Saturday, May 14, 2011

Micro SD Card Keychain Dissasembly

Figured I'd share a tip for anyone that has one of these keychain card readers :



     Pressing in the two red tabs near the top allows the card reader to easily come apart. I hastily took mine apart by pulling and broke the connecting tabs. It was broken to begin with, so no real loss. The PCB is the thinnest I've ever seen. It's two sided and comparable to a sheet of 100 lb weight paper.

     One side has the bare copper for the USB connection and raised wires to make connection with the SD micro card. The other side has a couple surface mount components (I'd guess they are of the 0402 package size, as they are incredibly small), what looks to be a crystal oscillator (with H120C written on it), and an IC ( GL827 ). There is also a silkscreen layout for another IC that is shaped like a U with 4 pins on either side. It is unpopulated.

     The GL827 chip is designed for this application.

From http://www.genesyslogic.com/en/product_view.php?show=9 :
The GL827L is USB 2.0 SD/MMC/MS Flash Card Reader single chip. It supports USB 2.0 high-speed transmission to Secure DigitalTM (SD), SDHC, Mini SDTM, Micro SDTM , T-Flash , MultiMediaCardTM(MMC), RS MultiMediaCardTM (RS MMC), MMC Micro , HS-MMC, MMC-Mobile , Memory StickTM (MS), Memory Stick DuoTM (MS Duo), High Speed Memory StickTM (HS MS), Memory Stick PROTM (MS PRO), Memory Stick PROTM Duo (MS PRO Duo), Memory Stick PRO-HG (MS PRO-HG), Memory Stick ROM, MS PRO Micro (M2) on one chip. As a single chip solution for USB 2.0 flash card reader, the GL827L complies with Universal Serial Bus specification rev. 2.0, USB Storage Class specification ver.1.0, and each flash card interface specification.

The GL827L integrates a high speed 8051 microprocessor and a high efficiency hardware engine for the best data transfer performance between USB and flash card interfaces. Its’ pin assignment design fits to card sockets to provide easier PCB layout. 
Size comparision between the Micro SD card and PCB

The component side of the PCB. 
I scanned this photo and only the IC is in focus.