Electronic Design

GPIO Expander Takes A Bite Out Of Power

The ancient Egyptians, Greeks, and Indians were known for attempting to recreate the “Midas touch,” whereby they would practice alchemy in their ongoing quest to find the perfect catalyst to turn lead to gold. Yet they forgot one important aspect of Midas’ legend. King Midas came to hate wealth and splendor and started worshipping Pan, the Greek god of nature. Thus, you could say that Midas came to love all things green.

Catalyst Semiconductor had Pan in mind when it developed its latest 8-bit general-purpose I/O (GPIO) expander IC for I2C and SMBus-based applications (see the figure). The CAT9534 is pin- and function-compatible with the industry-standard CAT9554. Yet while the chip may have a black case, at one-hundredth the standby power of the previous generation, your customers will be saving green while keeping the planet green.

Let’s look at the planet part first. The device provides a standby mode that sips a mere 1-µA maximum supply current. This translates to 2.3 to 5.5 µW over the device’s 2.3- to 5.5-V operating range. Pan would be proud. As for the green savings, the CAT9534 costs $0.83 each in 10,000-piece quantities. I don’t know how many ancient Greek obols that would equate to, but it’s safe to say not many. So what does $0.83 buy these days besides less than a quarter of a gallon of gas? The I/O pins can operate at 2.5, 3.3, and 5 V and up to 400 kHz. They also can sink up to 25 mA and source up to 10 mA, and they may be individually configured via configuration registers. Furthermore, the CAT9534 includes a polarity inversion register, an interrupt output, and internal power-on reset. It promises to remain glitch-free during power-up. And, it operates in the industrial temperature range (–40°C to 85°C).

Applications include white goods like dishwashers and other major appliances; handheld devices such as cell phones, PDAs, and digital cameras; data communication devices, such as routers, hubs, and servers; and other applications using sensors, power switches, LEDs, pushbuttons, and fans.

The CAT9534 is available in 16-pin small-outline IC (SOIC), thinshrink small-outline (TSSO), and thin quad flat no-lead (TQFN) packages that comply with the European Union’s Restrictions on Hazardous Substances. Samples are available now, with production quantities available soon.

TAGS: Components
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