Thin Film Ultraviolet sensor IC - ML8511 - OKI

OKI introduced the ML8511, an SOI-CMOS based ultraviolet (UV) sensor IC that does not require an optical cut filter and has an analog voltage output (with integrated op-amp).

The ML8511 Ultraviolet sensor chip has a built-in operational amplifier, allowing the analog voltage output proportional to the amount of UV light. The optical cut filter can also be eliminated, enabling production of compact, low cost and high mobility Ultraviolet devices.

The output ML8511 Ultraviolet sensor IC can directly connect to microcontroller’s ADC pin. No need for  photo-electric to current conversion circuit.

Oki:
Conventional Ultraviolet sensors use compound semiconductors such as gallium nitride, making it difficult to mount peripheral circuits on a single chip. In addition, because silicon-based Ultraviolet sensors require an optical wavelength cut filter, problems such as piece-to-piece variation in sensor characteristics and decline in sensitivity can occur.

Key spec of ML8511 Ultraviolet sensor IC:

• Max sensitivity wavelength: 35nm
• Current consumption: Typ. 300μa (when operating), 0.1μa (when standby) @3.0
• Output voltage: 1.0V (in dark) - 2.2 V (10mW/cm2 @365nm)
• Operation Voltage: 2.7 to 3.6V
• Temperature range: 0°C to 70°C

Takaki Yamada, Oki, said:

We are pleased to introduce the ML8511, which is the world's first Ultraviolet sensor IC using thin-film SOI. OKI has been researching thin-film SOI-based Ultraviolet sensor ICs with high accuracy and that are easy to embed into mobile devices…

OKI will enhance its product lineup with digital output circuits that connects to micro controllers and combining ambient light sensor *) into a single chip. OKI will provide this configuration for a wide range of applications, including accessory type devices to measure the amount of Ultraviolet in daylight, check UV exposure, and also for home and mobile appliances…

*) Ambient light sensor
This is a sensor that can change the current output according to the surrounding brightness. It can be connected directly to a A/D converter because it can output the amount of current to voltage.

The ML8511 Ultraviolet sensor chip uses SOI-CMOS technology, enabling easy integration, it is well-suited to usage in mounting analog and digital circuits.

SOI-CMOS Thin-film technology
This is a technology to develop CMOS on insulator. It uses an SOI substrate with an embedded Insulator instead of a conventional silicon substrate. This enables lower voltage operation and decreases the effect of leak current temperature, which is attractive for low voltage, low current and low leakage operation.

The ML8511 Ultraviolet sensor chip is scheduled to be in sampling in June 2007, and it will be shipped in 12pin QFN (4.0 x 3.0 x 0.7mm) package. Sample price is 200 Yen.

Source: Oki’s ML8511 Ultraviolet Sensor IC