SH7205 Datasheet, PDF (1503/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 26 2D Graphics Engine (2DG)
26.5.2 Notes on Usage
(1) Power Supply Pins
Because the D/A output voltage is a micro-voltage with approximately 1 mV per step, any noise
penetrating from the outside of the LSI must be minimized. For this purpose, a ceramic capacitor
approximately 0.01 to 0.1 µF must be placed between each power supply pin and the VSS as close
to the LSI pins as possible. It is recommended to place at least one 10-µF capacitor between each
power supply and VSSA (figure 26.61).
(2) Power Supply Separation
In order to supply as a noise-free voltage as possible to the analog power supply, the system’s
analog power should be supplied to this DAC’s power supply (figure 26.61). Also, VSSA should
be connected to the system’s analog ground.
(3) CBU Pin
The CBU pin is used to connect the phase compensation capacitor for op amps. A capacitor should
be connected between the CBU pin and VCCA. No other elements or circuits should be connected
to CBU pin.
(4) REXT Pin
The REXT pin serves to connect an external resistance element that determines the module’s
reference current. A resistance element appropriate for the RL should be connected between the
REXT pin and VSSA. Notice that any noise on this pin can significantly affect D/A conversion
results.
When reviewing pin layout or designing the board, exercise care that the REXT pin does not
cross, or run parallel to, DAC output or other digital signals.
Rev. 1.00 Mar. 25, 2008 Page 1471 of 1868
REJ09B0372-0100