DC to DC Power Supplies (Converters)
Synchronous DC/DC Controller corrects output voltage errors.
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Press Release Summary:
Operating from 4-30 V input supplies, 2-phase, step-down Model LTC3709 eliminates voltage errors introduced by PCB traces and high load currents. Integrated differential amplifier measures output voltage directly at load and compensates for voltage drop error. Suited for driving N-channel MOSFETs, controller delivers up to 40 A to loads as low as 0.6 V. It can operate from 2-90% duty cycle at 200 kHz to convert input voltages ranging from 4.5-28 V to 2.5 V output.
Original Press Release:
Remote Sensed Fast 40A DC/DC Controller Corrects Output Voltage Errors Caused by PCB Traces
Milpitas, CA - December 20, 2004 - Linear Technology Corporation introduces the LTC3709, a 2-phase step-down synchronous DC/DC controller with fast transient response which eliminates voltage errors introduced by PCB traces and high load currents. An integrated differential amplifier measures the output voltage directly at the load and compensates for voltage drop error. It also rejects common mode signals that are capacitively or inductively coupled into the feedback pin through PC traces. With a 100ns on-time, the LTC3709 responds very quickly to load transients and reduces the size of output capacitors. The IC uses on-chip phase-lock loops to achieve phase separation between the two output channels and locking onto an external clock. The LTC3709 can deliver up to 40A to loads as low as 0.6V with fewest input and output capacitors. The LTC3709 is used in applications such as servers, large memory arrays, industrial single-board computers and control systems.
The LTC3709 is a current mode step-down synchronous controller that drives N-channel MOSFETs. The user has the option of designing with sense resistors to optimize current balancing or without them to improve efficiency and reduce solution cost. For proper startup of a system with multiple DC/DC regulators, a TRACK input pin allows the output voltage of the LTC3709 to track the output of other regulators.
The LTC3709 operates from 4V to 30V input supplies and uses a constant on-time, valley current control architecture to deliver very low duty cycles. For example, the LTC3709 can operate from 2% to 90% duty cycle at 200kHz in to convert input voltages ranging from 4.5V to 28V to low 2.5V output. The IC offers fault protection against output overvoltage and short-circuit conditions. The LTC3709 is housed in two packages of 5mm x 5mm QFN and 36-lead SSOP.
The LTC3709 is rated for operation from -40ºC to 85ºC. 1,000-piece price starts at $4.90.
Summary of Features: LTC3709
High Output Current
Coincident or Ratiometric Tracking
True Remote Sensing Differential Amplifier
Sense Resistor Optional
Synchronizable to an External Clock with PLL
0.6V ±1% Reference
2% to 90% Duty Cycle at 200kHz
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
For more information, contact:
Doug Dickinson, Media Relations Manager
Linear Technology Corporation
1630 McCarthy Boulevard
Milpitas, CA 95035-7417
ddickinson@linear.com
408-432-1900
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
