output Soft-Start with Voltage Tracking
- Power Good Output
- Die Temperature Monitor
- Configurable for Paralleling Power Stages
- Thermally Enhanced 18-Lead 3mm × 3mm LQFN Package
The LTC3310S ’ low 35ns minimum on-time enables a high step-down ratio power supply at high frequency whilst 100% duty cycle operation delivers low dropout performance. The operating frequency of the LTC3310S can be synchronized to an external clock. The LTC3310S total reference voltage accuracy is ±1% over the –40°C to 125°C operating junction temperature range and additional features include a power good signal when the output is in regulation, precision enable threshold, output overvoltage protection, thermal shutdown, die temperature monitor, clock synchronization, mode selection and output short-circuit protection.
The LTC3310S is available in a thermally enhanced 18-lead 3mm × 3mm × 0.94mm LQFN package. The E- and I- grades are specified from –40°C to 125°C operating junction temperature range.
The LTC3310S uses Analog Devices Silent Switcher® 2 technology which brings new levels of performance for synchronous step-down DC/DC converters, the technology reduces EMC related issues eliminating the need for EMI shielding and simplifying PCB layout.
Click below for a brief overview of Silent Switcher® 2 technology
The LTC3310S device is support by the DC2629A demonstration circuit which is set up to run in Forced Continuous Mode with a 2MHz switching frequency but can be configured to Pulse Skip Mode and different switching frequencies. RT is connected to VIN which sets the MODE/SYNC pin as an input and allows the LTC3310S to sync from an external clock. Connecting the MODE/SYNC pin to VIN sets the mode to Forced Continuous Mode and connecting the MODE/SYNC pin to GND sets the mode to Pulse Skip Mode.
The Efficiency vs. Load graph showing the efficiency and the power loss of the circuit with a 3.3V input in forced continuous mode operation.
The DC2629A also has an EMI filter to reduce conducted EMI. This EMI filter can be included by applying the input voltage at the VIN EMI terminal. The EMI performance of the board is shown in the EMI TEST RESULTS section of the demo manual. The red lines in the EMI performance graphs illustrate the CISPR25 Class 5 peak limits for the conducted and radiated emission tests.