Alpha SF Series

Alpha SF Series

The SF conformally coated precision resistor network series from Alpha Electronics are fully customisable and offers excellent performance in TCR tracking, resistance ratio matching and stability thanks to Alpha's Bulk Metal® foil resistor technology. The SF precision resistor network series offers 2 resistive elements. Each resistive element can range from 30Ω up to 120kΩ all with tight tolerances down to +0.05% absolute and +0.01% matching (the maximum total resistance for the network is 240kΩ).

  • Fully customisable resistor network with 2 resistor elements and 2 different standard circuit layouts to choose from
  • Each resistor element is available in any resistance between 30Ω and 120kΩ
  • Maximum resistance value for complete resistor network of 240kΩ
  • Through-hole conformally coated package
  • Tight absolute tolerance of ±0.05% with an even tighter matching tolerance of ±0.01% available
  • Tight absolute TCR of ±5 ppm/°C (from -25°C up to +125°C)
  • Tight tracking TCR available of between ±1 ppm/°C and ±3 ppm/°C depending on resistance ratio (Rmax. / Rmin.)
  • Power rating of 0.5W for the complete resistor package (at +70°C)
  • Maximum rated operating temperature +70°C
  • Working temperature from -25°C up to +125°C

The SF conformally coated, through-hole, precision resistor network series exhibits excellent high frequency characteristics thanks to Alpha's Bulk Metal® foil resistor technology, making them suitable for the most demanding precision applications.

These resistors are fully customisable including the circuit layout. There are 2 standard circuit types available to choose from:

  • Circuit layout B - independent resistors in the same package
  • Circuit layout C - divider network
For full details, please see the ultra-precision resistor networks supporting document under the technical library tab.

Pin pitch for the Alpha SF series will be in multiples of 2.54mm.

The below table gives the full specifications for each resistor model available including the Alpha SF series:

Alpha SF Specifications

* TCR tracking is dependent on resistance ratio, please see Table 1
** Symbols parenthesized are for part number composition

Table 1
Specifications
Additional Features
  • Fully customisable resistor network with 2 resistor elements
  • Utilises Alpha's Bulk Metal® foil technology for high precision
  • Conformally coated through-hole resistor network
  • Maximum of 2 resistor elements (circuit layouts B and C) with a total resistance of 240kΩ
  • Pin pitch in multiples of 2.54mm
  • Working temperature range of -25°C to +125°C
  • Maximum rated operating temperature of +70°C
Maximum Power Rating
  • 0.5W for the full resistor package (at +70°C)
Maximum Resistance
  • 120kΩ per resistive element
Minimum Resistance
  • 30Ω per resistive element
TCRAbsolute TCR:
  • ±5 ppm/°C (-25°C to +125°C)
TCR Tracking:
  • ±1 ppm/°C (1 ≤ Rmax. / Rmin. ≤ 10)
  • ±2 ppm/°C (10 < Rmax. / Rmin. ≤ 100)
  • ±3 ppm/°C (100 < Rmax. / Rmin.)
ToleranceAbsolute:
  • ±0.05% (A)
  • ±0.1% (B)
  • ±0.5% (D)
  • ±1.0% (F)
Matching:
  • ±0.01% (T)
  • ±0.02% (Q)
  • ±0.05% (A)
  • ±0.1% (B)
  • ±0.5% (D)
  • ±1.0% (F)

We are pleased to provide you with a range of additional content including videos, product datasheets, case studies, white papers and application notes for your reference. Please see below for the latest content available:

 

 

DOCUMENTATION
PDF DocumentAlpha Electronics SE, SF and SS precision conformally coated resistor network series datasheet
PDF DocumentAlpha Electronics ultra-precision resistor network circuit layouts, number of possible elements per layout and TCR information
PDF DocumentAlpha Electronics manufacturing process, adjustment of resistance value construction, and temperature characteristics of resistance information which covers their resistor range including typical characteristics such as their typical 0.14 ppm/°C TCR
PDF DocumentAlpha Electronics additional services and custom products available to compliment their precision and ultra-precision resistor ranges
PDF DocumentAlpha Electronics ultra-precision resistors databook, covering all parts and models they have to offer

 

 

 

VIDEOS
Resistor Stability Put to the Test (Demo Video)

In this video, host Richard Zuratt from VPG puts the stability of the three major resistor technologies — foil, thin, and thick film — to the test. Each resistor type is subjected to an overload pulse and its change in resistance value is recorded. Due to the homogeneous nature of the VPG Bulk Metal® Foil resistor, it is the only of the three to experience no change from the high power pulse. This demonstrated performance makes foil resistors the technology of choice for critical applications where long-term stability and survivability are paramount.
A head to head comparison of the survival rates of precision thin film nichrome (NiCr) resistors versus VFR Bulk Metal Foil resistors in a high humidity environment.

All resistors that are based on nichrome, which is a category that includes both thin film devices and Bulk Metal Foil resistors, are susceptible to electro-chemical corrosion or etching when placed in a high humidity environment and powered with a very low wattage. But since the nichrome element of a Bulk Metal Foil resistor is hundreds of times thicker than the element in a thin film device with the same value, it will last much longer under these conditions. This video shows the actual etching process and survival times for thin film and foil nichrome resistive elements as they are tested in 100% humidity conditions.
Comparison Testing of Chip Resistor Technologies Under High Vibration

Surface-mount resistors suffer physical stresses when exposed to high vibration or thermally unstable environments. Failure modes commonly occur in welds, solder joints, connectors, and terminations, ultimately resulting in circuit failure. In this demonstration, vibration-table-mounted boards are subjected to ±2° deflection 25 times per second and monitored for any ΔR > 0.1%. All the chip resistors failed in 2 to 12 minutes (8K to 16K cycles). But the Alpha MPP molded Bulk Metal® Z-Foil resistor with flexible terminations experienced over a million cycles with no change in resistance.
VIDEOS
Resistor Stability Put to the Test (Demo Video)

In this video, host Richard Zuratt from VPG puts the stability of the three major resistor technologies — foil, thin, and thick film — to the test. Each resistor type is subjected to an overload pulse and its change in resistance value is recorded. Due to the homogeneous nature of the VPG Bulk Metal® Foil resistor, it is the only of the three to experience no change from the high power pulse. This demonstrated performance makes foil resistors the technology of choice for critical applications where long-term stability and survivability are paramount.
A head to head comparison of the survival rates of precision thin film nichrome (NiCr) resistors versus VFR Bulk Metal Foil resistors in a high humidity environment.

All resistors that are based on nichrome, which is a category that includes both thin film devices and Bulk Metal Foil resistors, are susceptible to electro-chemical corrosion or etching when placed in a high humidity environment and powered with a very low wattage. But since the nichrome element of a Bulk Metal Foil resistor is hundreds of times thicker than the element in a thin film device with the same value, it will last much longer under these conditions. This video shows the actual etching process and survival times for thin film and foil nichrome resistive elements as they are tested in 100% humidity conditions.
Comparison Testing of Chip Resistor Technologies Under High Vibration

Surface-mount resistors suffer physical stresses when exposed to high vibration or thermally unstable environments. Failure modes commonly occur in welds, solder joints, connectors, and terminations, ultimately resulting in circuit failure. In this demonstration, vibration-table-mounted boards are subjected to ±2° deflection 25 times per second and monitored for any ΔR > 0.1%. All the chip resistors failed in 2 to 12 minutes (8K to 16K cycles). But the Alpha MPP molded Bulk Metal® Z-Foil resistor with flexible terminations experienced over a million cycles with no change in resistance.

RoHS Compliance

This product is available fully compliant to the RoHS EU directive 2011/65/EU.

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