Differential output sensing and clock synchronization possible

December 22, 2011 – Linear Technology (Country Manager: Hong Sa-kwak) announced the release of the LTC3613, a high-frequency controlled on-time synchronous step-down DC/DC converter capable of differential output voltage sensing and clock synchronization. This controlled on-time, valley current mode architecture raises the operating frequency during transient events to provide a very fast transient response, enabling the LTC3613 to recover from heavy-load steps in just a few clock cycles. The input range of 4.5V to 24V supports a wide range of applications, including most intermediate bus voltages. The LTC3613 is ideal for PoL applications because its integrated N-channel MOSFET can provide a high continuous load current of 15A at output voltages of 0.6V to 5.5V.
The LTC3613's differential amplifier provides true remote output voltage sensing for both positive and negative terminals, offering high-precision regulation regardless of trace run, bias, and IR losses in interconnects (up to ±500mV). With a minimum on-time of 65ns, it enables power delivery with high step-down ratios even during high-frequency operation. The operating frequency is selectable from 200kHz to 1MHz and can be synchronized with an external clock. For high efficiency, output current can be monitored by detecting the DCR voltage drop at the output inductor or using a sense resistor. Additional features include an onboard bias voltage LDO, soft-start or tracking, overvoltage protection, current-limiting foldback, and external VCC control.
The LTC3613 offers excellent total differential output regulation accuracy and is specified to handle all error sources, including line, load, and differential sensing. The LTC3613's total differential output voltage accuracy is +/-0.25% at 25°C, +/-0.67% from 0ºC to 85ºC, and
It is ±1% over the full operating temperature range of -40°C to 125°C. The LTC3613EWKH is available in a thermally enhanced 7mm x 9mm QFN-56 package. Pricing starts at $9.75 per unit for 1,000 units. An industrial-grade version, the LTC3613IWKH, is also available at approximately $11.21 per unit for 1,000 units. Both versions are available for immediate purchase. For more information, please visit www.linear.com/product/LTC3613 .

Photo Caption: 24VIN, 15A Monolithic Synchronous Buck Converter with Differential Output Sensing

Product Features: LTC3613

• Wide input voltage range (4.5V ~ 24V), wide output voltage range (0.6V ~ 5.5V at up to 15A)
• 0.67% output voltage accuracy
• Controlled On-Time Valley Current Mode Architecture
• Excellent current sharing function
• Frequency programmable from 200kHz to 1MHz and synchronized with an external clock
• RSENSE or inductor DCR current sensing features with precision current limiting function
• Rapid transient response
• 500mV common-mode remote grounding possible with differential output voltage sensing
• tON(MIN) = 65ns; tOFF(MIN) = 105 ns
• Overvoltage protection and current limiting foldback function
• PowerGood output voltage monitoring
• Voltage tracking startup
• External VCC input for internal LDO bypassing
• Micropower Shutdown: IQ = 15μA
• 7mm × 9mm 56-pin QFN package