Overview: THERMOPILE
Thermopile Sensor OTP-538U
Revision Date: 2009/09/09 OTP-538U Introduction
The OTP-538U is a thermopile sensor in classic TO-46 housing. The sensor is composed of 116 elements of thermocouple in series on a floating micro-membrane having an active diameter of 545 μm and with blacken surface to absorb the incident thermal infrared radiation, which induces a voltage response at output terminals. The sensor chip is fabricated by a unique front-surface bulk micromachining technology, which result in smaller size and faster to response ambient temperature change.
The IR window is a bandpass filter having its 50% cut-on wavelength at 5 μm, and cut-down at 14μm. The sensor responses proportionally to the incident IR radiation and has a constant signal response up to its cut-off frequency, which is limited by the sensor thermal time constant of tens millisecond range.
The OTP-538U thermopile sensor provides nearly Johnson-noise-limited performance, which can be calculated by its ohmic series resistance. A thermistor element, with a lead connected to ground, is also provided inside the TO package for ambient temperature reference.
