LMV7272 * DSBGA PACKAGE

Hello Eli,

All semiconductors are sensitive to light to an extent - and not just visible light, but infrared and ultraviolet, too.

Most devices are packaged in an opaque epoxy plastic package, that blocks ambient light so this is not an issue.

The LMV7272 DSBGA package is essentially a bare die that has solder balls added. So the active circuitry is exposed to environmental light.

Measures have been taken to minimize the effect of light, such as adding metal to layers to block light to internal layers, but it cannot block all light.

The active circuitry is on the bottom of the die (between the solder balls). The top of the package has a thin epoxy layer for handling and marking, as well as the aforementioned metal layers help block light from above. Light can also enter from the corners of the die.

The light needs to be fairly "bright", much brighter than average room light.

There have been instances where light coming from below, such as from keyboard or indicator lights lights on the other side of the PCB, can cause issues. Normally ground planes in the PCB will block the light from below.

The most common effect is a shift in the offset voltage or bias current when exposed to light. Or if the circuit is fairly high-impedance or high gain, some "hum" from modulated light can be introduced to the circuit.

So if the 7272 in the DSBGA package is to be used near any light emitters, some precautions need to be taken to prevent exposure to the light.

Regards,

Hi Eli,

The only other non-bare die comparator is the TLV3691 in a 1x1mm X2SON, but it is a nanopower comparator and is about 45x slower than the LMV7272.

Otherwise, there are several devices in SC-70-5. Is  that "small" enough?

Regards,