March 29, 2014

SiTime SiT8008 - MEMS oscillator : weekend die-shot

SiTime SiT8008 is a programmable MEMS oscillator reaching quartz precision but with higher reliability and lower g-sensitivity. Also SiTime is one of companies who received investments from Rosnano - Russian high-tech investment fund.

Photo of MEMS die puzzled us for quite some time. Is it some sort of integrated SAW/STW resonator?

The trick is that to reach maximum Q-factor (up to ~186'000 according to patents) MEMS resonator must operate in vacuum. So they package resonator _inside_ the die in hydrogen atmosphere, then anneal it in vacuum so that hydrogen escapes through silicon. So we see here only a cap with contacts to "buried" MEMS resonator. We were unable to reach the resonator itself without x-ray camera or ion mill.

MEMS die size - 457x454 µm.

Thankfully relevant patents were specified right on the die : US6936491 US7514283 US7075160 US7750758 :)



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March 22, 2014

TI TL431 adjustable shunt regulator : weekend die-shot

TI TL431 is an adjustable shunt regulator often used in linear supplies with external power transistor.
Die size 1011x1013 µm.


March 18, 2014

TI LM393 - dual comparator : weekend die-shot

TI LM393 - dual comparator, one of old workhorses of electronics.
Die size 704x748 µm.


March 16, 2014

Ti TS5A3159 - 1Ω analog switch : weekend die-shot

Ti TS5A3159 is an 1.65-5V 2:1 analog switch with ~1Ω matched channel resistance and "break-before-make" feature.
Die size 1017x631 µm, 1µm technology.


February 17, 2014

FTDI FT232RL: real vs fake

For quite some time when you buy FTDI FT232RL chips from shady suppliers you have a good chance of getting mysteriously buggy chip which only works with drivers 2.08.14 or earlier. We've got a pair of such FTDI FT232RL chips - one genuine and one fake and decided to check if there is an internal difference between them. On the following photo - left one is genuine, right one is fake. One can notice difference in marking - on genuine chip it's laser engraved while on buggy it is printed (although this is not a universal distinguishing factor for other chips).

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January 17, 2014

ST 34C02 - 2048-bit EEPROM : weekend die-shot

STMicroelectronics 34C02 is an 2048-bit EEPROM with hardwire write-protect and I2C interface, typically used as SPD chip in DIMM memory modules.
Die size 1542x1422 µm, 1.2µm half-pitch.


January 12, 2014

Microchip 24LCS52 : weekend die-shot

Microchip 24LCS52 is an 2048-bit EEPROM with I2C interface.
Die size 1880x1880 µm, 2µm half-pitch.



Closer look at charge-pump: