Butler Technologies Flex Circuits

A flexible circuit is a vast accumulation of conductors bonded to a thin dielectric, or insulating film. Silver or Copper may be used for conductivity.

Silver Flex Circuit

• Single Sided
• Double Sided (Thru-Hole)
• Heat Stabilized Polyester
• Embedded SMD (LEDs)
• Carbon Overcoat
• Printed Resistors

Copper Flex Circuit

• Single and Double Sided
• Polyimide or Polyester
• Tin, Nickel, Gold Plating

Termination Methods

ZIF Connectors
Zero Insertion Force connectors are becoming an increasingly popular method to terminate a flexible circuit. Use of a ZIF connector eliminates the need for a mating connector. The flex end "mates" into the connector usually located on the rigid board and can come equipped with a latching feature.

Thru-hole or surface mount connectors
These are the traditionally used connectors in today's circuit boards.

Crimped contacts and displacement connectors

• Contacts crimp through the dielectric material into the copper conductor
• Contacts are available for 0.100" (2.54mm) or 0.050" (1.27mm)
• Centerline housings are also available to encapsulate the contact

Flex Circuits Comparison Chart

Characteristic	Silver Ink	Copper
Printing vs. Etching	Electric conductors are screen-printed onto the film substrate.	Copper is chemically etched away, leaving conductive traces. More expensive than screen-printing.
Pliability/Weight	Silver traces are lightweight and more flexible than solid copper traces.	Solid copper traces are heavier and more durable than softer printed silver traces.
Conductivity	Resistivity approx 50 mOhms/sq 1mm x 80 mm trace = 4 Ohms 0.5mm x 80mm trace = 8 Ohms	High
Price	Low to Moderate	Expensive to very expensive
Soldering	No	Yes
Pitch	Thin	Possible pitch 0.5mm and 0.3mm for ZIF connector