Noise in SMD resistors

[Pat Pending]

Can anyone recommend good low noise SMD resistors.

From what I've read, the physically bigger resistors (i.e. 1/8W leaded resistors) have better noise performance.

[free_electron]

how low ? susumu has some really low noise smd resistors. the resistive element is a special alloy.

[ejeffrey]

Physical size doesn't really matter, what matters is the type of resistive element, and different package styles have different options.  Resistor noise is a combination of johnson noise and excess noise.  Johnson noise is the same for every resistor, and only depends on R and T.  Excess noise depends on the applied voltage and the type of resistor material.  Wire-wound, metal film and foil resistors have negligible excess noise. Thin film resistors generally have low excess noise, but it depends on the material.  Thick film and carbon composition resistors are noisy.

[Pat Pending]

Thanks - That's good feedback.

This link explained a lot, especially after reading the comments.

http://www.digikey.com/Web%20Export/Supplier%20Content/Stackpole_738/PDF/Stackpole_ThickFilmXThinFilm.pdf?redirected=1

[free_electron]

Go wathc this: it explains the noise created by the actual current lfow.

http://www.susumu-usa.com/products/tf.htm

[Pat Pending]

Thanks Free e-, that was an informative presentation, especially the slides on current noise through the bulk resistance material.

Looks like thin film will have the performance I'm after.