Intersil Video Drivers Equipped With Charge Pumps That Create Negative Voltage
Intersil Corp. introduced what it describes as groundbreaking new 200MHz single supply video drivers, theISL59833 and ISL59837, each equipped with charge pumps that create negative voltage and remove the need for external negative rails.
The newISL59833 and ISL59837 video drivers deliver true single supply operation of video amplifiers using a single +3.3V power supply. Charge pumps on board each device creates a negative voltage of -1.6V from the +3.3V power supply, eliminating the need for external negative rails and the components required for a negative power supply.
Both new drivers handle video signals with black level at ground and the sync pulse below ground, which is said to enable significant reductions in board space and total component cost. They are well suited for systems that require output swing below ground but lack a negative power supply, such as single supply consumer applications like projectors and video conference equipment.
The video drivers provide 200MHz –3dB bandwidth and 50MHz 0.1dB bandwidth with a fixed gain of 2 output buffer. Both devices have an enable pin to power down the op amps, reducing the current to 60mA. TheISL59837 also has a power down feature for the charge-pump, further reducing the current to less than 1mA. DC-accurate output coupling eliminates the need for large output ac coupling capacitors.
Generating the negative voltage internally allows for dc-accurate coupling of video onto a 75Ω double-terminated line. The buffers have an integrated 6dB of compensation, so there is no need for external gain-setting resistors. An external reference voltage can be applied to the REF pin to shift the analog video level down, which enables designers to adjust dc levels of the signal or remove a DAC offset.
The ISL59833 andISL59837 are available now in 16-ld QSOPs and are priced at $1.79 in 1,000-unit quantities.
