SIMCom manufactures GSM GPRS connectivity modules and recently I have published teardown of their SimCom A7672S and SIMCom SIM800L Module, this is the third in series.
SIMCom SIM900A is a Dual Band GSM GPRS Module, it is 2G connectivity module.
SIMCOM SIM900A is an ultra compact and reliable wireless module. The SIM900A is a complete Dual-band GSM/GPRS solution in a SMT module which can be embedded in the customer applications allowing you to benefit from small dimensions and cost-effective solutions. Featuring an industry-standard interface, the SIM900A delivers GSM/GPRS 900/1800MHz performance for voice, SMS, Data, and Fax in a small form factor and with low power consumption. Dimension of the module is 24mm x 24mm x 3 mm
Below is a typical breakout board of SIMCom SIM900A. SOIC16 Package IC is a MAX232 IC and J8 is the place holder for SIM Card connector.
It was easy to open the RF Shield as it was not directly soldered on the PCB.
Once you open the RF Shield, you will see three chipsets, the biggest one is ofcourse a GSM GPRS Processor G4851EL1 (ARM926EJ-S core), I am yet to identify which company and it’s basic spec. Looks like a ST Ericsson processor based on the Logo.
Found a G4852 Chipset Block diagram, assuming G4851 will be similar. Found in the web archives (mentioned by Guru on my Tweet)
As per ST Ericsson Web page dated way back 2013
The G4852 is the most affordable Dual-SIM Dual-Standby GSM/GPRS solution with best-in-class audio performance and support for multimedia processing. Features such as BluetoothTM, Stereo FM radio and power management, including USB detection/charging, 20V over-voltage are supported providing a great user experience.
The G4852 delivers lowest total-cost-of-ownership and longest battery life, with no compromise on RF performance, audio quality and security.
The G4852 enables handsets that offer highly desirable features at a very affordable price, making this technology available to millions more consumers in emerging and development markets.
PMIC is inbuilt as we see inductors and capacitors on board, see left side under the RF Shield. The part with CF431 marking is a crystal.
The Flash and RAM are off-processor and are in the form of a combo chip which has Ultra low Power 64Mbit Flash and 8Mbit SRAM from STMicroelectronics M36W0R60S.
The third chipset used on the module is RF7166 which is RFMD’s RF Amplifier and SWITCH for GSM GPRS signals.
That’s all in this teardown.
I hope you found it interesting. See you in my next blog soon.
I am currently working as an embedded systems design consultant helping companies build custom embedded products and develop test automation solutions for their PCBs.
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