2011 Rectifer/Diode Review

Sep 27, 2011 11:13 AM
Sam Davis, Editor-in-Chief

Although they are usually limited to only two leads, rectifiers and diodes play an important role in power electronic systems. In 2011, many types of rectifier/diodes were introduced, from bridge rectifiers to Schottky types in silicon and silicon carbide (SiC). Listed below is a review of devices that were received by Power Electronics Technology this year.

Probably the busiest company in terms of introducing rectifiers/diodes in 2011 was Vishay Intertechnology. Starting in January, the company introduced several types of Trench MOS Barrier Schottky (TMBS^®) rectifiers. For solar bypass applications devices offer eSMP^® surface-mount and axial-leaded package options.

These rectifiers are intended to enable higher current densities in low-voltage, high-frequency inverters, and solar cell junction boxes, where they will be used as bypass diodes for photovoltaic solar cell protection.

The V10P45S and 15 A V15P45S are offered in surface-mount SMPC packages with a typical height of 1.1 mm. Designed for automated placement, the SMPC package meets MSL Level 1.

Axial-leaded rectifiers released include the 15 A VSB1545 and 20 A VSB2045 in the P600 package. The devices can handle solder dip temperatures to 275 °C for 10 seconds per JESD 22-B106, and feature a maximum junction temperature of + 150 °C.

The TMBS rectifiers combine their high forward surge capability with low V_F (forward voltage) down to 0.30 V to minimize power losses. They are compliant to RoHS Directive 2002/95/EC and WEEE 2002/96/EC, and are halogen-free according to the IEC 61249-2-21 definition.

Next, Vishay expanded its TMBS^® rectifiers with release of 20 more 45 V devices in four power package types and featuring a wide range of current ratings from 10 A to 60 A (Fig. 1).

The power package devices released include the dual-chip V (B, F, I) T1045C, V (B, F, I) T2045C, V (B, F, I) T3045C, V (B, F, I) T4045C, and V (B, F, I)T6045C. Each device is offered in the power TO-220AB, ITO-220AB, TO-262AA, and TO-263AB packages.

With extremely low VF down to 0.28 V, typical at 5 A , these TMBS rectifiers reduce power losses and improve efficiency in high-frequency DC/DC converters, switch-mode power supplies (SMPS), freewheeling and OR-ing diodes, and reverse battery protection in desktop PCs, servers, and LCD TVs.

The TO-263AB package offers a MSL moisture sensitivity level of 1, per J-STD-020, LF maximum peak of 245°C. The TO-220AB, ITO-220AB, and TO-262AA packages feature solder bath temperatures of 275 °C maximum, 10s, per JESD 22-B106, and are halogen-free according to the IEC 61249-2-21 definition.

Vishay added more TMBS^® rectifiers with 12 more 45 V devices in three power package options that feature a wide range of current ratings from 10 A to 60 A. With extremely low forward voltage drops down to 0.33 V typical at 10 A, the rectifiers are optimized for use in solar cell junction boxes as bypass diodes for protection.

These devices include the dual-chip V(B,F)T1045CBP, V(B,F)T2045CBP, V(B,F)T3045CBP, and V(B,F)T6045CBP. Each device is offered in the power TO-220AB, ITO-220AB, and TO-263AB packages.

All rectifiers feature a maximum operation junction temperature of 150 °C and ≤ 200 °C maximum junction temperature in DC forward current without reverse bias (t ≤ 1 hour). The devices are compliant to RoHS Directive 2002/95/EC and WEEE 2002/96/EC.

The TO-263AB package offers a moisture sensitivity level (MSL) of 1, per J-STD-020, LF maximum peak of 245 °C. The TO-220AB and ITO-220AB packages feature solder bath temperatures of 275 °C maximum, 10 s, per JESD 22-B106, and are halogen-free according to the IEC 61249-2-21 definition. 

Single-Phase Single In-Line Bridge Rectifiers

Vishay also released two single-phase single in-line bridge rectifiers in the GSIB-5S package with improved VF over previous-generation devices--down to 0.73 V at + 125 °C --and high forward surge current capability.

The LVB1560 offers a current rating of 15 A and low VF down to 0.73 V at 7.5 A, while the LVB2560 features a current rating of 25 A and forward voltage down to 0.76 V at 12.5 A. The devices’ low VF reduces power loss for increased power efficiency and energy savings.

The bridge rectifiers feature maximum peak reverse voltage ratings of 600 V. Offering an oxide planar chip structure, the devices provide high case dielectric strength of 2,500 V_RMS.

The LVB1560 and LVB2560 are the ideal choice for primary side AC/DC full-wave rectification in switch-mode power supplies for high-efficiency desktop PCs, servers, telecommunication systems, home appliances, and white goods applications. 

The rectifiers’ +275 °C, 10-second solder dipping process per JESD 22-B106 enables high reliability in wave soldering or manual soldering. The devices are compliant to RoHS Directive 2002/95/EC and WEEE 2002/96/EC, and are halogen-free according to the IEC 61249-2-21 definition. 

600 V FRED Pt^® Hyperfast and Ultrafast Rectifiers

In 2011 Vishay also launched 34 new 600 V FRED Pt^® Hyperfast and Ultrafast rectifiers in six power packages (Fig. 2). Combining extremely fast and soft recovery time with low forward voltage drop and reverse recovery charge, the new devices reduce switching and conduction losses in high-efficiency SMPS PFC (power factor correction) applications.

Applications include PFC in SMPS applications; input booster circuits; high-frequency output rectification; freewheeling diodes; and adapters. Typical end products will include desktop PCs, servers, telecom equipment, air conditioners, UPS, industrial motor drivers, and solar inverter systems.

Available in the power TO-220AC, TO-220 FULLPAK, TO-263AB (D²PAK), TO-262 (I²PAK), TO-247AC, and modified TO-247AC packages (in addition to bare die/wafers), the rectifiers feature five forward voltage classes from 1.07 V to 3.40 V at 8 A and 15 A, and 2.0 V to 2.65 V for 30 A devices. 

Reverse recovery time at room temperature starts at 17 ns (at IF = 8 A, di/dt = 200 A/µs, VR = 390 V), while reverse recovery charge at + 125 °C starts at 77 nC (at I_F = 8 A, di/dt = 200 A/µs, V_R = 390 V). 

The new rectifiers are part of Vishay’s Hyperfast “H” and “X” series and Ultrafast “L” series. In addition, the new “U” series was specifically developed for ultrafast soft recovery time. The devices feature an improved chip design for increased reliability exceeding standard requirements for resistance to moisture and I_R stability over time.

The rectifiers offer a maximum operating junction temperature of +175 °C for a more robust and cost-effective design, and extremely low leakage. Compliant to RoHS Directive 2002/95/EC (the TO-247AC package is completely lead [Pb]-free), the devices are halogen- free according to the IEC 61249-2-21 definition, and designed and qualified according to JEDEC-JESD47.

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