POWER AND LINEAR IC SOLUTIONS

Temperature Compensation IC Simplifies Calibration and Cuts BoM

The new ISL21400 voltage reference from Intersil gives designers programmable control over its temperature coefficient and DC voltage, allowing them to compensate accurately for temperature drift elsewhere in their systems. The device will be particularly useful for bias compensation in RF amplifiers, laser diodes and LCDs, and for linearisation in sensor systems.



Part of Intersil’s newly formed pinPOINT family of precision analogue products, the device combines a precision 1.20V voltage reference with a temperature sensor whose output voltage varies linearly with temperature. The low temperature coefficient reference is scaled by an internal DAC from 0V to 1.20V. The output from the temperature sensor is summed with the reference voltage to produce a temperature dependent output.

The temperature sensor can be programmed to produce a positive or negative change in output with increasing temperature. Slopes from -2.1mV/°C to +2.1mV/°C are available. The two internal voltages are summed by a Programmable Gain Amplifier (PGA) with gains of 1x, 2x and 4x, to scale the output up to 4.8V and the slope to ±8.4mV/°C.

Both reference voltages are programmable with 8-bit resolution. These and the PGA gain are set via an I²C bus and the values stored in non-volatile registers. This means that settings are not lost on power down, eliminating the need for software initialisation at device power up.

The ISL21400 allows engineers to significantly relax the temperature tolerance requirements of the component parts of their designs, with potentially substantial savings in Bill of Materials. It is also able to replace more expensive digital compensation strategies that rely on high resolution A/D converters.

Offered in a cost effective 8-MSOP package and drawing just 250µA of current over the industrial temperature range, the ISL21400 is suitable for a broad range of applications, primarily in the industrial and communications markets.

Features

• Programmable 1.20V ±2% reference voltage
• Programmable temperature slope up to ±8.4mV/°C
• Programmable gain amplifier with output up to 4.8V
• Non-volatile storage of programming registers
• I²C serial interface
• 200µA typical active supply current
• Operating temperature range -40°C to +85°C
• 8-MSOP package
• Pb-free plus anneal available (RoHS compliant)

Applications

• RF power amplifier bias compensation
• LCD bias compensation
• Laser diode bias compensation
• Sensor bias and linearisation
• Data acquisition systems
• Variable DAC reference
• Amplifier biasing

For further information, including a copy of Intersil's ISL21400 Datasheet, please click here