The LTC3255 is a switched-capacitor step-down DC/DC converter that produces a regulated output of 2.4V to 12.5V adjustable from a 4V to 48V input. In applications where the input voltage exceeds twice the output voltage, 2:1 capacitive charge pumping extends output current capability beyond input supply current limits. At no load, Burst Mode® operation cuts VIN quiescent current to 16µA.
With its integrated VIN shunt regulator, the LTC3255 excels in 4mA to 20mA current loop applications. The device enables current multiplication; a 4mA input current can power a 7.4mA load continuously. Alternatively, the LTC3255 serves as a higher efficiency replacement for linear regulators and provides a space-saving inductor-free alternative to buck DC/DC converters.
This fault-protected, step-down charge pump from Linear Technology is a versatile high voltage step-down switched capacitor converter that delivers up to 50mA of output current. In applications where the input voltage exceeds twice the output voltage, a charge pump offers nearly twice the efficiency of an equivalent linear regulator, and provides a space-saving inductor-free alternative to switching DC/DC regulators.
This device produces a regulated output of 2.4V to 12.5V adjustable from a wide 4V to 48V input that is +60V/-52V tolerant. At no load, Burst Mode® operation reduces VIN quiescent current to 16µA and 2:1 capacitive charge pumping extends output current capability to approximately twice the input current.
The LTC3255 is well suited for a variety of applications such as industrial control, factory automation, sensors and supervisory control and data acquisition (SCADA) systems, housekeeping power supplies, plus current-boosting voltage regulators for 4mA to 20mA current loops.
The LTC3255 operates either as a general purpose step-down charge pump with 2:1 or 1:1 conversion ratios or it can operate as a current doubling shunt regulator. In normal mode, the conversion ratio is chosen based on VIN, VOUT, and load conditions, and switching between conversion modes is automatic. In shunt mode, the device is forced into 2:1 mode, enabling the LTC3255 to provide a regulated output voltage from a current source input with nearly two times the input current available at the load. For example, this feature enables a 4mA current loop to power a 7.4mA load continuously with a 3.3V regulated output voltage.
This device withstands reverse-polarity input supplies down to -52V and output short-circuit without damage. Safety features, including an output current limit and over-temperature protection further enhance robustness.
The LTC3255 is available in a low-profile (0.75mm) 3mm x 3mm 10-lead DFN and a 10-lead MSOP package, both with a backside metal pad for enhanced thermal performance.
The operating junction temperature of the E- and I-grade versions is -40°C to +125°C. The H-grade device offers -40°C to +150°C operation and the high reliability MP-grade version is specified from -55°C to +150°C. The 1000-piece pricing for the E-grade device starts at $2.30 each, and devices are available from stock.
For more information, visit www.linear.com/product/LTC3255.
Summary of Features of the LTC3255:
- Input Voltage Range: 4V to 48V
- Adjustable Regulated Output: 2.4V to 12.5V, 50mA Maximum
- 16µA Quiescent Current in Regulation at No Load
- Reverse-Polarity Input Protection to –52V
- Multimode Charge Pump (2:1, 1:1) with Automatic
- Mode Switching Maintains Regulation over Wide VIN Range
- Input Voltage Shunt Mode for Current-Fed Applications
- Power Good Output
- Over-Temperature & Short-Circuit Protection
- Operating Junction Temperature: 150°C Maximum
- Thermally Enhanced 10-Lead MSOP & 10-Lead (3mm × 3mm) DFN Packages
Typical Application
Applications
- Industrial Control, Factory Automation, Sensors, and SCADA Systems
- Housekeeping Power Supplies
- Current-Boosting Voltage Regulators for 4mA to 20mA Current Loops
About Linear Technology
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits, was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major public companies in 2000. 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, µModule products, 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.
Linear Technology (UK) Limited
Tel: +44 (0)1628 477066
E-mail: uksales@linear.com
Web site: www.linear.com
Website for product information: http://www.linear.com/product/LTC3255
