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Thick-Film Surface Mounted Resistors - CR Series

TT Electronics has brought out two more resistor series in the smaller 0603 size, which are meant to complement and improve the range of the very dependable CR and HR series. These smaller chips are suitable for integration into compact circuits which require a small footprint and very reliable functionality.

The thick-film elements of this line of resistors make them more tolerant to power surges and hence more dependable performers. This means they can be used in many fields demanding precise and consistent function such as military, aerospace, communication, medical and industrial applications.

Features

  • CECC approved products
  • Available as shorting links
  • Versions that are completely adapted for high temperatures and overload screen can be ordered when reliability is critical
  • They come in seven sizes from 0.503 to 2.512
  • Their resistance ranges from 1 ohm to 100 M ohms
  • Their tolerances go down to 0.1%
  • The solder terminations have a barrier layer of nickel

Electrical Data

Physical Data

The CR resistors from TT Electronics have an optional screened release capability that increases their level of dependability and reduces the field failure risk. This is ideal when designing circuits that require complete reliability of critical circuits within a small PCB area, as they show very low FIT rates compared to other available products.

Construction

This range has an ambient temperature ranging from -55 to +155 oC. Products are built of thick-film material suitable for resistor purposes, glazed over with an additional organic layer coating glaze for more protection. The resistor material is screen-printed on a 96% alumina substrate.

Terminations

There are single-sided or planar terminations of gold for wire bonding, and wrap around terminations for soldering.

Solderability

There is a nickel barrier layer electroplated on the wrap around terminations along with the solder coating which makes them resistant to leaching and allows good solderability. They can survive being immersed in solder solution at 260 °C for 30 seconds.

Marking

The CR resistor series includes both solder and gold wire bond planar terminations, with all required data about the device being printed on the primary package or reel.

Performance Data

Value Range in ohms

Application Notes

Range of Operating Temperatures

CR resistor chips can operate at up to 155 °C, as shown by the performance data. If soldered joints are used, the operating temperature at the joint should not exceed 110 °C. This condition is met when the stated power levels at 70 °C are applied.

Mounting

Automated handling of the CR chip resistor is facilitated by its rectangular outline and the small dimensional tolerances. Either wire bonding or reflow soldering of wrap around terminations can be used to connect the chip resistor electrically to a printed circuit board or a ceramic substrate.

The F terminations are designed for excellent contact and leach resistance. The robust construction allows the resistor to handle submersion in a solder bath for 30 seconds at 260 °C. Due to this advantage, the resistor and other wire-leaded components may be mounted on either side of a printed circuit board.

Packaging

Chip resistors with wrap around terminations are supplied after taping and reeling them on standard tape of 8 mm dimensions, certified to IEC 286-3.

Planar termination chips come in waffle packs.

Ordering Procedure

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