The following are recommendations for
the power connections to the DMD or DMD PCB:
- Solid planes are required for DMD_P3P3V(3.3V),
DMD_P1P8V and Ground.
- TI strongly recommends partial power planes are used for
VOFFSET, VRESET, and VBIAS.
- VOFFSET, VBIAS, VRESET, VCC, and VCCI power rails must be
kept within the specified operating range. This includes effects from
ripple and DC error.
- To accommodate power supply transient current requirements,
adequate decoupling capacitance must be placed as near the DMD VOFFSET,
VBIAS, VRESET, VCC, and VCCI pins as possible.
- Do not swap DMDs while the DMD is still powered on (this is
called hot swapping). All DMD power supply rails and signals must be 0 volts
(not driven) before connecting or disconnecting the DMD physical
interface.
- Do not allow power to be applied to the DMD when one or
more signal pins are not being driven.
- Decoupling capacitor locations for the DMD must be as close
as possible to the DMD. The pads of the capacitors must be connected to at
least two or three vias to get a very low impedance to ground as shown in
Figure 10-3.
Furthermore, the capacitor must be in the flow of the power trace as it goes
to the input of the DMD.
- It is extremely important to adhere to the Section 9.1 and
Section 9.2 and do
not allow the DMD power-supply levels to be outside of the recommended
operating conditions specified in the DMD data sheet.
These figures show examples of bypass
decoupling capacitor layout.
Figure 10-2 Poor LayoutFigure 10-3 Good Layout