Analog Integrated Circuit Device Data

Freescale Semiconductor

9

33790

TYPICAL APPLICATIONS

FUNCTIONAL TERMINAL DESCRIPTION

TYPICAL APPLICATIONS

The 33790 is intended for use in a DSI system. This device

supplies the interface between standard logic levels and the

voltage and current required for the DSI bus. Two

independent DSI busses are supported by this part. The

33790 does not form the timing for the DSI bus. This is done

by logic either embedded in a microcontroller or by the

MC68HC55, which uses SPI commands and forms DSI

protocol for communications over the DSI bus.

The pins from the MC68HC55 are made to line up with the

pins connecting to the 33790. This includes all the DSIxF,

DSIxS, and DSIxR pins.

A capacitor attached to CPCAP serves as a charge

reservoir for the gate drive charge pump. This circuit creates

a voltage that is higher than the source of the N-channel

output transistor. This allows turning on of the transistor

enough to prevent any significant voltage drop across it. The

rest of charge pump electronics are completely self-

contained on the IC.