Power Electronics

NEW products

EMI Filters

THE TDK-LAMBDA R series of electromagnetic interference (EMI) filters is available in single-phase and 3-phase versions. Current ratings for the single-phase units range from 0.5 A up to 300 A, with line voltages up to 250 Vac or 250 Vdc and leakage currents of 1 mA. Low leakage models are available with 10 µA of leakage current at 250 Vac, 60 Hz. The 3-phase filters have current ratings from 6 A up to 1,000 A, with line voltages up to 500 Vac or 500 Vdc. The maximum leakage current is 2.5 mA at 250 Vac, 60 Hz or 5 mA at 500 Vac, 60 Hz. For ease of installation, some models can be ordered with wire leads, lug terminals or captive screw terminals. In addition, a choice of either standard chassis-mount or DIN rail-mount on many filter models rated up to 30 A (with screw terminals) is offered.

Single-phase filters are certified to UL 1283, CSA C22.2 No. 8 and EN60939 (up to 30 A). The 3-phase filters are certified to UL 1283 (up to 150 A) and EN60939 (up to 300 A). The operating temperature range is from -25°C to +85°C.

RoHS-compliant, the R series of EMI filters is priced from $7.50 each in 100-unit quantities.


Overvoltage Protection ICs

MAXIM'S MAX14527/MAX14528 overvoltage protection ICs feature 100 mΩ (typ) RON internal FET and protect low-voltage systems against voltage faults up to +28 V. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components.

In addition, the overvoltage protection threshold can be adjusted with optional external resistors to any voltage between 4 V and 8 V. With the OVLO input set below the external OVLO select voltage, the MAX14527/MAX14528 automatically chooses the internal ±2.5% accurate trip thresholds. The internal overvoltage thresholds (OVLO) are preset to 5.75 V typical (MAX14527) or 6.76 V typical (MAX14528). The MAX14527/MAX14528 also is protected against overcurrent events with an internal thermal shutdown.

Offered in an 8-pin TDFN-EP package, the devices operate over the -40°C to +85°C extended temperature range.
Maxim Integrated Products
Sunnyvale, Calif.


Step-Down Converter

LINEAR TECHNOLOGY'S LTC3546 dual-channel, synchronous buck regulator delivers either dual 2-A outputs or 3 A from one channel and 1A from the other, with up to 96% efficiency. Using a constant frequency, current-mode architecture, the converter operates from an input voltage range of 2.25 V to 5 V, making it suitable for single-cell li-ion/polymer or multicell alkaline/NiCad/NiMH applications. Each output is adjustable from 0.6 V to 5 V and features turn-on supply tracking. Separate RUN and Power Good PINs enable independent control of each channel. Additionally, the product's switching frequency can be set at 2.25 MHz or is programmable from 750 kHz to 4 MHz.

The product's Burst Mode operation minimizes quiescent current to 160 uA (both channels on) in no load conditions. The current threshold at which Burst Mode operation begins can be independently programmed for each channel. The device also can be run in pulse-skipping or forced-continuous modes to minimize output ripple. Synchronizable to an external clock, the LTC3546 features a Power Good indicator, external synchronization capability, overtemperature and short-circuit protection.

The LTC3546EUFD is offered in a 4-mm × 5-mm QFN-28 and priced at $3.75 each in 1,000-piece quantities. An industrial-grade version, the LTC3546IUFD, operates from a -40°C to 125°C operating junction temperature and is priced at $4.41 in 1,000-piece quantities.
Linear Technology
Milpitas, Calif.


Hall-Effect Sensors

THESE HALL-EFFECT switches and latches from Allegro are temperature-stable and stress-resistant sensors suited for operation over extended temperature ranges to 150°C. The A1220 and A1221 devices are most commonly used to detect the speed and direction of ring magnets for motor commutation, while the A1120 is used to detect the end position in wiper systems and multiple discrete positions in shift selectors.

Each model includes on a single silicon chip: a voltage regulator, Hall-voltage generator, small-signal amplifier, chopper stabilization, Schmitt trigger and short-circuit protected open-collector output that can sink up to 25 mA. An on-board regulator permits operation with supply voltages of 3 V to 24 V. These devices also can be used in 3-V applications, and further external resistance can be added in series with the supply pin for greater protection against transient events. Package styles include type LH, a modified SOT23W surface-mount package, and type UA, a 3-lead ultramini SIP for through-hole mounting. Pricing for the devices is $0.41 to $0.49
Allegro MicroSystems
Worcester, Mass.


DC-DC Converter

ENPIRION'S EN5337QI is an ultrasmall 3-A synchronous buck dc-dc converter featuring an integrated inductor. According to the company, the product is a power supply on a chip (PwrSoC) in a 28-mm2 package — less than half the size of Enpirion's previous 3-A solutions, and one-third the size of competitor's offerings.

With a power density of 149 W/in.2 (23 W/cm2), the EN5337QI is suitable for high-volume, mass-market electronics. Key features of the EN5337QI include 3-A continuous output current capability; wide input voltage range of 2.375 V to 5.5 V; 92% peak efficiency; low-voltage ripple and noise; 5-MHz operating frequency; and switching frequency that can be phase locked to an external clock to eliminate or move unwanted beat frequencies out of band. Protection features include overcurrent protection, thermal shutdown and undervoltage lockout circuit

Available now, pricing for the EN5337QI is $2.50 for quantities of 1,000 parts.
Bridgewater, N.J.


Bidirectional OVP

THE NCP370 from ON Semiconductor is the industry's first integrated bidirectional device offering positive and negative (±) overvoltage protection (OVP) for cell phones, MP3/4, PDAs and GPS systems, as well as overcurrent protection (OCP) for portable accessories such as FM transceiver, load speakers and flash modules.

The product improves the front-end protection of portable devices by providing positive protection up to +28 V and negative protection down to -28 V. Using an innovative architecture, this single device also provides OCP for the external accessories — which are connected on the bottom connector — and supplied via an li-ion battery.

Integrated low on-resistance (RON) N-channel MOSFETs effectively support the direct high charge current up to 1.3 A requested by the portable electronics industry's latest lithium battery charge levels. Available with several overvoltage thresholds to address the maximum rating of the downstream applications, the device offers a second “reverse” mode, enabling the regulation of the reverse current coming from a portable device's battery to supply the external accessories such as an FM transceiver, audio functions or flash capabilities universally connected on the bottom connector of the portable devices.

In addition, the NCP370 is designed to internally limit current up to 1.6 A — a value that can be externally decreased by a pull down resistor — thus eliminating the need for an external OCP device in the application, reducing production costs and lessening the required PCB area in the final portable application. The standby current of the device, which is lower than 1 µA, avoids any battery discharge when the wall adapter is unplugged or when the phone is off, increasing battery life and limiting recharge iterations.

The NCP370MUAITXG is available in a 3-mm × 3-mm × 0.55-mm LLGA-12 Pb-free, RoHS-compliant package, and is priced at $0.80 per unit in 3,000-unit quantities.
ON Semiconductor


USB/Charger Detector

FAIRCHILD SEMICONDUCTOR'S FAN3989 incorporates an on-board FET and features built-in automatic detection that allows the device to sense the presence of a USB charger, all in a single package. This integrated automatic detection feature simplifies design by eliminating external circuitry, which, in turn, saves 15% to 20% board space compared to discrete implementations. Its overvoltage protection capability is suitable for addressing emerging safety standards, which is important for cell phones. The FAN3989 also acts as a USB connection monitoring device to determine if a USB device or a battery-charging device is connected. The product sends a signal to the system controller to indicate the presence of a USB charging device. In addition, the product monitors VBUS for over- or undervoltage conditions, setting the FLAG 2 pin low if VBUS is less than 3.3 V or more than 6 V, while turning off the internal PMOS load switch.

Featuring ultracompact 8-lead MLP packaging, the FAN3989 uses Pb-free terminals and is characterized for moisture sensitivity in accordance with the Pb-free reflow requirements of the joint IPC/JEDEC standard J-STD-020. Pricing in 1,000 pieces is $0.46.
Fairchild Semiconductor
San Jose, Calif.


Single-Output Adapters

PHIHONG USA has added 48-V output models to its existing PSAA60W and PSAA60M single-output adapter series. According to the company, the PSAA60W-480 2-wire adapter and the PSAA60M-480 3-wire adapter better address networking, data communications and IP applications. However, adapters in both series are suitable for portable equipment, networking, peripherals and gaming machines.

The PSAA60W and PSAA60M adapters both comply with the U.S. Energy Independence and Security Act of 2007 (EISA). They also comply with Class B conducted and radiated electromagnetic emissions. In addition, the adapters bear cUL/UL, CE and CB safety markings and approvals. Additionally, the 12 -V, 15-V, 18-V and 24-V models in the series feature TUV safety markings and approvals.
Phihong USA
Fremont, Calif.


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