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Xpander Logic
Simple solution to system expansion

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Electronic devices while moving towards smaller more portable packaging, are featuring greater functions. This translates into a more advanced technology requirement with more computational power and memory in the already size-constrained silicon space of microcontrollers or microprocessors.
To address this issue, ST has introduced the new Xpander Logic family to help overcome the limited number of Input/Output (I/O) ports in the microcontroller and microprocessor based embedded systems. Any existing or additional intensive tasks on the central processing unit (CPU) can be reassigned to the Xpander Logic IC at ultra-low power consumption and in very small packages.

Xpander Logic

General Purpse Input/Output Port Expansion


The functions of a GPIO port expander can be obtained by upgrading the CPU with integrated features or by adding a Complex Programmable Logic Device (CPLD)/Field Programmable gate Array (FPGA). However both solutions come with their respective pros and cons:

Xpander Logic
CPU Upgrade
CPLD Addition
Cost
Low
Medium
High
Solution size
Medium
Small
Large
Power consumption
Low
Medium
Medium
Flexibility
Less Flexible
Highly flexible
Flexible
PCB routing
Good
Potentially problematic
Good

Xpander Logic Advantages


Xpander Logic allows the existing system processor to use a wide range of intelligent functions through a standard and high-speed Inter-Integrated Circuit (I2C) serial peripheral interface. All these features are achieved through a minimum change on the existing microprocessor or microcontroller’s firmware. This results in a very flexible, cost-competitive solution to expand the system’s resources compared to the complex implementation of a larger and more expensive CPU or CPLD in the embedded system. A further benefit of the Xpander Logic family is the high optimization for micro-power operation and the advanced power management support that helps modern portable systems preserve and extend battery life.

Xpander Logic Key Features

Very small packages: QFN16 and µTFBGA36
Ultra low power consumption
Flexible voltage interface
Intelligent features: Keypad controller, PWM controller, Rotator controller, ADC/DAC and automatic dimming
8, 16 and 24 I/Os
Open drain interrupt output pin
I2C standard/fast speed
Reset pin

Xpander Logic Portfolio


Part Number
GPIO
Package
Intelligent features
8
QFN16
Basic
24
µTFBGA36
Yes

Application Areas

QWERTY keypads
Mobile phones, smart phones, IP phones
Multifunction printers
Portable multimedia devices
Industrial automation