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Product News I Power Management

Step-Down µModule regulator features adjustable output current limit

Allegro unveils automotive low-side MOSFET pre-driver IC

Linear Technology has introduced the LTM8052, a 36V input constant frequency step-down µModule regulator with an adjustable output current limit up to 5A. The adjustable current limit helps system designers set the maximum power delivered to a load, minimising the output rating of the upstream AC/DC or DC/DC power supply. Additionally, the LTM8052 is capable of sourcing or sinking current while regulating an adjustable output voltage. For simple noise filtering, the LTM8052 operates at a constant frequency throughout the entire output current range. The µModule regulator converts an input voltage between 6V and 36V to an adjustable output voltage between 1.2V to 24V. In a 12V input to 2.5V output application, the LTM8052 achieves a peak operating efficiency of 88% at 2A. Applications include industrial, medical imaging and communications point of load, charge balancing and Peltier thermoelectric module drivers. The LTM8052’s 10% accurate current limit is an improvement over traditional step-down

regulators whose current limit can be 40%-50% greater than the actual output current. With the LTM8052, a lower power and less costly upstream power supply can be installed, which would otherwise require a greater output power rating to prevent a collapse of the voltage rail under an overcurrent or short-circuit condition. The current limit may also be compensated for temperature using a thermistor for improved thermal management. When sinking current, the µModule regulator recovers energy, transferring it to the input rail rather than dissipating it as heat in conventional methods. For noise-sensitive applications, the LTM8052 can be synchronized to an external clock frequency in the range of 100kHz to 1MHz. Additional features include externally adjustable soft start, adjustable switching frequency and thermal shutdown. The LTM8052 is packaged within a thermally

efficient 11.25mm x 15mm x 2.82mm LGA package.

Linear Technology |

Allegro MicroSystems Europe has launched the A3944, a low-side MOSFET pre-driver IC targeted at the automotive market.

The device, which complements Allegro's existing automotive pre-driver family, is a programmable 6-channel low-side MOSFET control IC, with a 50 V rating on drain feedback inputs which makes it suitable for use in automotive diesel applications.

An extensive diagnostics and wide operating voltage range makes the device suitable for the automotive market, but it may also be used in consumer and industrial applications. Each channel of the AQ3944 is controllable by a combination of parallel and serial inputs, and provides sufficient gate drive current to allow PWM control up to 10 kHz, depending on the MOSFET gate charge. Each channel provides independent fault diagnostics for short-to- ground and open-load conditions when in the

"off" state, and short-to-battery when in the "on" state. A short-to-battery condition can disable the output until reset or for a programmable retry time. Each channel provides independently

programmable fault thresholds and blanking times. In addition to channel state control, channel fault masking, fault thresholds and fault timers are programmed through an SPI compatible serial interface. The serial interface also provides read-back of the fault status for each channel. Digital inputs and outputs are compatible with 3.3 V and 5 V supplies. The A3944 is available in a 28-lead TSSOP (LP) package with exposed pad for enhanced thermal dissipation and is lead (Pb) free with 100% matt tin-plated lead-frames.

Allegro Microsystems |

LOW ENERGY FOR HIGH PERFORMANCE Single-cell Battery Bluetooth low energy Controller EM9301

Components - UK Representative for EM.


• Single Cell 1.5V battery operation • Supply voltage range 0.8V to 3.6V • RF mode peak current 12.5mA • Master and Slave compliant with Bluetooth specification 4.0 • Power down mode 800nA • On air data rate 1Mb/s • SPI or UART interface


• Remote sensing • Wireless mice and keyboards • Wireless sensors in watches • Wireless sports equipment • Alarm and security systems

Phone: 01908 521455 Email: Components in Electronics November 2011 27

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