High Reliability Video Switch ICs for Car Entertainment Systems

ROHM has developed general-purpose video switch ICs for increasingly sophisticated car entertainment systems that demand lower current consumption and lower voltage operation. Two lineups, the 6-input/1-output BH7636 and 3-input/1-output BH7633 series- each comprised of four models featuring clamp or bias input and an optional 6dB amplifier and video driver- were specifically designed to process the complex signal switching required from multiple image sources, such as DVD players, car navigation systems, monitor cameras and gaming devices. The ICs are compatible with both 3V and 5V systems and feature a 0uA standby function for low power consumption as well as 6kV ESD resistance (HBM) and a wide operating temperature range (-40ºC to +85ºC) for greater reliability. The units can be combined to match a variety of set specifications for different inputs. In addition, the input coupling capacitors can be used in common, while high capacitance capacitors (470uF), conventionally required at the output, are no longer needed (with units equipped with a video driver), freeing up valuable board space.

Sample shipments began in May (BH7636x Series: 4.2US$, BH7633x Series: 2.5US$) and mass production is planned for August 2007.

· Major features of the BH7636x and BH7633x Series

1. Input coupling capacitors can be used in common when two or more ICs are used in combination
2. Built-in video driver (BH76360FV and BH76330FVM) eliminates the need for output capacitors.
3. Wide operating voltage range: 2.8V to 5.5V
4. Onboard standby mode with mute function (0μA circuit current during standby)
5. Wide operating temperature range: -40ºC to +85ºC
6. High ESD resistance: 6kV+ (HBM)
7. Offered in two compact package types: SSOP-B16 (6.4mm × 5.0mm × 1.35mm, BH7636x Series), MSOP8 (4.0mm × 2.9mm × 0.9mm, BH7633x Series)

· Series Comparison

· Glossary

• Bias input
  A type of input mode suited for S pin color signals, Pb and Pr signals used by component video pins, and RGB signals utilized by RGB pins. Although composite video signals can also be processed using this method, clamp input provides certain advantages.
• Clamp input
  The most popular format for processing composite video signals. Its name derives from its method of fixing (clamping) the lower side of the synchronized signal contained in the composite video signal to a certain voltage. Only composite video signals can be processed with this type of input. It provides a number of advantages over bias input such as decreasing the size of the input coupling capacitors required and enabling larger IC output amplitude.
• Coupling capacitor
  A capacitor that cancels differences in the DC level (electric potential difference) between devices.
• DC offset voltage
  DC level difference (electric potential difference).
• Video driver (75Ω driver)
  A device that passes video signals through a coaxial cable. A 75Ω impedance is required for transmission without reflection or signal distortion.
• 6dB amplifier
  An amplifier that doubles (to 6dB) the signal amplitude. The amplitude is halved as it passes through the video driver. A 6dB amplifier is needed to restore the signal to its original size.
• ESD resistance
  The amount of electrostatic voltage a device can withstand without failure or damage.

	The High Reliability Video Switch ICs